Review of Critical Care Medicine

KELOID AND HTSs

HTSs rise above the skin level but stay within the confines of the original wound and often regress over time. Keloids rise above the skin level as well, but extend beyond the border of the original wound and rarely regress spontaneously .Both HTSs and keloids occur after trauma to the skin, and may be tender, pruritic, and cause a burning sensation. Keloids are 15 times more common in darker-pigmented ethnicities, with individuals of African, Spanish, and Asian ethnicities being especially susceptible. Men and women are equally affected. Genetically, the predilection to keloid formation appears to be autosomal dominant, with incomplete penetration and variable expression

Keloids tend to occur 3 months to years after the initial insult, and even minor injuries can result in large lesions

HTSs usually develop within 4 weeks after trauma. The risk of HTSs increases if epithelialization takes longer than 21 days.

Keloids can result from surgery, burns, skin inflammation, acne, chickenpox, zoster, folliculitis, lacerations, abrasions, tattoos, vaccinations, injections, insect bites, ear piercing, or may arise spontaneously.even minor injuries can result in large lesions.Certain body sites have a higher incidence of keloid formation, including the skin of the earlobe as well as the deltoid, presternal, and upper back regions. They rarely occur on eyelids, genitalia, palms, soles, or across joints. Keloids rarely involute spontaneously, whereas surgical intervention can lead to recurrence, often with a worse result.Keloid scars tend to occur above the clavicles, on the trunk, on the upper extremities, and on the face

HTSs They usually occur across areas of tension and flexor surfaces, which tend to be at right angles to joints or skin creases.. A hypertrophic scar can occur anywhere on the body.

Opposite Views?

Sabiston :-Histologically, both HTSs and keloids demonstrate increased thickness of the epidermis with an absence of rete ridges. There is an abundance of collagen and glycoprotein deposition. Normal skin has distinct collagen bundles, mostly parallel to the epithelial surface, with random connections between bundles by fine fibrillar strands of collagen. In HTSs, the collagen bundles are flatter, more random, and the fibers are in a wavy pattern. In keloids, the collagen bundles are virtually nonexistent, and the fibers are connected haphazardly in loose sheets with a random orientation to the epithelium. The collagen fibers are larger and thicker and myofibroblasts are generally absent.

After secretion into the ECM, specific proteases cleave the propeptides of the procollagen molecules to form collagen monomers. These monomers assemble to form collagen fibrils in the ECM, driven by collagen’s tendency to self-assemble. Covalent cross-linking of the lysine residues provides tensile strength. The extent and type of cross-linking vary from tissue to tissue. In tissues such as tendons, where tensile strength is crucial, collagen cross-linking is extremely high. In mammalian skin, the fibrils are organized in a basket-weave pattern to resist multidirectional tensile stress. In tendons, on the other hand, fibrils are in parallel bundles aligned along the major axis of tension

Schwartz :-Keloids and hypertrophic scars have stretched collagen bundles aligned in the same plane as the epidermis, as opposed to normal scar tissue, where the collagen bundles are randomly arrayed and relaxed. In addition, keloid scars have thicker, more abundant collagen bundles that form acellular nodelike structures in the deep dermal portion of the keloid lesion. The center of keloid lesions also contains a paucity of cells in comparison to hypertrophic scars, which have islands composed of aggregates of fibroblasts, small vessels, and collagen fibers throughout the dermis.

Keloid scars is made up of –
a) Dense collagen b) Loose fibrous tissue
c Granulamatous tissue d) Loose areolar tissue

What is true about keloids – (JIPMER 95)
a)It appears immediately after surgery
b)It appears a few days after surgery
c)It is limited in its distribution (grows beyond the limits of the original wound)
d) it is common in old people

Keloid is best treated by – (UPSC 95)
a)Intrakeloidal injection of triamcinolone
b)Wide excision and grafting
c)Wide excision and suturing
d)Deep X-ray therapy

The following statement about keloid is true- A) They do not extend in normal skin   (extreme overgrowth of scar tissue that grows beyond the limits of the original wound)

b)Local recurrence is common after excision

c) They often undergo malignant change

d) They are more common in whites than in blacks

The best cure rate in keloids is achieved by –
a)Superficial X – ray therapy (UPSC 2001)
b)Intralesional injection of triamcinolone
c)Shaving
d)Excision and radiotherapy

Combination is always better.

