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CHAPTER 16
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The Skin and Subcutaneous Tissue
1. The area most amenable to salvage by resuscitative and wound management techniques following thermal injury is called the: A. Zone of hyperemia. B. Zone of coagulation. C. Zone of stasis.
2. Initial treatment of extensive cellulitis without abscess is: A. Vancomycin. B. β-lactam. C. Linezolid. D. Clindamycin.
Answer: C
The management of thermal wounds is initially guided by the concept of three distinct zones of injury. The focus of ther­mal injury that has already undergone necrosis is known as the zone of coagulation. Well outside the zone of coagulation is the zone of hyperemia, which exhibits signs of inflamma­tion but will likely remain viable. In between these two zones is a zone of stasis with questionable tissue viability, and it is this area at which proper burn care can salvage viable tissue and decrease the extent of injury. (See Schwartz 11th ed., pp. 521–522.)
Answer: B
Extensive cellulitis is managed in a similar fashion as simple cellulitis. Initial treatment consists of intravenous antibiotics that cover β-hemolytic streptococcus, such as cephalospo­rins, with the addition of methicillin-resistant Staphylococcus aureus (MRSA) coverage if there is no improvement in symp­toms. Vancomycin is typically the first choice for MRSA cov­erage, but this drug is inferior to β-lactams for coverage of methicillin-sensitive S. aureus (MSSA). Alternative antibiotics that are typically effective against MRSA are linezolid, dapto­mycin, tigecycline, and telavancin. Clindamycin is approved for use against MRSA, but resistance rates are increasing, and its use is discouraged if institutional rates of clindamycin resis­tance are >15%. (See Schwartz 11th ed., p. 525.)
3. A 3-mm, nodular-type basal cell carcinoma (BCC) of the skin of the trunk should be treated with: A. Mohs micrographic surgery. B. Dermatologic laser vaporization. C. Excision with a 4-mm margin of normal tissue. D. Electrodesiccation.
Answer: C
Treatment of BCC varies according to size, location, type, and high or low risk. Treatment options include surgical exci­sion and medical or destructive therapies. Surgical excision should include 4 mm margins for low-risk lesions. Mohs microsurgical is indicated for high-risk lesions, especially in cosmetically sensitive areas. In high-risk lesions in which Mohs micrographic surgery is not available, excision with 10 mm margin of normal tissue can be considered. (See Schwartz 11th ed., p. 529.)
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4. The primary risk factor for the development of squa­mous cell carcinoma (SCC) is: A. Ultraviolet (UV) radiation exposure. B. Tobacco use. C. Exposure to chemical agents. D. Chronic, nonhealing wounds.
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5. Using the ABCDE initialism for melanoma, at what diameter does a nevus become concerning for malignant transformation? A. 2 mm
The Skin and Subcutaneous Tissue
B. 4 mm C. 6 mm D. 10 mm
6. What is the most common site of distant metastasis of cutaneous melanoma? A. Brain B. Lung C. Bone D. Distant skin
Answer: A
The primary risk factor for the development of SCC is UV radiation exposure; however, other risks include light Fitzpatrick skin type (I or II), environmental factors such as chemical agents, physical agents (ionizing radiation), pso­ralen, HPV-16 and -18 infections, immunosuppression, smok­ing, chronic wounds, burn scars, and chronic dermatoses. Heritable risk factors include xeroderma pigmentosum, epidermolysis bullosa, and oculocutaneous albinism. (See Schwartz 11th ed., p. 529.)
Answer: C
Melanoma most commonly manifests as cutaneous disease, and clinical characteristics of malignant transformation are often remembered by the initialism ABCDE. These lesions are typically asymmetric with irregular borders, color varia­tions, a diameter > 6 mm, and are undergoing some sort of evolution or change. Other key clinical characteristics include a pigmented lesion that has enlarged, ulcerated, or bled. Amelanotic lesions appear as raised pink, purple, or flesh­colored skin papules and are often diagnosed late. (See Schwartz 11th ed., p. 530.)
Answer: B
The most common sites of metastasis of melanoma are the lung and liver. These are followed by the brain, gastrointesti­nal tract, distant skin, and subcutaneous tissue. (See Schwartz 11th ed., p. 533.)
