Derma Channel (OSCE slides, lectures, MCQs and discussion)

middle-aged man presents with a growth on his right ear that has been present for over a year. The patient reports that the lesion has been growing slowly and occasionally bleeds. Physical examination reveals a group of erythematous papules in the triangular fossa of the right ear . A shave biopsy of the ear lesion was performed. Histologic examination of the biopsy specimen reveals a polypoid vascular lesion with lymphocytes and numerous eosinophils . The endothelial cells appeared swollen and focally showed fenestration . Further immunohistochemistry studies were conducted. ERG and CD34 stains highlight the endothelial cells , while the HHV-8 stain was negative. What is the most likely diagnosis? A- Eosinophilic granuloma B- Pyogenic granuloma C- Basal cell carcinoma D- Angiolymphoid hyperplasia with eosinophilia

28-year-old woman presents with recurrent, painless patches on her tongue. She notes that the patches have flared intermittently over years. The patches seem to change in size, shape, and location over several days, sometimes migrating to different parts of the tongue. She denies bleeding or ulceration, but reports occasional mild sensitivity with spicy or acidic foods during flares. She has no significant past medical history and is not taking any medications. She does not use tobacco and has no known dermatologic history aside from mild atopy.  On physical examination, there are multiple, well-demarcated, erythematous, smooth patches on the dorsal tongue with serpiginous, slightly raised white borders (Figure). The lesions vary in size and distribution. The surrounding mucosa is normal, without induration, ulceration, or evidence of secondary infection.What is the most likely diagnosis? A- Candidiasis B- Erythroplakia C- Lichen planus D- Migratory glossitis

A 42-year-old woman presents to the dermatology clinic for evaluation of progressive skin discoloration. She reports gradually developing light patches on her hands and around her mouth over the past year. The areas are asymptomatic, though she notes occasional mild pruritus. She denies a preceding rash, trauma, or new topical exposures. Her history is notable for autoimmune thyroid disease. Physical examination reveals multiple well-demarcated depigmented macules and patches on the dorsal hands and perioral region. Some areas demonstrate leukotrichia within the patches. There is no scale, erythema, or induration. QUESTION What is the most likely diagnosis? A- Nevus depigmentosus B- Vitiligo C- Tinea (pityriasis) versicolor D- Progressive macular hypomelanosis

76-year-old man presents to the dermatology clinic for evaluation of 2 firm lesions on his left ear. He reports first noticing them several months ago, with no change in size. The lesions are asymptomatic and without pain, pruritus, bleeding, or prior trauma. The patient has a history of significant sun exposure. His past medical history is unremarkable. Physical examination reveals well-circumscribed, firm, subcutaneous nodules on the helix of the left ear, each measuring a few millimeters in diameter. The overlying skin is intact without erythema, scale, or ulceration, and the lesions are non-tender. The remainder of the skin examination is un remarkable.What is the most likely diagnosis? A- Keloid B- Basal cell carcinoma C- Weathering nodule D- Seborrheic keratosis

45-year-old Black man presents for evaluation of residual skin changes on the right side of his torso. He reports that approximately 2 months ago, he developed a sudden-onset, intensely pruritic rash in this area that gradually spread across the right lateral chest and abdomen. The eruption has since improved without treatment, but he notes persistent dark marks where the rash had been. He denies pain, fever, recent illness, new medications, or new topical exposures. His past medical history is unremarkable. Physical examination reveals multiple hyperpigmented macules and patches arranged in 2 separate linear bands along the right lateral chest and abdomen. The bands follow a curvilinear pattern, remain confined to the right side without crossing the midline, and are separated by a strip of normal-appearing skin. The remainder of the skin examination is unremarkable. What is the most likely diagnosis? A-Purpura B- Lichen planus C- Blaschkitis D- Eczema

A 73-year-old White man presents for evaluation of gradually progressive facial skin changes. He reports that over the past several years, he has noticed an increasing number of “blackheads” and small bumps around his eyes and upper cheeks. The lesions do not cause pain, pruritus, or drainage. His past medical history is notable for hypertension, and he reports a 40-pack-year smoking history. He worked as a farmer for over 40 years and rarely used sun protection. Physical examination reveals numerous open comedones and cystic papules clustered symmetrically over the periorbital and zygomatic regions bilaterally. The surrounding skin appears thickened, yellowish in hue, and with prominent wrinkling. The lesions are non-tender and without surrounding erythema or inflammation. No similar findings are noted on the chest or back. The remainder of the skin examination is unremarkable. What is the most likely diagnosis? A-Milia B- Acne C- Favre-Racouchot D- Colloid milia