Surgery:-Excision alone of keloids is subject to a high recurrence rate, ranging from 45 to 100%. There are fewer recurrences when surgical excision is combined with other modalities such as intralesional corticosteroid injection, topical application of silicone sheets, or the use of radiation or pressure

Radiation:-Poor results with 10 to 100% recurrence when used alone. It is more effective when combined with surgical excision. Given the risks of hyperpigmentation, pruritus, erythema, paresthesias, pain, and possible secondary malignancies, radiation should be reserved for adults with scars resistant to other modalities.

Combination therapies:- Intralesional corticosteroid injections decrease fibroblast proliferation, collagen and glycosaminoglycan synthesis, the inflammatory process, and TGF levels. When used alone, however, there is a variable rate of response and recurrence, therefore steroids are recommended as first-line treatment for keloids and second-line treatment for HTSs if topical therapies have failed. Intralesional injections are more effective on younger scars. They may soften, flatten, and give symptomatic relief to keloids, but they cannot make the lesions disappear nor can they narrow wide HTSs. Success is enhanced when used in combination with surgical excision. Serial injections every 2 to 3 weeks are required.

Sabiston:- Intralesional injection of steroids into a keloid scar can inactivate and shrink the scar; such therapy is not indicated for hypertrophic scars.

Scars that are perpendicular to the underlying muscle fibers tend to be flatter and narrower, with less collagen formation than when they are parallel to the underlying muscle fibers. The position of an elective scar can be chosen in such a way to make a narrower and less obvious scar in the distant future. As muscle fibers contract, the wound edges become reapproximated if they are perpendicular to the underlying muscle. If, however, the scar is parallel to the underlying muscle, contraction of that muscle tends to cause gaping of the wound edges and leads to more tension and scar formation.

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Wounds

Primary closure of incised wounds must be done in –
a) 2 hrs b) 4 hrs
c) 6 hrs d) 12 hrs
e) 16 hrs

(Because of the fear of bacterial invasion, primary wound closure beyond 6 to 8 hours after injury was historically proscribed. However, several scientific studies have since shown that when blood supply to a wound is adequate and bacterial invasion is absent, wounds can be safely closed at any time after proper débridement and irrigation)

The tensile strength of wound reaches that of normal tissue by – (PGI 88)
) 6 weeks
c) 4 months
b) 2 months
d) 6 months

NEVER

In the healing of a clean wound the maximum immediate strength of the wound is reached by –
a) 2 – 3 days b) 4 – 7 days
10 – 12 days d) 13 – 18 days

21 days is ans

The tensile strength of the wound starts and increases after – (MAHE 05)
a)Immediate suture of the wound
b)3 to 4 days
c)7-10 days
d 6 months

see figure

When is the maximum collagen content of wound
tissue – (PGI 81, ROHTAK 87)
a)Between 3rd to 5th day
b)Between 6th to 17th day
C) Between 17th to 21st day d) None of the above

In a sutured surgical wound, the process of epithelialization is completed within – (UPSC 07)
a) 24 hours b) 48 hours
c) 72 hours d) 96 hours

Ref schwartz Epithelialization:- While tissue integrity and strength are being re-established, the external barrier must also be restored. This process is characterized primarily by proliferation and migration of epithelial cells adjacent to the wound The process begins within 1 day of injury and is seen as thickening of the epidermis at the wound edge.Re-epithelialization is complete in less than 48 hours in the case of approximated incised wounds, but may take substantially longer in the case of larger wounds, in which there is a significant epidermal/dermal defect.

Sabiston : – Finally, adequate dressing of the closed wound isolates it from the outside environment. Providing an appropriate dressing for 48 to 72 hours can decrease wound contamination. However, dressings after this period increase the subsequent bacterial count on adjacent skin by altering the microenvironment underneath the dressing.

Following are required for wound healing except – a) Zinc
b) Copper c) Vitamin C d) Calcium

Copper is also a component of ferroprotein, a transport protein involved in the basolateral transfer of iron during absorption from the enterocyte. As such, copper plays a role in iron metabolism, melanin synthesis, energy production, neurotransmitter synthesis, and CNS function; the synthesis and cross-linking of elastin and collagen :- Harrison

Copper Deficiency:- Anemia, growth retardation, defective keratinization and pigmentation of hair, hypothermia, degenerative changes in aortic elastin, osteopenia, mental deterioration.