7. Which aggressive subtype of melanoma is characterized by an early vertical growth pattern, often leading to later­stage diagnosis? A. Superficial spreading B. Lentigo maligna C. Acral lentiginous D. Nodular
Answer: D
The most common subtype of melanoma is superficial spreading (Fig. 16-1). This accounts for 50% to 70% of mela­nomas and typically arises from a precursor melanocytic nevus. Nodular subtype accounts for 15% to 30% of melano­mas, and typically arises de novo, most commonly in men and on the trunk (Figs. 16-2 and 16-3). This subtype is aggressive with an early vertical growth pattern and is often diagnosed at a later stage. Up to 5% of these lesions will lack melanin and can be mistaken for other cutaneous lesions. Lentigo maligna represents 10% of melanoma cases and is a less aggressive subtype of melanoma in situ that typically arises on sun-exposed areas of the head and neck. Acral lentiginous
FIG. 16-1. Primary cutaneous melanoma seen in the scalp
of a 61-year-old man.
FIG. 16-2. Nodular melanoma seen in the leg of
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a 55-year-old man.
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melanoma accounts for 29% to 72% of melanomas in dark­skinned individuals, is occasionally seen in Caucasians, and is found on palmar, plantar, and subungual surfaces. This subtype is not thought to be due to sun exposure. (See Schwartz 11th ed., p. 530.)
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The Skin and Subcutaneous Tissue
A B
C
FIG. 16-3. A. AP view of advanced melanoma in a
59-year-old man. B. Lateral view. C. After resection and reconstruction with skin grafting.
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8. Which of the answer choices does NOT represent an indication for sentinel lymph node biopsy (SLNB) in the setting of malignant cutaneous melanoma? A. Breslow depth 0.5 mm with superficial ulceration B. Clinically positive lymph nodes C. Breslow depth 1.5 mm without superficial ulceration D. Breslow depth 1.0 mm with lymphovascular invasion
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The Skin and Subcutaneous Tissue
Answer: B
SLNB is a standard staging procedure to evaluate the regional nodes for patients with clinically node-negative malignant melanoma. Detecting subclinical nodal metasta­sis may benefit from lymphadenectomy or adjuvant therapy. This technique identifies the first draining lymph node from the primary lesion and has shown excellent accuracy and sig­nificantly less morbidity compared to complete resection of nodal basins. It is almost always performed at the time of ini­tial wide excision, as SLN mapping after lymphatic violation from surgical excision could decrease the accuracy of the test. Recently, the results of MSLT-1, an international, multicenter, phase III trial were published. This study randomized clini­cally node negative patients to either SLNB at the time of pri­mary melanoma excision (and completion lymphadenectomy if positive) or nodal basin monitoring (and delayed complete lymphadenectomy for recurrent lymph node disease). The results of this study demonstrated that SLNB, with immedi­ate lymphadenectomy if positive, improved disease-free sur­vival by 7% and 10% in patients with intermediate thickness (1.2–3.5 mm) and thick (>3.5 mm) lesions, respectively. The latest NCCN guidelines suggest consideration of SLNB in clinically stage I/II patients with Breslow depth > 1.0 mm or >0.8 mm with high-risk features (ulceration, mitotic index > 2/mm2, or lymphovascular invasion). A patient with clini­cally positive nodes would not be a candidate for screening SLNB. (See Schwartz 11th ed., p. 531.)