A 35-year-old man presents to the dermatology clinic for evaluation of a skin lesion on his right calf. He reports noticing the bright red spot approximately 8 months ago and has remained the same size. He also noted a few similar spots on his trunk. All of the lesions are entirely asymptomatic and have never bled. His medical history is unremarkable, and he takes no daily medications. On physical examination, the skin of the right calf reveals a well-demarcated, dome-shaped, bright red-colored papule. Examination of the trunk reveals a few similar 1 mm to 5 mm vascular proliferations. What is the most likely diagnosis? A- Lobular capillary B- hemangioma C- Pyogenic granuloma Cherry angioma Glomeruloid hemangioma

24-year-old woman presents for evaluation of a persistent, itchy rash on her right arm. She reports that over the past several months, she has noticed a dry, irritated patch in the crease of her right elbow. The lesion is associated with intense pruritus, which frequently leads to repeated scratching. She notes that the redness and itching are significantly exacerbated after taking long, hot showers. She denies any spontaneous hives, spreading of the rash, pain, or systemic symptoms. Her medical history is notable for childhood asthma and seasonal allergic rhinitis, but she is not currently taking any daily medications. Clinical evaluation of the right antecubital fossa reveals a poorly defined erythematous plaque with lichenification and scaling. Excoriations are present within the plaque, corresponding to the patient’s reported pruritus. No vesicles, weeping, or purpura are noted. The remainder of the skin examination is notable for generalized mild xerosis but otherwise unremarkable. What is the most likely diagnosis? A- Allergic contact dermatitis B- Atopic dermatitis C- Psoriasis vulgaris D- Tinea corporis

24-year-old woman presents for evaluation of a persistent, itchy rash on her right arm. She reports that over the past several months, she has noticed a dry, irritated patch in the crease of her right elbow. The lesion is associated with intense pruritus, which frequently leads to repeated scratching. She notes that the redness and itching are significantly exacerbated after taking long, hot showers. She denies any spontaneous hives, spreading of the rash, pain, or systemic symptoms. Her medical history is notable for childhood asthma and seasonal allergic rhinitis, but she is not currently taking any daily medications. Clinical evaluation of the right antecubital fossa reveals a poorly defined erythematous plaque with lichenification and scaling. Excoriations are present within the plaque, corresponding to the patient’s reported pruritus. No vesicles, weeping, or purpura are noted. The remainder of the skin examination is notable for generalized mild xerosis but otherwise unremarkable. What is the most likely diagnosis? A- Allergic contact dermatitis B- Atopic dermatitis C- Psoriasis vulgaris D- Tinea corporis

45-year-old man presents to the dermatology clinic for evaluation of a non-healing skin lesion on his chin. He reports that the spot has been slowly growing over the past 3 years and occasionally bleeds. It used to be a small bump that would only bleed after he shaved, but now it bleeds on its own. He has a history of significant cumulative sun exposure, specifically noting intense, blistering sunburns during his childhood and adolescence. On physical examination, there is a solitary, 4 cm exophytic pink papule with prominent telangiectasias located on the chin. A skin biopsy is performed, demonstrating a proliferation of mutated basaloid cells extending from the epidermis and invading into the local dermal tissue. What is the most likely diagnosis? A- Basal cell carcinoma B- Squamous cell carcinoma C- Melanoma D- Wart

57-year-old man presents to the dermatology clinic for evaluation of skin changes on his upper and lower extremities. He reports that over the past several weeks, he has noticed hyperpigmented, crusted, papular lesions associated with significant pruritus, leading to frequent scratching. His medical history is significant for end-stage renal disease (ESRD), for which he is receiving hemodialysis; heart failure; hypertension, coronary artery disease; and type 2 diabetes mellitus. On examination, the skin of the upper and lower extremities reveals scattered hyperpigmented, crusted papules and nodules. Closer inspection of the lesions reveals distinct central keratotic plugs. Excoriations are present in the affected areas. No vesicles, scale, or purpura are noted. The remainder of the skin examination is unremarkable. What is the most likely diagnosis? A- Pemphigoid B- Prurigo nodularis C- Dermatofibromas D- Acquired perforating dermatosis

24-year-old woman presents for evaluation of transient skin changes on her right thigh. She reports that over the past several months, she has noticed raised, linear marks appearing shortly after scratching or rubbing the area, particularly after shaving or wearing tight clothing.  The lesions are associated with pruritus and typically resolve spontaneously within 30 to 60 minutes, leaving no residual discoloration. She denies spontaneous hives, angioedema, pain, or systemic symptoms. Her medical history is unremarkable, and she is not taking any medications. On examination, the skin of the right thigh appears normal at rest. After gentle scratching of the skin with a blunt object, linear erythematous wheals develop along the areas of contact within several minutes, corresponding to the patient’s symptoms (Figure). No vesicles, scale, or purpura are noted. What is the most likely diagnosis? A- Dermatographism B- Telangiectasia C- Contact dermatitis D- Chronic urticaria