Patient has lacerated untidy wound of the leg and attended the casualty after 2 ‘hours. His wound (AIIMS 84)should be –
a) Sutured immediately  b) Debrided and sutured immediately  c) debrided and sutured secondarily d) Cleaned and dressed

Wound healing is worst at –
(ALL INDIA 93) a) Sternum b) Anterior neck
c) Eyelid d) Lips

After closing deep tissues and replacing significant tissue deficits, skin edges should be reapproximated for cosmesis and to aid in rapid wound healing. Skin edges may be quickly reapproximated with stainless steel staples or nonabsorbable monofilament sutures. Care must be taken to remove these from the wound before epithelialization of the skin tracts where sutures or staples penetrate the dermal layer. Failure to remove the sutures or staples by 7 to 10 days after repair will result in a cosmetically inferior wound

(Anatomic areas where tension is excessive are avoided if possible. The shoulders, back, and anterior chest are high tension and mobile areas where wide scarring is difficult to avoid. Patients are also questioned as to propensity for development of hypertrophic scars or keloid formation. Ears, anterior chest, and shoulders are areas prone to these problematic scars)

Sabiston :-Wound strength increases rapidly within 1 to 6 weeks and then appears to plateau up to 1 year after the injury .When compared with unwounded skin, tensile strength is only 30% in the scar. An increase in breaking strength occurs after approximately 21 days, mostly as a result of cross-linking.The rate of collagen synthesis declines after 4 weeks and eventually balances the rate of collagen destruction by collagenase (MMP-1). At this point the wound enters a phase of collagen maturation.

Taylor:-The tensile strength of the young scar is only about 10% that of normal skin. Scar strength increases to about 30–50% of normal skin by 4 weeks and to 80% after several months.

Robbins:-We now turn to the questions of how long it takes for a skin wound to achieve its maximal strength, and which substances contribute to this strength. When sutures are removed, usually at the end of the first week, wound strength is approximately 10% of the strength of unwounded skin, but it increases rapidly over the next 4 weeks. This rate of increase then slows at approximately the third month after the original incision and then reaches a plateau at about 70 to 80% of the tensile strength of unwounded skin, which may persist for life.

Schwartz:-Wound strength and mechanical integrity in the fresh wound are determined by both the quantity and quality of the newly deposited collagen. The deposition of matrix at the wound site follows a characteristic pattern: Fibronectin and collagen type III constitute the early matrix scaffolding, glycosaminoglycans and proteoglycans represent the next significant matrix components, and collagen type I is the final matrix. By several weeks postinjury the amount of collagen in the wound reaches a plateau, but the tensile strength continues to increase for several more months.²⁰ Fibril formation and fibril cross-linking result in decreased collagen solubility, increased strength, and increased resistance to enzymatic degradation of the collagen matrix. Scar remodeling continues for many (6 to 12) months postinjury, gradually resulting in a mature, avascular, and acellular scar. The mechanical strength of the scar never achieves that of the uninjured tissue.

Factors That Inhibit Wound Healing

Infection

Ischemia

Circulation

Respiration

Local tension

Diabetes mellitus

Ionizing radiation

Advanced age

Malnutrition

Vitamin deficiencies:- Vitamin C Vitamin A

Mineral deficiencies:-Zinc Iron

Exogenous drugs:-Doxorubicin (Adriamycin) Glucocorticosteroids

suture marks are to be avoided, skin sutures should be removed by -  a) hours b) 1 week
2 weeks d) 3 weeks

Epidermal skin sutures function for fine alignment of skin edges. Interrupted sutures are less constrictive than running sutures. The needle enters and exits the skin at 90 degrees in order to evert the skin edges. These skin sutures are removed as soon as adequate intrinsic bonding strength is sufficient. Skin sutures left in place too long result in an unsightly track pattern. On the other hand, sutures removed prematurely risk wound dehiscence. Nonabsorbable sutures on the face are typically removed after 5 days. Sutures in the hand, foot, or across areas that are acted on by motion are left for 14 days or longer .Alternatively, by employing the running intradermal suturing technique, the time constraints of suture removal may be disregarded, and these sutures may be left in place for a longer time without risking a track pattern scar. Finally, epidermal approximation can be achieved without suture using a medical-grade cyanoacrylate adhesive such as Dermabond. Such adhesives are applied across the coapted skin edges only and contribute no tensile strength. Tape closure strips such as Steri-Strips can be applied at the completion of wound closure to help splint the coapted skin edges.