9. Which surgical margins are appropriate for excision of a primary cutaneous melanoma that has a Breslow depth of 1.5 mm? A. 5 mm margins B. 10 mm margins C. 30 mm margins D. 1.5 mm margins
10. What is the source of regenerative keratinocytes in the epithelialization of partial thickness wounds of the skin? A. Langerhans cell conversion to keratinocytes B. Fibroblast conversion to keratinocytes C. Extravasation of stem cells from the blood stream D. Keratinocytes from the lining of epidermal appendages
Answer: B
The appropriate excision margin for cutaneous melanoma is based on primary tumor thickness. Several retrospective studies suggest that for melanoma in situ, 0.5 to 1 cm mar­gins are sufficient. 1-cm margins should be obtained in ana­tomically feasible areas given the possibility of an incidental finding of a small invasive component in permanent sections. Several studies compared 1- to 3-cm margins and 2- to 5-cm margins in melanoma <2 mm thick, and 2- to 4-cm margins in melanoma lesions 1 to 4 mm thick and found no differ­ence. A British trial suggested that there is a limit to how narrow margins can be for melanomas >2 mm thick by show­ing that 1-cm margins provide worse outcomes compared to 3-cm margins. Tumors <1 mm thick require 0.5 to 1 cm mar­gins. Tumors 1 to 2 mm thick require 1 to 2 cm margins, and tumors >2 mm thick require 2-cm margins. (See Schwartz 11th ed., p. 532.)
Answer: D
The stratum basale, or germinative layer, is a deep, single layer of asynchronous, continuously replicating cuboidal to columnar epithelial cells and is the beginning of the life cycle of the keratinocytes of the epidermis. This layer is bound to its basement membrane by complexes made of keratin fila­ments and anchoring structures called hemidesmosomes. They are bound to other keratinocytes by structures called desmosomes. High mitotic activity and thus large nuclei and basophilic staining characterize the stratum basale on light microscopy. This layer also lines the epidermal appendages that reside largely within the substance of the dermis and later serves as a regenerative source of epithelium in the event of partial thickness wounds. (See Schwartz 11th ed., p. 514.)
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11. What cell type are characterized by rod- or racket­shaped Birbeck granules, takes up antigens for presenta­tion to T-cells, and makes up 3% to 6% of the cells of the epidermis? A. Langerhans cell B. Melanocyte C. Merkel cell D. Mast cell
12. What type of gland is typically influenced by sex hor­mones and undergoes a secretion process that involves decapitation of the part of the cell? A. Hair follicle B. Sebaceous gland C. Apocrine sweat gland D. Eccrine sweat gland
Answer: A
Of the cells in the epidermis, 3% to 6% are immune cells known as Langerhans cells. Typically found within the stratum spinosum, these mobile, dendritic cells interdigitate between keratinocytes of the epidermis to create a dense network, sampling any antigens that attempt to pass through the cutane­ous tissue. Through use of their characteristic rod- or racket­shaped Birbeck granules, they take up antigens for presentation to T-cells. These monocyte-derived cells represent a large part of the skin’s adaptive immunity. (See Schwartz 11th ed., p. 515.)
Answer: C
One type of sweat gland, known as the apocrine sweat gland, is found around the axilla, anus, areola, eyelid, and external auditory canal. The cells in this gland undergo an excretion process that involves decapitation of part of the cell. These apocrine glands are typically activated by sex hormones and thus activate around the time of puberty. The secretion from apocrine glands is initially odorless, but bacteria in the region may cause an odor to develop. Pheromone produc­tion may have been a function of the apocrine glands, but this may now be vestigial. While eccrine sweat glands are acti­vated by the cholinergic system, apocrine glands are activated by the adrenergic system. (See Schwartz 11th ed., p. 515.)
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The Skin and Subcutaneous Tissue
13. In the Hurley classification of hidradenitis suppurativa, which stage is characterized by diffuse disease with inter­connected sinus tracts and recurrent abscesses? A. Hurley stage IV B. Hurley stage III C. Hurley stage II D. Hurley stage I
14. What mucocutaneous disorder, thought to be a reaction to various drugs, is characterized by mucocutaneous destruction at the dermoepidermal junction affecting <10% of the cutaneous epithelium? A. Nikolsky syndrome B. Toxic epidermal necrolysis (TEN) C. Hidradenitis suppurativa D. Stephens-Johnson syndrome (SJS)
15. A 55-year-old otherwise healthy man presents 1 hour after a human bite to his hand. After thoroughly washing out the wound, are prophylactic antibiotics necessary? If so, what antibiotic regimen is most appropriate? A. No antibiotic prophylaxis indicated B. 3–7 days of cephalexin C. 3–7 days of amoxicillin/clavulanate D. 3–7 days of vancomycin and piperacillin/tazobactam
Answer: B
The diagnosis of hidradenitis is clinical, and the presentation is most commonly categorized by the Hurley classification system, divided into three stages. Single or multiple nodules or abscesses without any sinus tracts or scarring would be classified as stage I disease. As abscesses recur and sinus tracts and scarring form, the disease is classified as Hurley stage II. Stage III is the most advanced stage, with diffuse disease and interconnected sinus tracts and abscesses. Hurley stage IV is nonexistent. (See Schwartz 11th ed., p. 517.)
