25 The Skin
1 For the past decade, a 29-year-old man has had waxing and waning of the lesions shown in the figure. The scalp, lumbosacral region, and glans penis also are affected. For the past 2 years, he has had chronic arthritis in the hips and knees. Which of the following physical findings would most likely be present in this patient?
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(E) 2 An epidemiologic study is conducted to identify factors that increase the risk of skin cancer. The study documents subjects reported to tumor registries with a diagnosis of malignant melanoma and the incidence of melanoma worldwide over the past 25 years. Demographic information is collected. Analysis of the data is most likely to show the greatest increase in incidence of malignant melanoma in which of the following locations?
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(E) 3 A 64-year-old man has noted changes in the texture and color of skin in his armpit and groin over the past 3 months. On physical examination, there is thickened, darkly pigmented skin in the axillae and flexural areas of the neck and groin. These areas are neither painful nor pruritic. A punch biopsy specimen of axillary skin shows undulating epidermal acanthosis with hyperkeratosis and basal layer hyperpigmentation. Which of the following underlying diseases is most likely to be present in this patient?
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(E) 4 A 51-year-old man noticed a change in the skin lesion on the upper, outer area of his right arm, shown in the figure. The lesion has enlarged during the past month. Physical examination yields no other remarkable findings. Which of the following occupations is this man most likely to have had earlier in life?
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(E) 5 A 35-year-old man has had an outbreak of pruritic lesions over the extensor surfaces of the elbows and knees during the past month. He has a history of malabsorption that requires him to eat a special diet, but he has had no previous skin problems. On physical examination, the lesions are 0.4- to 0.7-cm vesicles. A 3-mm punch biopsy of one of the lesions over the elbow is performed. Microscopic examination of the biopsy specimen shows accumulation of neutrophils at the tips of dermal papillae and formation of small blisters owing to separation at the dermoepidermal junction. Immunofluorescence studies performed on this specimen show granular deposits of IgA localized to tips of dermal papillae. Laboratory studies show serum antigliadin antibodies. What is the most likely diagnosis?
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(H) 6 Over the course of 1 week, a 6-year-old boy develops 1- to 2-cm erythematous macules and 0.5- to 1-cm pustules on his face. During the next 2 days, some of the pustules break, forming shallow erosions covered by a honey-colored crust. New lesions form around the crust. The boy’s 40-year-old uncle develops similar lesions after visiting for 1 week during the child’s illness. Removal of the crusts from the boy’s face is followed by healing within 1 week. The uncle does not seek medical care, and additional pustules form at the periphery of the crusts. Which of the following conditions most likely explains these findings?
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(H) 7 A 50-year-old woman has been bothered by a discolored area of skin on her forehead that has not faded during the past 3 years. On physical examination, there is a 0.8-cm red, rough-surfaced lesion on the right forehead above the eyebrow. A biopsy specimen examined microscopically shows basal cell hyperplasia. Some of the basal cells show nuclear atypia associated with marked hyperkeratosis and parakeratosis with thinning of the epidermis. The upper dermal collagen and elastic fibers show homogenization with elastosis. What is the most appropriate advice to give this patient?
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(E) 8 A 10-year-old girl is brought to the physician by her mother because multiple excoriations have appeared on the skin of her hands over the past week. The child reports that she scratches her hands because they itch. Physical examination shows several 0.2- to 0.6-cm linear streaks in the interdigital regions. Treatment with a topical lindane lotion resolves the condition. Which of the following organisms is most likely responsible for these findings?
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(E) 9 A 35-year-old man has noted a bump on his upper trunk for the past 6 weeks. On physical examination, there is a solitary, 0.4-cm, flesh-colored nodule on the upper trunk. The dome-shaped lesion is umbilicated, and a curdlike material can be expressed from the center. This material is smeared on a slide, and Giemsa stain shows many pink, homogeneous, cytoplasmic inclusions. The lesion regresses over the next 2 months. Which of the following infectious agents most likely produced this lesion?