A patient with grossly contaminated wound presents 12 hours after an accident. His wound should be managed by – (UPSC 96)
a)Thorough cleaning and primary repair
b)Thorough cleaning with debridement of all dead and devitalised tissue without primary closure
c)Primary closure over a drain
d)Covering the defect with split skin graft after cleaning

Management of an open wound seen 12 hrs. after
the injury – (AIIMS 87)
a)Suturing
b)Debridement and suture
c)Secondary suturing
d)Heal by granulation

Delayed wound healing is seen in all except-(AP 96)
a) Malignancy b) Hypertension
c) Diabetes d) Infection

All of the following favour postoperative wound dehiscence except – (Karnat 05)
a)Malignancy
b)Vitamin B complex deficiency
c)Hypoproteinaemia
d)Jaundice

Fibroblast in healing wound derived from –
a) Local mesenchyme b) Epithelium (PGI 98)
c) Endothelial d) Vascular fibrosis

(Sabiston) Fibroplasia:- Fibroblasts are specialized cells that differentiate from resting mesenchymal cells in connective tissue; they do not arrive in the wound cleft by diapedesis from circulating cells. After injury, the normally quiescent and sparse fibroblasts are chemoattracted to the inflammatory site, where they divide and produce the components of the ECM.The primary function of fibroblasts is to synthesize collagen, which they begin to produce during the cellular phase of inflammation. The time required for undifferentiated mesenchymal cells to differentiate into highly specialized fibroblasts accounts for the delay between injury and the appearance of collagen in a healing wound. This period, generally 3 to 5 days, depending on the type of tissue injured, is called the lag phase of wound healing.The rate of collagen synthesis declines after 4 weeks and eventually balances the rate of collagen destruction by collagenase (MMP-1). At this point the wound enters a phase of collagen maturation. The maturation phase continues for months or even years. Glycoprotein and mucopolysaccharide levels decrease during the maturation phase, and new capillaries regress and disappear. These changes alter the appearance of the wound and increase its strength.

Degloving injury is – (KERALA 2K)
a) Surgeon made wound b) Lacerated wound
c) Blunt injury d) Avulsion injury
e)Abrasive wound

Avulsion injuries are open injuries where there has been a severe degree of tissue damage. Such injuries occur when hands or limbs are trapped in moving machinery, such as in rollers, producing a degloving injury. Degloving is caused by shearing forces that separate tissue planes, rupturing their vascular interconnections and causing tissue ischaemia. This most frequently occurs between the subcutaneous fat and deep fascia. Degloving injuries can be open or closed. Degloving can be localised or circumferential. It can occur only in the single, subcutaneous plane, but where present in multiple planes, such as between muscles and fascia and between muscles and bone, is an indication of a severe high-energy injury with a limited potential for primary healing. Similar injuries occur as a result of runover road traffic accident injuries where friction from rubber tyres will avulse skin and subcutaneous tissue from the underlying deep fascia (Fig. 3.11). The history should raise the examiner’s suspicion and it is often possible to pinch the skin and lift it upwards revealing its detachment from the normal anchorage. The danger of degloving or avulsion injuries is that there is devascularisation of tissue and skin necrosis may become slowly apparent in the following few days. Even tissue that initially demonstrates venous bleeding may subsequently undergo necrosis if the circulation is insufficient. Treatment of such injuries is to identify the area of devitalised skin and to remove the skin, defat it and reapply it as a full-thickness skin graft. Avulsion injuries of hands or feet may require immediate flap cover using a one-stage microvascular tissue transfer of skin and/or muscle.

In treatment of hand injuries, the greatest priority is – (A1 96)
a)Repair of tendons
b)Restoration of skin cover
c)Repair of nerves
d) Repair of blood vessels

During the surgical procedure – (AIIMS 83)
a)Tendons should be repaired before nerves
b)Nerves should be repaired before tendons
c)Tendons should not be repaired at the same time
d)None is true

In hand injuries first to be repaired is – (A195)
a) Bone b) Tendon
c) Muscle d) Nerve