Answer: D
Epidermal necrolysis (EN) is a rare mucocutaneous disorder characterized by cutaneous destruction at the dermoepider­mal junction. EN is commonly referred to as either SJS or TEN depending on the extent of skin involvement present. SJS refers to cases in which <10% of total body surface area is involved, while cases with >30% involvement are consid­ered TEN, with an SJS-TEN overlap syndrome referring to all cases in between. A positive Nikolsky sign is often present, in which lateral pressure on the skin causes separation of the epidermis from the dermis. (See Schwartz 11th ed., p. 518.)
Answer: C
Bacteria colonizing human bites are those present on the skin or in the mouth. These include the gram-positive aerobic organisms Staphylococcus aureus, Staphylococcus epidermidis, and Streptococcus species, and anaerobes including Peptococ- cus species, Peptostreptococcus species, Bacteroides species, and Eikenella corrodens (facultative anaerobe). Human bites are characterized by a higher bacterial load (>105). Antibi­otic prophylaxis after a human bite is recommended as it has
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been shown to significantly decrease the rate of infection. A course of 3 to 7 days of amoxicillin/clavulanate is typically used. Alternatives are doxycycline or clindamycin with cipro­floxacin. (See Schwartz 11th ed., p. 519.)
16. Following caustic injury with a strong alkaline solution, what is the appropriate treatment? A. Neutralization with a weakly acidic solution for
CHAPTER 16
30 minutes B. Irrigation with normal saline for 30 minutes C. Irrigation with normal saline for 120 minutes D. Immediate coverage with light compressive dressing
The Skin and Subcutaneous Tissue
17. How long does it take to get irreversible tissue damage with external pressure greater than double capillary per­fusion pressure? A. 1 hour B. 2 hours C. 3 hours D. 4 hours
18. Pressure-induced ischemia to cutaneous tissue resulting in nonblanching erythema with intact epidermis repre­sents which stage of injury? A. Does not yet qualify as pressure-induced tissue injury B. Stage I C. Stage II D. Stage III
Answer: C
Treatment for acidic or alkaline chemical burns is first and foremost centered around dilution of the offending agent, typically using distilled water or saline for 30 minutes for acidic burns and 2 hours for alkaline injuries. Attempting to neutralize the offending agent is typically discouraged, as it does not offer an advantage over dilution and the neutraliza­tion reaction could be exothermic, increasing the amount of tissue damage. After removal of the caustic agent, the burn is treated like other burns and is based on the depth of tissue injury. (See Schwartz 11th ed., p. 521.)
Answer: B
The average perfusion pressure of the microcirculation is about 30 mm Hg, and pressures greater than that cause local tissue ischemia. In animal models, pressure greater than twice the capillary perfusion pressure produces irreversible tissue necrosis in just 2 hours. Tissues with a higher metabolic demand are typically susceptible to insult from tissue hypo­perfusion more rapidly than tissues with a lower metabolic demand. Because of this, it is possible to have muscle necrosis beneath cutaneous tissue that has yet to develop signs of irre­versible damage. (See Schwartz 11th ed., p. 523.)
Answer: B
Pressure ulcers can present in several ways depending on the stage at presentation. They are typically grouped into four stages: stage I, nonblanching erythema over intact skin; stage II, partial-thickness injury with blistering or exposed dermis; stage III, full-thickness injury extending down to, but not including, fascia and without undermining of adjacent tis­sue; and stage IV, full-thickness skin injury with destruction or necrosis of muscle, bone, tendon, or joint capsule. (See Schwartz 11th ed., p. 523.)