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(E) 10 Many skin disorders give rise to vesicles or bullae (blisters) in the skin. The location of the bulla often aids in the diagnosis. What disorder is most likely to produce the type of blister that is schematically illustrated in the figure?
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(E) 11 A 39-year-old woman has a nodule on her back that has become larger over the past 2 months. On physical examination, there is a 2.1-cm pigmented lesion with irregular borders and an irregular brown-to-black color. An excisional biopsy with wide margins is performed, and microscopic examination of the biopsy specimen shows a malignant melanoma composed of epithelioid cells that extends 2 mm down to the reticular dermis. There is a band of lymphocytes beneath the melanoma. Which of the following statements is most appropriate to make to this patient regarding these findings?
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(E) 12 A 39-year-old woman goes to her dentist for a routine checkup. The dentist notes that she has 0.2- to 1.5-cm scattered, white, reticulated areas on the buccal mucosa. The woman says that these lesions have been present for 1 year. She also has some 0.3-cm purple, pruritic papules on each elbow. A biopsy specimen of a skin lesion shows a bandlike infiltrate of lymphocytes at the dermal-epidermal junction and degeneration of basal keratinocytes. What is the best advice to give this patient regarding these lesions?
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(E) 13 A 22-year-old man and other members of his racquetball club have noticed more itching of their feet in the past 2 months. On physical examination, the man has diffuse, erythematous, scaling skin lesions between the toes of both feet. There are no other remarkable findings. These findings are most likely the result of infection with which of the following organisms?
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(J) 14 Over the past 20 years, a 75-year-old man has noticed slowly enlarging lesions, similar to those shown in the figure, on his trunk. One of the lesions is excised, and microscopic examination shows sheets of lightly pigmented basaloid cells that surround keratin-filled cysts. This lesion is sharply demarcated from the surrounding epidermis. What is the most likely diagnosis?
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(H) 15 A 30-year-old man is known for his large appetite. At a luncheon meeting, he notices that all the cookies contain nuts, which the other diners have ordered knowing that he would not eat them because he would develop blotchy erythematous, slightly edematous, pruritic plaques on his skin. These plaques would form and then fade within 2 hours. If the man eats the cookies, which of the following sensitized cells would release a mediator that produces these skin lesions?
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(E) 16 A 17-year-old girl has hundreds of skin lesions on her body that have been forming since childhood. On physical examination, 0.4- to 1.7-cm, macular to slightly raised, plaquelike, dark brown pigmented lesions are present on sun-exposed and non–sun-exposed areas of skin. The lesions have irregular contours, and there is variability in pigmentation. She says that her 15-year-old brother has similar lesions. Which of the following molecular changes are most likely to be present in the DNA from this patient?
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(F) 17 A 60-year-old man has noted the appearance of a nodule on his ear during the past month. On physical examination, there is a 1.2-cm, flesh-colored, dome-shaped nodule on his right ear lobe. The nodule has a central keratin-filled crater surrounded by proliferating epithelium. The lesion regresses and disappears within 1 month. What is the most appropriate diagnosis of this lesion?
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(F) 18 A 68-year-old man visits the physician because of a slowly enlarging nodule on his right eyelid. On physical examination, there is a 0.3-cm pearly nodule on the upper eyelid near the lateral limbus of the right eye. The lesion is excised, but multiple frozen sections are made during the surgery to minimize the extent of the resection and preserve the eyelid. The microscopic appearance of the lesion is shown at low magnification in the figure. What is the most likely diagnosis?
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(E) 19 A 5-year-old girl is brought to the physician by her parents for a routine health checkup. On physical examination, she has scattered 1- to 3-mm, light brown macules on her face, trunk, and extremities. The parents state that these macules become more numerous in the summer months, but fade over the winter. The lesions do not itch, bleed, or hurt. What is the most likely diagnosis?
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