In the case of injuries, treatment is directed at the specific structures damaged: skeletal, tendon, nerve, vessel, and integument. In emergency situations, the goals of treatment are to maintain or restore distal circulation, obtain a healed wound, preserve motion, and retain distal sensation. Stable skeletal architecture is established in the primary phase of care because skeletal stability is essential for effective motion and function of the extremity. This also results in reestablishing skeletal length, straightening deformities, and correction of compression or kinking of nerves and vessels. Arteries are also repaired in the acute phase of treatment to maintain distal tissue viability. Additionally, extrinsic compression on arteries must be released emergently such as in compartment pressure problems. In clean-cut injuries, tendons can be repaired primarily. In situations in which there is a chance that tendon adhesions may form, such as when there are associated fractures, it is nonetheless better to repair tendons primarily with preservation of their length and if necessary at a later date to perform tenolysis. However, when there are open and contaminated wounds or a severe crushing injury, it is best to delay repair of both tendon and nerve injuries

Prevention of wound infection done by –
a)Pre-op shaving (PGI  05)
b)Pre-op antibiotic therapy
c)Monofilament sutures
d)Wound apposition

SSIs are the most common nosocomial infection in our population and constitute 38% of all infections in surgical patients. By definition, they can occur anytime from 0 to 30 days after the operation or up to 1 year after a procedure that has involved the implantation of a foreign material (mesh, vascular graft, prosthetic joint, and so on). Incisional infections are the most common; they account for 60% to 80% of all SSIs and have a better prognosis than organ/space-related SSIs do, with the latter accounting for 93% of SSI-related mortalities.

Preoperative shaving has been shown to increase the incidence of SSI after clean procedures as well. This practice increases the infection rate about 100% as compared with removing the hair by clippers at the time of the procedure or not removing it at all, probably secondary to bacterial growth in microscopic cuts. Therefore, the patient is not shaved before an operation. Extensive removal of hair is not needed, and any hair removal that is done is performed by electric clippers with disposable heads at the time of the procedure and in a manner that does not traumatize the skin

1.Basic principles include size of the OR, air management (filtered flow, positive pressure toward the outside, and air cycles per hour), equipment handling (disinfection and cleansing), and traffic rules. All OR personnel wear clean scrubs, caps, and masks, and traffic in and out of the OR is minimized.

2.The CDC recommends the use of chlorhexidine showers, and it is reasonable to implement such a policy, particularly in patients who have been in the hospital for a few days and in those in whom an SSI will cause significant morbidity (cardiac, vascular, and prosthetic procedures). Skin preparation of the surgical site is done with a germicidal antiseptic such as tincture of iodine, povidone-iodine, or chlorhexidine. An alternative preparation is the use of antimicrobial incise drapes applied to the entire operative area. Traditionally, the surgical team has scrubbed their hands and forearms for at least 5 minutes the first time in the day and for 3 minutes every consecutive time.

3.As many as 90% of an operative team puncture their gloves during a prolonged operation. The risk increases with time, as does the risk for contamination of the surgical site if the glove is not changed at the moment of puncture. The use of double gloving is becoming a popular practice to avoid contamination of the wound, as well as exposure to blood by the surgical team. Double gloving is recommended for all surgical procedures.Instruments that will be in contact with the surgical site are sterilized in standard fashion, and protocols for flash sterilization or emergency sterilization, or both, must be well established to ensure the sterility of instruments and implants.

Local Wound Related:-Intraoperative measures include appropriate handling of tissue and assurance of satisfactory final vascular supply, but with adequate control of bleeding to prevent hematomas/seromas. Complete débridement of necrotic tissue plus removal of unnecessary foreign bodies is recommended, as well as avoiding the placement of foreign bodies in clean-contaminated, contaminated, or dirty cases. Monofilament sutures have proved in experimental studies to be associated with a lower rate of SSI. Sutures are foreign bodies that are used only when required. Suture closure of dead space has not been shown to prevent SSI. Large potential dead spaces can be treated with the use of closed-suction systems for short periods, but these systems provide a route for bacteria to reach the wounds and may cause SSI. Open drainage systems (e.g., Penrose) increase rather than decrease infections in surgical wounds and are avoided unless used to drain wounds that are already infected.

In heavily contaminated wounds or wounds in which all the foreign bodies or devitalized tissue cannot be satisfactorily removed, delayed primary closure minimizes the development of serious infection in most instances. With this technique, the subcutaneous tissue and skin are left open and dressed loosely with gauze after fascial closure. The number of phagocytic cells at the wound edges progressively increases to a peak about 5 days after the injury. Capillary budding is intense at this time, and closure can usually be accomplished successfully even with heavy bacterial contamination because phagocytic cells can be delivered to the site in large numbers. Experiments have shown that the number of organisms required to initiate an infection in a surgical incision progressively increases as the interval of healing increases, up to the fifth postoperative day.