19. What type of necrotizing soft tissue infection (NSTI) is characterized by a monomicrobial source of β-hemolytic Streptococcus or Staphylococcus species? A. Type I B. Type II C. Type III D. Type IV
Answer: B
There are three types of NSTIs when classified by the offend­ing agent. The most common is type 1, which is caused by a polymicrobial source including gram-positive cocci, gram­negative rods, and anaerobic bacteria, specifically Clostridium perfringens and C. septicum. Type 2 is caused by a monomi­crobial source of β-hemolytic Streptococcus or Staphylococcus species, with methicillin-resistant Staphylococcus aureus (MRSA) contributing to the increasing number of community­acquired NSTIs. A history of trauma is often elicited and can be associated with toxic shock syndrome. Type III is a rare but fulminant subset resulting from a Vibrio vulnificus infec- tion of traumatized skin exposed to a body of salt water. (See Schwartz 11th ed., p. 525.)
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20. What subtypes of the human papilloma virus (HPV) confer the highest risk for malignancy? A. Types 16 and 18 B. Types 6 and 11 C. Types 6 and 8 D. Types 3 and 4
21. What cystic lesion is a benign, congenital occurrence caused by persistent epithelium across embryonic fusion lines, most commonly between the forehead and tip of the nose? A. Trichilemmal cyst B. Epidermoid cyst C. Dermoid cyst D. Nevus
Answer: A
Mucosal HPV types cause lesions in the mucosal or genital areas and behave like sexually transmitted infections. The most common mucosal types are HPV-6, -11, -16, -18, -31, and -33. These lesions present as condylomata acuminata, genital or veneral warts, papules that occur on the perineum, external genitalia, anus, and can extend into the mucosal sur­faces of the vagina, urethra, and rectum. These lesions are at risk for malignant transformation, with types 6 and 11 con­ferring low risk, and types 16, 18, 31, and 33 conferring a high risk. The recently developed quadrivalent HPV vaccine, tar­geting HPV types -6, -11, -16, and -18, is now available to both males and females age 9 to 26 and is associated with an up to 90% reduction of infections from those HPV types. (See Schwartz 11th ed., p. 526.)
Answer: C
Dermoid cysts are congenital variants that occur as the result of persistent epithelium within embryonic lines of fusion. They occur most commonly between the forehead and nose tip, and the most frequent site is the eyebrow. They can lie in the subcutaneous tissue or intracranially, and often com­municate with the skin surface via a small fistula. These cys­tic structures contain epithelial tissue, hair, and a variety of epidermal appendages. Treatment for these cystic structures includes surgical excision with care taken to remove the cyst lining to prevent recurrence. (See Schwartz 11th ed., p. 527.)
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The Skin and Subcutaneous Tissue
22. What subtype of basal cell carcinoma (BCC) is the most common, characterized by raised, pearly pink papules with telangiectasias and occasionally a depressed tumor center with raised borders? A. Micronodular B. Infiltrating C. Superficial spreading D. Nodular
Answer: D
There are multiple variants of BCC, and presentation can range from red, flesh-colored, or white macule or papule to nodules and ulcerated lesions. Growth patterns of these lesions can either be well-circumscribed or diffuse and the most common types of BCC are nodular and micronodu­lar, superficial spreading, and infiltrative. The most com­mon subtype is the nodular variant, characterized by raised, pearly pink papules with telangiectasias and occasionally a depressed tumor center with raised borders giving the clas­sic “rodent ulcer” appearance. Superficial spreading BCC is confined to the epidermis as a flat, pink, scaling or crusting lesion, often mistaken for eczema, actinic keratosis, fungal infection, or psoriasis. This subtype typically appears on the trunk or extremities and the mean age of diagnosis is 57 years. The infiltrative form appears on the head and neck in the late 60s, often at embryonic fusion lines, with an opaque yellow­white color that blends with surrounding skin and has no raised edges. The morpheaform subtype represents 2% to 3% of all BCC and is the most aggressive subtype. It usually pres­ents as an indurated macule or papule with the appearance of an enlarging scar. The clinical margins are often indistinct, and the rate of positive margins after excision is high. There is also a pigmented variant of BCC that can be difficult to distinguish from certain melanoma subtypes. (See Schwartz 11th ed., pp. 528–529.)