A68-year-old man is referred for evaluation of a scalp lesion that was first noted several weeks ago and has been gradually enlarging in size. The lesion bleeds when traumatized by combing. He has fair skin and admits to ample past sun exposure. A year ago, several actinic keratoses on his hands were treated cryosurgically. Examination reveals a 1.8 cm firm, slightly erythematous nodule. Cervical lymph nodes are nonpalpable. What is the likely diagnosis? A-Nodular basal cell carcinoma B-Atypical fibroxanthoma C-Amelanotic melanoma D-Schwannoma

A 42-year-old woman presented to the emergency department with anaphylaxis shortly after participating in a polar plunge challenge earlier that day. She mentioned that she had experienced several episodes of recurring, unexplained hives on her skin shortly after cold exposures for the past year. The patient’s medical history was uneventful. A cold stimulation test revealed a markedly edematous plaque with surrounding erythema after application of an ice cube. What's the diagnosis? A- Cold urticaria. B- Mast cell activation syndrome. C- Physical urticaria. D- Raynaud phenomenon.

43-year-old man presents for evaluation of a persistent skin discoloration on his left lower leg. He reports that the lesion has been present for approximately 8 months and has remained relatively stable in size and appearance. He denies pain, ulceration, or bleeding, although he notes occasional mild pruritus. He does not recall preceding trauma, infection, or new medication use. He has no significant past medical history and denies systemic symptoms. On examination, there is a solitary, well-demarcated, golden-brown to rust-colored patch on the medial aspect of the left lower leg measuring approximately 2 cm in diameter. The lesion has a smooth surface without scale, induration, or atrophy. No palpable purpura or surrounding erythema is present. There are no similar lesions elsewhere on the body. The remainder of the skin examination is unremarkable. What is the most likely diagnosis? A- Lichen aureus B- Schamberg disease C- Pityriasis rubra pilaris D- Mycosis fungoides

A 49-year-old man visited his doctor about a pruritic skin lesion that developed on his hand a few weeks prior. On dermatologic examination, a macerated plaque with peripheral peeling scale was seen at the finger web on his right hand. The patient worked as a dishwasher and had a history of diabetes mellitus. He appeared well and reported no systemic symptoms. Potassium hydroxide (KOH) examination showed the presence of yeasts. What's the diagnosis? A- Chromoblastomycosis B- Erosio interdigitalis blastomycetica C- Majocchi granuloma D- Tinea manus

24-year-old woman presents for evaluation of a skin lesion on her right thumb. She reports noticing the discoloration several days after returning from a vacation to the Caribbean. During the trip, she frequently prepared and drank margaritas while spending time outdoors in direct sunlight, and recalls handling fresh limes. She denies any trauma, pain, pruritus, or prior similar eruptions. She also denies fever or other systemic symptoms and has no history of photosensitive skin disorders. On examination, there is a well-demarcated, irregularly shaped, hyperpigmented patch on the dorsal aspect of the right thumb with a subtle linear and geometric configuration. There is no associated erythema, vesiculation, blistering, scaling, or ulceration. The surrounding skin appears normal, and the remainder of the skin examination is unremarkable What is the most likely diagnosis? A- Phytophotodermatitis B- Eczema C- Idiopathic guttate hypomelanosis D- Tinea

Weekly Challenge: A patient presented multiple erythematous papules and nodules, many crusted, in a primarily truncal distribution. A 24-year-old man visited his doctor with fever, joint pain, and painful cyst-like lesions that were progressive for the preceding few weeks. On dermatologic examination, there were multiple erythematous papules and nodules, many crusted, in a primarily truncal distribution that covered his neck, back, and chest. When asked about medications and drug use, the patient admitted that he had been taking anabolic-androgenic steroids (AAS) / testosterone for 5 months prior to lesion presentation. What's the diagnosis? A- Acne fulminans B- Acne vulgaris C- Folliculitis D- PFAPA syndrome

A 77-year-old man presents for evaluation of a chronic skin lesion on his right lower leg. He first noticed the lesion several years ago, with very gradual enlargement over time. He denies rapid growth, bleeding, ulceration, or significant pain, although he notes occasional mild pruritus. His medical history is notable for a squamous cell carcinoma on the left forearm that was excised 1 year ago without recurrence. He has a history of long-term sun exposure related to outdoor work and denies systemic symptoms. On examination, there is an annular, well-demarcated plaque on the anterior aspect of the right lower leg measuring approximately 1.5 cm in diameter. The lesion demonstrates a thin, raised, hyperkeratotic peripheral ridge with central hypopigmentation and mild atrophy. The border has a subtle brownish scale and is more prominent than the center. No ulceration, nodularity, or surrounding erythema is present. No similar lesions are identified elsewhere on the skin, and the remainder of the skin examination is unremarkable. What is the most likely diagnosis? A- Psoriasis B- Nummular eczema C- Porokeratosis D- Tinea