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

71-year-old man presents with localized pain along the lateral aspect of his right fourth finger after working in the yard several months ago. He recalls a brief, sharp injury at the time and reports persistent tenderness since then, particularly when gripping objects or applying pressure to the area. He notes mild swelling but denies drainage, numbness, fever, or other systemic symptoms. His tetanus immunization status is uncertain.On physical examination, there is focal erythema and mild edema along the lateral side of the distal right fourth digit. There is also light brown linear discoloration beneath the skin surface. The area is tender to palpation without fluctuance or purulence. Sensation, capillary refill, and range of motion of the digit are intact. The remainder of the examination is unremarkable. What is the most likely diagnosis? A- Acute bacterial paronychia B- Felon (subcutaneous digital pulp infection) C- Cellulitis of the finger D- Retained cutaneous foreign body (splinter)

A 38-year-old woman presents with several weeks of asymptomatic discoloration on her shoulders and upper back. She first noticed faint light patches that gradually became more noticeable, particularly after sun exposure. She denies pain or pruritus but reports mild flaking when the areas are rubbed. She has no recent illness and denies use of new topical products or medications. She notes increased sweating during the summer months. On physical examination, multiple pinkish-white, oval-to-round, thin plaques are distributed symmetrically over the shoulders and upper back . The lesions have a thin, fine scale that becomes more apparent with gentle scraping. No erythema, induration, or excoriations are present. The remainder of the skin examination is unremarkable. What is the most likely diagnosis? A- Tinea versicolor B- Pityriasis alba C- Vitiligo D- Seborrheic dermatitis

A 41-year-old woman presents for evaluation of a pigmented lesion on the left side of her torso that has been present since birth. She reports that the lesion has enlarged proportionally with her body, slowly darkened slightly, and become slightly raised over time. She does not recall any recent rapid growth, bleeding, ulceration, pain, or pruritus. There is no personal or family history of skin cancer, and she reports no neurologic or systemic symptoms. On examination, there is a well-circumscribed, asymmetrically pigmented plaque on the left lateral torso measuring approximately 8 cm. The lesion shows variegated brown pigmentation with mild surface texture. No nodules, ulceration, or surrounding satellite lesions are noted. The remainder of the skin examination is unremarkable. What is the most likely diagnosis? A- Epidermal nevus B- Pigmented seborrheic keratosis C- Congenital nevus D- Melanoma

An 84-year-old woman with no significant past medical history presents for routine dermatologic evaluation; her last total body skin examination was 3 years earlier. She denies any personal or family history of skin cancer. Physical examination reveals a 1 x 1 cm papule with focal pigmentation on the right buttock. Dermoscopy shows a well-circumscribed, flesh-colored papule with blue-black pigmentation, surrounded by translucent-pink areas with telangiectatic vessels. There is no evidence of keratinization or scaling . What is the most likely diagnosis? A- Basal cell carcinoma B- Pigmented trichoblastoma C- Intradermal nevus D- Neurofibroma

An 84-year-old woman with no significant past medical history presents for routine dermatologic evaluation; her last total body skin examination was 3 years earlier. She denies any personal or family history of skin cancer. Physical examination reveals a 1 x 1 cm papule with focal pigmentation on the right buttock. Dermoscopy shows a well-circumscribed, flesh-colored papule with blue-black pigmentation, surrounded by translucent-pink areas with telangiectatic vessels. There is no evidence of keratinization or scaling . What is the most likely diagnosis? A- Basal cell carcinoma B- Pigmented trichoblastoma C- Intradermal nevus D- Neurofibroma

A 28-year-old collegiate rugby player visited his doctor about a bulging growth that he first noticed on his ear shortly after a rugby injury 2 months prior. On dermatologic examination, a misshapen, folded, nodular appearance of the upper ear was seen. What's the diagnosis? A- Cauliflower ear B- Keloid C- Pseudocyst of auricle D- Weathering nodules of ear