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23. Which of these skin lesions can represent a precursor lesion to squamous cell carcinoma? A. Seborrheic keratosis B. Actinic keratosis C. Congenital nevus D. Acrochordons
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The Skin and Subcutaneous Tissue
Answer: B
Actinic keratoses are neoplasms of epidermal keratinocytes that represent a range in a spectrum of disease from sun damage to squamous cell carcinoma. They typically occur in fair-skinned, elderly individuals in primarily sun-exposed areas, and ultraviolet (UV) radiation exposure is the great­est risk factor. There are multiple variants, and they can pres­ent as erythematous and scaly to hypertrophic, keratinized lesions. They can become symptomatic, causing bleeding, pruritus, and pain. They can regress spontaneously, persist without change, and transform into invasive squamous cell carcinoma. It is estimated that approximately 10% of actinic keratoses will transform into invasive squamous cell carci­noma, and that progression takes about 2 years on average. About 60% to 65% of squamous cell carcinomas are believed to originate from actinic keratoses. Congenital nevi can rarely transform into malignant melanoma. Seborrheic keratoses and acrochordons do not carry malignant potential. (See Schwartz 11th ed., p. 528.)
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Breast
1. Which of the following changes in the breast is not asso­ciated with pregnancy? A. Accumulation of lymphocytes, plasma cells, and
eosinophils within the breast B. Enlargement of breast alveoli C. Release of colostrum D. Accumulation of secretory products in minor duct
lumina
2. Which of the following statements is incorrect? A. Level I lymph nodes are those that are lateral to the
pectoralis minor muscle.
B. Level II lymph nodes are located deep to the pectora-
lis minor muscle.
C. Level Ill lymph nodes are located medial to the pecto-
ralis minor muscle.
D. Level IV lymph nodes are the ipsilateral internal
mammary lymph nodes.
Answer: C
With pregnancy, the breast undergoes proliferative and devel­opmental maturation. As the breast enlarges in response to hormonal stimulation, lymphocytes, plasma cells, and eosin­ophils accumulate within the connective tissues. The minor ducts branch and alveoli develop. Development of the alveoli is asymmetric, and variations in the degree of development may occur within a single lobule. With parturition, enlarge­ment of the breasts occurs via hypertrophy of alveolar epithe­lium and accumulation of secretory products in the lumina of the minor ducts. Alveolar epithelium contains abundant endoplasmic reticulum, large mitochondria, Golgi com­plexes, and dense lysosomes. Two distinct substances are pro­duced by the alveolar epithelium: (a) the protein component of milk, which is synthesized in the endoplasmic reticulum (exocrine secretion); and (b) the lipid component of milk (apocrine secretion), which forms as free lipid droplets in the cytoplasm. Milk released in the first few days after parturi­tion is called colostrum and has low lipid content but contains considerable quantities of antibodies. (See Schwartz 11th ed., p. 548.)
Answer: D
Axillary lymph node groups are as follows: Level I includes lymph nodes located lateral to the pectoralis minor muscle; level II includes lymph nodes located deep to the pectoralis minor; and level Ill includes lymph nodes located medial to the pectoralis minor. (See Schwartz 11th ed., p. 547.)
3. Concerning gynecomastia, which of the following is TRUE? A. During senescence gynecomastia is usually unilateral. B. During puberty gynecomastia is usually bilateral. C. Gynecomastia is associated with breast cancer in
Klinefelter syndrome patients.
D. Gynecomastia is classified as per a three-grade system.
Answer: C
In gynecomastia, the ductal structures of the male breast enlarge, elongate, and branch with a concomitant increase in epithelium. During puberty, the condition often is unilateral and typically occurs between ages 12 and 15 years. In con­trast, senescent gynecomastia is usually bilateral. Gynecomas­tia generally does not predispose the male breast to cancer. However, the hypoandrogenic state of Klinefelter syndrome (XXY), in which gynecomastia is usually evident, is associ­ated with an increased risk of breast cancer. Gynecomastia is graded based on the degree of breast enlargement, the position
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