Finally, adequate dressing of the closed wound isolates it from the outside environment. Providing an appropriate dressing for 48 to 72 hours can decrease wound contamination. However, dressings after this period increase the subsequent bacterial count on adjacent skin by altering the microenvironment underneath the dressing.

Elective cholecystectomy is – (APPG 06)
a) Clean contaminated b) Clean
Dirty d) Contaminated

Which one of the following surgical procedures is considered to have a clean-contaminated wound ?

a),Elective open cholecystectomy for cholelithiasis
b)Hemiorrhaphy with mesh repair
c)Lumpectomy with axillary node dissection
d)Appendectomy with walled off abscess

The accepted range of infection rates has been 1% to 5% for clean, 3% to 11% for clean-contaminated, 10% to 17% for contaminated, and greater than 27% for dirty wounds.

Staphylococcus aureus remains the most common pathogen in SSIs, followed by coagulase-negative staphylococci, enterococci, and Escherichia coli. However, for clean-contaminated and contaminated procedures, E. coli and other Enterobacteriaceae are the most common cause of SSI.

The Vitamin which has inhibitory effect on wound healing is – (MAHE 05)
a) Vitamin-A b) Vitamin-E
c) Vitamin-C d) Vitamin B-complex

Golden period for treatment of open wounds is
….hours – (AIIMS 86, 88)
a) 4 b) 6
c) 12 d) 24

In the first 4 hours after a breach in an epithelial surface and underlying connective tissues made during surgery or trauma, there is a delay before host defences can become mobilised through acute inflammatory, humoral and cellular processes. This period is called the ‘decisive period’ and it is during these first 4 hours after incision that bacterial colonisation and established infection can begin. It is logical that prophylactic antibiotics will be most effective during this time.

Abbey-Estlander flap is used in the reconstruction
of- (AI 05)
a) Buccal mucosa b) Lip
c) Tongue d) Palate

In defects of less than one third the horizontal length, enough redundancy is present to allow primary closure. More complex decisions must be made for defects that are between one third and two thirds of the total lip length. The two categories of lip flap technique are transoral cross-lip flaps and circumoral advancements flaps. Cross-lip flaps include the Abbé flap and the Estlander flap. The Abbé flap was originally designed to reconstruct central upper lip (tubercle) defects with lower lip full-thickness tissue vascularized by one of the labial arteries.The technique requires a second-stage procedure for division of the pedicle. The Estlander flap is similar in principle but is based laterally at the oral commissure and is used to reconstruct lateral upper or lower lip lesions. Both the Estlander and Abbé flaps are denervated, but sensation and perhaps even motor function return over months.The Karapandzic technique is an advancement-rotation flap technique designed for central lower lip defects. Although good function, sensation, and mobility are preserved, a side effect is reduction in the size of the oral aperture. The Webster-Bernard technique uses cheek tissue advancement flaps to replace defects with full-thickness or partial-thickness cheek incisions extended laterally from the commissure (Fig. 45-34). When performed bilaterally, both the Karapandzic and the Webster-Bernard methods can be used to reconstruct a complete upper or lower lip.

Abbé flap upper lip reconstruction. A. Defect and flap design.                     B. Rotation of the flap and primary closure of the donor site.                                     C. Division of the pedicle (after 2 to 3 weeks) and final insetting.

Cock’s peculiar tumour is-(UPSC 86,NIMHANS 87,
a)Papilloma Kerala 87, TN 90 )
b)Infected sebaceous cyst
c)Cylindroma
d)Sqaumous cell carcinoma (RESEMBLES SCC but it’s not SCC)

Epidermoid cyst(syn. sebaceous cyst, wen)
These cysts contain keratin and its breakdown products, surrounded by a wall of stratified squamous keratinising epithelium (the commonly used term sebaceous cyst is incorrect — these cysts only rarely have associated sebaceous glands and do not contain sebum). Epidermoid cysts often have a punctum. They are inherited in an autosomal dominant fashion. The common sites are the face, neck, shoulders and chest, areas favoured by acne vulgaris. Lesions may be solitary but are commonly multiple. They enlarge slowly and may become inflamed and tender from time to time. Suppuration may occur. The contents of an infected cyst become semiliquid and usually very foetid. Recurrent infective episodes cause the cyst wall to become adherent to surrounding subcutaneous tissue, and consequently more difficult to remove. If ulceration occurs it can resemble squamous cell carcinoma to which the term ‘Cock’s peculiar tumour’ may be applied .The contents of a cyst sometimes escape slowly from the duct orifice and dry in successive layers on the skin, forming a ‘sebaceous horn’.Treatment is by surgical excision (except if inflamed, when it is better incised and drained). This can be performed under local anaesthesia; an ellipse of skin including the punctum is removed with the cyst. Unless the wall is completely removed, recurrence is likely.