A 17-year-old adolescent presents with a several-month history of recurrent bumps on her forehead, cheeks, and chin. The lesions initially appeared as small skin-colored or slightly red bumps but have gradually increased in number. Over the past few weeks, some have become tender, especially before her menstrual cycle. She notes mild oiliness of the skin but denies using any new skincare products, cosmetics, or hair products. She has no history of similar eruptions as a child. Her medical history is unremarkable, and she is not taking any medications. She reports no recent illness, weight changes, headaches, or signs of hormonal imbalance such as hirsutism or irregular periods. On physical examination, multiple closed and open comedones are scattered across the forehead and both cheeks. Several small erythematous papules and a few superficial pustules are also present along the jawline. There are no nodules or cystic lesions. The surrounding skin shows mild sebaceous prominence but no significant erythema outside the affected areas. Examination of the chest and upper back reveals a few scattered comedonal lesions but no deeper inflammatory nodules. Mild scarring and post-inflammatory hyperpigmentation are observed. The remainder of the skin exam is normal, and there are no signs suggestive of an underlying endocrine disorder. What is the most likely diagnosis? A- Pityrosporum folliculitis B- Sebaceous hyperplasia C- Acne vulgaris D- Syringomas

A 17-year-old adolescent presents with a several-month history of recurrent bumps on her forehead, cheeks, and chin. The lesions initially appeared as small skin-colored or slightly red bumps but have gradually increased in number. Over the past few weeks, some have become tender, especially before her menstrual cycle. She notes mild oiliness of the skin but denies using any new skincare products, cosmetics, or hair products. She has no history of similar eruptions as a child. Her medical history is unremarkable, and she is not taking any medications. She reports no recent illness, weight changes, headaches, or signs of hormonal imbalance such as hirsutism or irregular periods. On physical examination, multiple closed and open comedones are scattered across the forehead and both cheeks. Several small erythematous papules and a few superficial pustules are also present along the jawline. There are no nodules or cystic lesions. The surrounding skin shows mild sebaceous prominence but no significant erythema outside the affected areas. Examination of the chest and upper back reveals a few scattered comedonal lesions but no deeper inflammatory nodules. Mild scarring and post-inflammatory hyperpigmentation are observed. The remainder of the skin exam is normal, and there are no signs suggestive of an underlying endocrine disorder. What is the most likely diagnosis? A- Pityrosporum folliculitis B- Sebaceous hyperplasia C- Acne vulgaris D- Syringomas

A 5-year-old boy with a recent history of varicella was brought to the doctor for persistent wrinkled spots on his skin. On dermatologic examination, numerous pink, patulous and atrophic papules of varying sizes in a round configuration were seen on the arms, trunk, and neck. Upon palpation, the lesions appeared flaccid and the examining finger “sunk” into a pit with distinct edges. The patient appeared well and had no systemic symptoms. What's the diagnosis? A- Anetoderma B- Cutis laxa C- Keloid D- Papular urticaria

A 68-year-old man presented with focal scarring alopecia and a bright red, smooth scalp nodule present for 2 months. Histology showed infiltrating neoplastic cells in collagenous stroma around hair follicles. History included colon cancer with partial colectomy 2 years ago; patient was otherwise well. What's the diagnosis? A- Alopecia neoplastica B- Lichen planopilaris C- Folliculitis decalvans D- Radiation-induced alopecia

A 57-year-old woman presents with a gradually enlarging spot on her right upper arm that she first noticed approximately 8 months ago. She reports that the lesion has become slightly more raised over time but remains asymptomatic, apart from occasional mild itching when clothing or a purse strap rubs against it.Her medical history is notable for well-controlled hypothyroidism and seasonal allergies.no personal or family history of skin cancer. On physical examination, there is a solitary, well-circumscribed, dark brown plaque on the lateral aspect of the right upper arm measuring approximately 5 mm in diameter. The lesion has a dull, uneven surface and appears to rest superficially on the skin. It has a slightly waxy texture on palpation and is loosely adherent without underlying induration.The surrounding skin is normal with no signs of inflammation, ulceration, or pigmentary changes. What is the most likely diagnosis? A- Verruca vulgaris B- Irritated melanocytic nevus C- Seborrheic keratosis D- Acrochordon

