A 55-year-old man from China presents with a 3-month history of scales on his skin. Physical examination reveals numerous scaly, pigmented plaques, which rub off easily. Biopsy of a plaque shows anastomosing cords of mature and stratified squamous epithelium, associated with small keratin cysts. This patient may have which of the following underlying conditions?
An 18-year-old woman notes that one of her moles has increased in size and become darker. The patient has a family history of melanoma, and she is seen by her dermatologist regularly to "follow her moles." Physical examination reveals numerous, 5-10 mm, darkly pigmented, variegated lesions distributed primarily on her trunk but also involving non-sun-exposed skin. This patient may harbor a germline mutation in a gene that regulates which of the following proteins?
(C)
An 80-year-old farmer presents with a 1-cm, red, slightly raised plaque on his face. A biopsy of the lesion shows cytologic atypia and dyskeratosis limited to the basal layers of the stratum spongiosum, as well as hyperkeratosis and parakeratosis. This lesion is a precursor for which of the following dermatologic diseases?
45-year-old man presents with painful, purple nodules on the dorsal surface of his left hand that he first noticed 9 months ago. A biopsy (shown int he image) discloses a poorly demarcated lesion composed of atypical spindle-shaped neoplastic cels and extravasated red cells. Similar lesions are found in the lymph nodes and liver. Which of the following viruses is associated with the pathogenesis of this skin lesions?
(B)
A 70-year-old woman presents with facial discoloration. The patient is observed to have a flat, pigmented lesion on the atrophic, sun-damaged skin (shown in the image). Which of the following is the most likely diagnosis?
(E)
A 25-year-old man presents with a 1-month history of fatigue, mild fever, and an erythematous scaling rash. His major concern is related to the scaling plaques distributed on his knees, buttocks, elbows, scalp, and feet. He also notes some joint pain and swelling, primarily involving the small bones of his fingers. Physical examination reveals erythematous plaques with adherent silvery scales that induce punctate bleeding points when removed. Biopsy of lesional skin would most likely show an accumulation of which of the following cells in the epidermis?
(D)
Examination of a 2-day-old neonate reveals numerous blisters on the trunk and extremities. Skin biopsy discloses separation of the basal layer of the epidermis from its basement membrane and is devoid of inflammatory cells. No antibody deposits are identified by immunofluorescence microscopy. Which of the following is the most likely diagnosis?
(C)
A 25-year-old man complains of eruptions of blisters on his scalp and inner surface of the groin and in his mouth. The blisters rupture easily and leave large crusted areas. Histologically, the lesions show separation of the stratum spinosum from the basal layer. The results of direct immunofluorescence microscopy for IgG are shown. Which of the following proteins is targeted by IgG autoantibody in the skin of this patient?
(C)
A 60-year-old former lifeguard presents with several small, pearly nodules on the back of her neck. A biopsy of one of the nodules (shown in the image) reveals buds of atypical, deeply-basophilic keratinocytes extending from the overlying epidermis into the papillary dermis. Which of the following is the appropriate diagnosis?
(C)
A 10-year-old girl presents with multiple papules on the back of her hand that bleed easily. Histologic examination of a lesion reveals squamous epithelial-lined fronds with fibrovascular cores (shown in the image). Which of the following viruses is most likely responsible for the development of these skin lesions?
(E)
A 28-year-old woman presents with a 2-day history of dome-shaped erythematous nodules appearing on her skin. She recently had a urinary tract infection for which she was treated with trimethoprim sulfamethoxazole (Bactrim). Biopsy discloses focal hemorrhage, neutrophilic infiltrates in the subcutaneous fibrous tissue septa, and giant cells at the interface between the septa and the adipose fat tissue. No infectious agents are identified. Which of the following is the most likely diagnosis?
(E)
A 65-year-old woman complains of having an itchy rash for the past few months. She said the lesions first appeared as red swollen plaques on her abdomen and flexor aspect of her forearms. Physical examination reveals urticarial plaques, as well as large bullae on her abdomen and thighs (shown in the image). A skin biopsy shows a positive direct immunofluorescence test for IgG antibasement membrane antibody. Which of the following is the appropriate diagnosis?
(A)
A 15-year-old girl complains of itchy skin lesions of 6 months in duration. Physical examination reveals numerous wheal-like lesions with small vesicles over her elbows and knees. A skin biopsy demonstrates inflammation in the tips of the dermal papillae and subepidermal vesicles. Which of the following histopathologic findings would provide the best evidence to support a diagnosis of dermatitis herpetiformis in this patient?
(D)
A 17-year-old woman is brought to the physician by her parents because “she has been acting strangely” for a couple of days. Over the past 3 months, she has experienced malaise, joint pain, weight loss, and sporadic fever. The patient appears agitated, with a temperature of 38°C (101°F). Other physical findings include malar rash, erythematous-pink plaques with telangiectatic vessels, oral ulcers, and nonblanching purpuric papules on her legs. Laboratory studies show elevated levels of BUN and creatinine. The anti–double-stranded DNA antibody test is positive. Biopsy of sun-damaged lesional skin would most likely show which of the following histopathologic findings in this patient?
(B)
A 14-year-old boy presents with a 6-month history of erythematous papules on his face. Physical examination reveals numerous “blackheads” over the forehead and cheeks. Which of the following bacteria is associated with the development of these lesions?
(D)
A 30-year-old man presents with flat-topped papules that have appeared gradually on the flexor surfaces of his wrists. White streaks and patches are also found on the buccal mucosa of the patient’s mouth. Histologically, the lesions showed hyperkeratosis, thickening of the stratum granulosum, and a band-like infiltrate of lymphocytes and macrophages in the upper dermis, disrupting the basal layer of the epidermis. Lymphocytes were mostly of the CD4+ immunophenotype. Which of the following is the appropriate diagnosis?
(B)
A 66-year-old woman presents with a 5-year history of erythematous, scaly patches on her buttocks. Physical examination reveals plaques with telangiectases, atrophy, and pigmentation. Biopsy of lesional skin shows that the epidermis and papillary dermis are expanded by an extensive infiltrate of atypical lymphocytes. These infiltrating lymphocytes most likely express which of the following “cluster of differentiation” cell surface markers?
(A) CD4
(B) CD9
(C) CD15
(D) CD20
(E) CD31
A (Mycosis Fungoides)
A 30-year-old woman with chronic hepatitis B presents with numerous red skin lesions that she has had for 5 days. Physical examination reveals multiple, purpuric, 2- to 4-mm papules on the skin (shown in the image). The papules did not blanch under pressure. Biopsy of lesional skin shows necrotizing leukocytoclastic venulitis. Immunofluorescence studies disclose immune complex deposition in vascular walls. Which of the following is the most likely diagnosis?
A 20-year-old man presents to his family physician for treatment of itching after exposure to poison ivy. The patient’s hands and arms appeared red and were covered with oozing blisters and crusts (shown in the image). Which of the following the represents the most important step in the pathogenesis of sensitization phase of injury in this patient?
(E)
A 12-year-old girl presents for a routine physical examination. The patient has numerous freckles over her upper trunk and face. Which of the following terms best describes the morphologic appearance of her freckles?
(A)
A 40-year-old woman complains that the skin on her fingers feels stiff. The skin of her face appears tense, and radial furrows are evident around the mouth. A skin biopsy shows loss of dermal appendages and abundant collagen bundles aligned parallel to an atrophic epidermis. Which of the following clinical symptoms is commonly seen in patients with this dermatologic condition?