Cause of persistance of a sinus or fistulae includes-
a)Foreign body (JIPMER 86)
b)Non dependentt drainage
c)Unrelieved Obstruction
d)Presence of malignancy
e)All of the above

Sinuses and fistulas
A sinus is a blind track (usually lined with granulation tissue) leading from an epithelial surface into the surrounding tissues. Pathological sinuses must be distinguished from normal anatomical sinuses (e.g. the frontal and nasal sinuses). A fistula  is an abnormal communication between the lumen or surface of one organ and the lumen or surface of another, or between vessels. Most fistulas connect epithelial­lined surfaces .Sinuses and fistulas may be congenital or acquired. Forms which have a congenital origin include preauricular sinuses, branchial fistulas , tracheo-oesophageal fistulas  and arteriovenous fistulas.The acquired forms often follow inadequate drainage of an abscess. Thus, a perianal abscess may burst on the surface and lead to a sinus (erroneously termed a blind external ‘fistula’). In other cases, the abscess opens both into the anal canal and on to the surface of the perineal stem resulting in a true fistula-in-ano .Acquired arteriovenous fistulas are caused by trauma or operation (for renal dialysis).
  Persistence of a sinus or fistula
  The reason for this will be found among the following:
•  a foreign body or necrotic tissue is present, e.g. a suture, hairs, a sequestrum, a faecolith or even a worm (see below);
•  inefficient or nondependent drainage: long, narrow, tortuous track predisposes to inefficient drainage;
•  unrelieved obstruction of the lumen of a viscus or tube distal to the fistula;
•  high pressure, such as occurs in fistula-in-ano due to the normal contractions of the sphincter which force faecal material through the fistula;
•  the walls have become lined with epithelium or endothelium (arteriovenous fistula);
•  dense fibrosis prevents contraction and healing;
•  type of infection, e.g. tuberculosis or actinomycosis;
•  the presence of malignant disease
•  ischaemia;
•  drugs, e.g. steroids, cytotoxics;
•  malnutrition;
•  interference, e.g. artefacta;
•  irradiation, e.g. rectovaginal fistula after treatment for a carcinoma of the cervix;
•  Crohn’s disease;
• high-output fistula, e.g. duodenocutaneous fistula.

Premalignant conditions of the skin include –
a)Bowen disease (JIPMER 86)
b)Pagel’s disease of nipple
c)Leukoplakia
d)Solar keratosis
e)All of the above

Premalignant lesions :-Actinic keratoses
Bowen’s disease
Erythroplasia of Querat
Radiodermatitis
Chronic scars(A carcinoma which develops in a scar (Marjolin’s ulcer) )
Sebaceous epidermal naevus
Porokeratosis

Melanoma should be excised with a margin of –
a) 2 cm b) 5 cm (UPSC 88)
c) 7 cm d) 10 cm

Harrison also recommends same treatment for Melanoma as described in above figure.

Hidradenitis suppurativa. is found to occur in – (JIPMER 86, AIMS 87)
a) Axilla b) Circumanal
c) Scalp d) Groin

Hidradenitis suppurativa. :- This is a chronic infection of apocrine glands around the anal margin giving rise to numerous sinuses. The mons pubis and groin can also be affected. After excision of the area, granulation and healing ate accelerated by using Silastic foam dressing (Hughes).

The term universal tumour refers to – (PGI 88)
a) Adenoma b) Papilloma
c) Fibroma d) Lipoma

Lipoma
A lipoma is a slowly growing tumour composed of fat cells adult type. Lipomas may be encapsulated or diffuse. It occur anywhere in the body where fat is found and earn tl titles of the ‘universal tumour’ or the ‘ubiquitous tumour The head and neck area, abdominal wall and thighs are particularly favoured sites.