irritation in her underarms and groin. She reports that the affected areas are tender and occasionally itchy, especially after physical activity or during hot weather. She denies any discharge, fever, or use of new soaps or hygiene products. She has a history of psoriasis involving her scalp and retroauricular areas.  On physical examination, there are well-demarcated, smooth, brown plaques in the bilateral axillae and inguinal folds with a surrounding rim of erythema. The lesions appear moist with minimal surface scaling. No pustules or signs of secondary infection are noted.  A punch biopsy was performed from the left inguinal fold. Histopathology shows mild psoriasiform epidermal hyperplasia, marked spongiosis, thinning of the stratum corneum, and a superficial perivascular lymphocytic infiltrate. Munro microabscesses and significant neutrophilic infiltration are absent. What is the most likely diagnosis? A-Atopic dermatitis B- Inverse psoriasis C- Inverse pityriasis rosea D- Cellulitis

40-year-old Black man presents with a history of itchy bumps on the back of his neck that worsen after shaving his hairline for work. He notes occasional tenderness and dark spots where previous bumps have healed. Physical examination reveals multiple small, firm, dark brown papules and pustules with scattered ingrown hairs and mild post-inflammatory hyperpigmentation over the nuchal scalp. No drainage, fluctuance, or signs of infection are observed. What is the most likely diagnosis? A- Acne vulgaris B- Bacterial folliculitis C- Dissecting cellulitis D- Pseudofolliculitis barbae

A 74-year-old White man presents with a small bump on his left cheek that he first noticed about 6 months ago.The lesion has remained stable in size but has gradually become more noticeable.He denies pain, bleeding, or rapid growth.His past medical history includes hypertension and hyperlipidemia, both well controlled with medication.He has a history of chronic sun exposure because of years of outdoor work, but no prior history of skin cancer. On examination, there is a 3-mm yellowish-pink papule with a central umbilication located on the left malar cheek .The surface appears smooth and slightly lobulated, without telangiectasia, ulceration, or pearly borders.Dermoscopy reveals a central depression with a yellowish-white lobulated area surrounded by crown-like vessels that do not cross the center, consistent with sebaceous gland hyperplasia  No arborizing vessels or rolled borders What is the most likely diagnosis? A- Sebaceous adenoma B- Seborrheic dermatitis C- Basal cell carcinoma D- Sebaceous hyperplasia

A 51-year-old woman presented with well-demarcated, scaly pink plaques on the forehead, eyebrows, and glabella, developing over the past month. She was asymptomatic and reported no systemic symptoms. What's the diagnosis? A- Erythrasma B- Granuloma annulare C- Nummular dermatitis D- Sebopsoriasis (Psoriasis)

53-year-old Hispanic man presents with a persistent itchy rash on his lower abdomen that has developed gradually over the past several months.The rash began as mild redness and itching just above his belt line, but the rash has since become more inflamed and scaly.He notes that the irritation tends to worsen with sweating, particularly during his work shifts and in warm weather.He denies any recent changes in detergents, soaps, or diet.The patient states that he began wearing a new leather belt with a metal buckle about a year ago and typically wears it daily. On physical examination, there is a well-demarcated, erythematous, eczematous plaque with mild crusting and excoriations located over the midline lower abdomen, where the belt buckle contacts the skin. The surrounding area shows mild hyperpigmentation. No vesicles, pustules, or signs of secondary infection are observed. What is the diagnosis? A- Seborrheic Dermatitis B- Lichen planus C- Nickel allergic contact dermatitis D- Pityriasis rubra pilaris

A 65-year-old Black man presents with persistent itching and thickening of the skin just above his right knee, which has been ongoing for the past several months. He reports that the area has become increasingly rough and discolored, with occasional burning and sensitivity to touch. He has no history of eczema or psoriasis. He mentions that he frequently spends time gardening and often kneels on the ground for prolonged periods, usually resting on his right knee. He admits to frequently scratching the area, especially in the evenings. On physical examination, there is a single, well-demarcated, thickened, dark brown plaque with leathery texture and exaggerated skin markings over the right patella. The lesion appears hyperpigmented. No similar lesions are noted elsewhere on the body. And there are no signs of secondary infection or systemic disease. What is the most likely diagnosis? A- Acanthosis nigricans B- Atopic dermatitis C- Lichen planus D- Lichen simplex chronicus