Hydrocele is a type of ….cyst – (PGI 88)
a) Retention b) Distension
c) Exudation d) Traumatic

Acquired cysts
Retention cysts are due to the accumulated secretion of a gland behind an obstruction of a duct. Examples are seen in the pancreas, the parotid, the breast, the epididymis and Bartholin’s gland. A sebaceous cyst starts with the obstruction of a sebaceous gland, but this is followed by the down-growth and the accumulation of desquamated epidermal cells, thus turning it into an epidermoid cyst. In the epididymis, if the retention cyst contains sperms, it is known as a ‘spermatocele’.

Distension cysts occur in the thyroid from dilatation of the acini, or in the ovary from a follicle. Lymphatic cysts and cystic hygromas are distension cysts.

Exudation cysts occur when fluid exudes into an anatomical space already lined by endothelium, e.g. hydrocele, a bursa, or when a collection of exudate becomes encrusted.

Cystic tumours. Examples are cystic teratomas (dermoid cyst of the ovary) and cystadenomas (pseudomucinous and serous cystadenoma of the ovary).
Ganglia. Implantation dermoids arise from squamous epithelium which has been driven beneath the skin by a penetrating wound. They are classically found in the fingers of women who sew assiduously and metal workers.

Sebaceous cyst does not occur in the …. – (PGI 88)
a) Scalp b) Scrotum
c) Back d) Sole

Sebaceous cysts are common in the scrotal skin. They are usually small and multiple.

Fordyce spots are – (All India 95)
a)Ectopic sebaceous glands
b)Ectopic eccrine
c)Ectopic apocrine
d)Ectopic mucossal glands

Broke’s tumor is a tumor of–
a)Superficial dermal vesels
b)Sweat glands
c)Hair follicles
d)Sebaceous glands

Commonest site for rodent ulcer is – (PGI 88)
a) Inner canthus b) Outer canthus
c) Angle of mouth d) Cheek

Squamous cell carcinoma can arise from-(PGi88)
a)Long standing venous ulcers
b)chronic lupus vulgaris
c)Rodent ulcer
d)All of the above

There is a strong correlation with damage to the skin by the sun , and can be experimentally produced by ultraviolet light. Occa­sionally it arises as a complication of long-standing chronic granulomas, such as syphilis, lupus vulgaris and leprosy, chronic ulcers, osteomyelitis, Hydradenitis suppurativa, long-standing venous ulcers or old burn scars

The best results in treatment of capillary nevus have been achieved by – (AIIMS 84)
a)Full thickness skin graft
b)Dermabrasion
c)Tatooing
d)Argon laser treatment

Capillary malformation, usually referred to as a port-wine stain or nevus flammeus, is the most common type of vascular malformation

Vascular malformations:-These are structural and morphological anomalies due to faulty embryological morphogenesis. The lesions are present at birth, grow commensurate with the child and do nor regress. They can lead to underlying soft tissue or bony hypertrophy, nodular development and discoloration as a consequence of blood vessel ectasia with age. The natural history of these lesions is determined by their haemodynamic and Iymphodynamic characteristics.
• High-flow lesions include arterial malformations and arteriovenous malformations (arterial plexiform angiomas, cirsoid aneurysm).
• Low-flow lesions include lymphatic (LM) venous (VM) and capillary (CM — port-wine stain). Frequently these lesions combine arterial, venous and lymphatic elements.
Port-wine stains:-Port-wine stains are intradermal capillary mal­formations that change very little throughout life, although the colour may alter a little and they may become nodular in some areas. Treatment is for reason of appearance. Treatment of choice for these lesions is the use of the pulsed tunable dye laser.

Eleven month old child presents with erythematous lesion with central clearing which has been decreasing in size – (Al 97)
a)Strawberry angioma
b)Nevus
c)Portwine stain
d)Cavernous haemangioma

Malignant melanoma most often develops from –
a)Hairy naevus (SGPGI 05)
b)Junctional naevus
c)Intradermal naevus
d)Blue naevus

The aim of differential diagnosis is to distinguish benign pigmented lesions from melanoma and its precursor. If melanoma is a consideration, then biopsy is appropriate. Some benign look-alikes may be removed in the process of trying to detect authentic melanoma. Table 83-5 summarizes the distinguishing features of benign lesions that may be confused with melanoma.

Full thickness skin graft can be taken from the following sites except – (AIIMS 87)
a) Elbow b) Back to neck
c) Supraclavicular area d) Upper eyelids