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

An otherwise healthy 48-year-old female presented to our clinic with a 3-‎month history of pruritic scaly brown patches and plaques in the left axilla ‎The patient had been self-treating the lesions with 1% hydrocortisone cream ‎and bacitracin, with no improvement. A biopsy was performed for ‎histopathology (Figs 5 and 6).‎ ‎1.‎ What is the most likely diagnosis?‎ a.Acanthosis nigricans b.Confluent and reticulated papillomatosis c.Darier's disease d.Axillary granular parakeratosis e.Erythasma ‎2.‎ This condition most likely develops from which of the following?‎ a.Defect in the processing of profilaggrin to filaggrin b.Excessive use of topical preparations c.Local occlusion d.Irritation from increased sweating e.All of the above

A 63-year-old male presented with a crusted, nonhealing ulcer on his right lower lip measuring approximately 1 cm × 1 cm in diameter. The lesion had been present for about 6 months and had slowly increased in size during that time (Fig 2). 1.The differential diagnosis includes all the following except: a.superficial basal cell carcinoma (BCC) b.hypertrophic actinic keratosis (AK) c.keratoacanthoma (KA) d.squamous cell carcinoma (SCC) e.seborrheic keratosis A deep shave biopsy was performed that showed atypical squamous cells and a build-up of excess keratin. The papule was excised using Mohs micrographic surgery. 2.The most likely diagnosis is: a.superficial BCC b.hypertrophic AK c.KA d.SCC e.seborrheic keratosis

A 27-year-old African American woman presented with a 5-month history of erythematous, erosive lesions with fissuring under both axillae and on the chest (Fig 1). The lesions were painful, pruritic, and worsened with heat and moisture. The patient had applied topical Neosporin (Johnson & Johnson, Titusville, NJ), which did not improve her skin problem. The patient did not take any other medications. The patient had no significant past medical history, but her family history included a similar skin problem affecting her mother and maternal uncle. On physical examination, confluent erosions on an erythematous base with crusting and fissuring were noted under both axillae. The most likely diagnosis is: a.allergic contact dermatitis b.Candidal intertrigo c.Hailey–Hailey disease d.pemphigus vegetans e.inverse psoriasis

Which of the following findings is most commonly associated with Lamellar Ichthyosis as described in the text? A) Large, brown, plate-like scales with significant associated erythema B) A "self-healing" phenotype where the skin becomes normal after membrane resolution C) Large, brown, plate-like scales with little or no associated erythema D) Involvement limited exclusively to the trunk and scalp in all patients.

A patient with thick, spiny, hyperkeratotic skin lesions is shown. What is the most likely diagnosis? A. Ichthyosis vulgaris B. Ichthyosis hystrix C. Epidermolysis bullosa D. Darier disease

A 60-year-old woman presents with several persistent scaly bumps on her fingers that have failed to improve with over-the-counter topical therapies. The lesions are asymptomatic without associated pain or pruritus. She denies bleeding, drainage, or rapid growth. She also denies a personal history of skin cancer and otherwise feels well without additional skin concerns. On physical examination, there are multiple well-circumscribed hyperkeratotic papules involving several digits of the bilateral hands (Figure 1). The lesions demonstrate a rough, verrucous surface with overlying xerosis. Dermoscopy shows thrombosed vessels (Figure 2). No surrounding erythema, ulceration, or drainage is appreciated. The remainder of the skin examination is unremarkable. What is the most likely diagnosis? A- Seborrheic keratosis B- Verruca vulgaris C- Squamous cell carcinoma D- Lymphangioma circumscriptum

A 4-year-old boy presents with a 2-week history of a pruritic facial rash. His parents bring him in and report that the lesion has become increasingly bothersome because of frequent scratching. They deny recent sick contacts, changes to topical products or detergents, or prior similar lesions. They do note recent adoption of a new kitten. The patient’s medical history is notable for B-cell acute lymphoblastic leukemia. He is otherwise healthy-appearing and interactive. On physical examination, there is a solitary annular erythematous plaque with peripheral scale on the left cheek . No additional skin lesions are identified. There is no ulceration, drainage, or surrounding induration. The remainder of the skin examination is unremarkable. QUESTION What is the most likely diagnosis? A- Bartonellosis (Cat scratch disease) B- Annular psoriasis C- Erythema migrans (Lyme disease) D- Tinea faciei

A female child presents with congenital, progressively apparent linear atrophic streaks following the lines of Blaschko, associated with patchy fat herniation producing soft yellow-pink nodules. Examination reveals dermal thinning, hypo-/hyperpigmentation, sparse hair, papillomatous lesions, nail dystrophy, dental enamel defects, ocular abnormalities, and asymmetric limb malformations including syndactyly or ectrodactyly. Histopathology demonstrates a markedly thinned dermis with adipocytes extending into the superficial dermis. The condition is usually sporadic and follows an X-linked dominant pattern. What is the most likely diagnosis? A. Incontinentia pigmenti B. Focal dermal hypoplasia (Goltz syndrome) C. Linear morphea D. Epidermal nevus syndrome E. Rothmund–Thomson syndrome

35-year-old man presents with a 2-year history of an abnormal nail growth involving a single digit associated with intermittent tenderness. He reports gradual enlargement of the lesion over time. Hedenies preceding trauma, bleeding, drainage, or pigmentary change. No prior treatments have been attempted. He otherwise feels well without additional skin or nail concerns. On physical examination, there is a localized dystrophic nail plate abnormality involving a single digit with associated longitudinal erythronychia and subungual hyperkeratotic growth (Figures 1 and 2). Mild tenderness is elicited with palpation. No surrounding erythema, drainage, or ulceration is appreciated. The remainder of the skin and nail examination is unremarkable. What is the most likely diagnosis? A- Glomus tumor B-Onychomatricoa C-Onychopapilloa D- Subungual verruca vulgaris

Which type of ultraviolet radiation is the most potent contributor to the clinical reaction shown? A. UVA B. UVB C. UVC from natural sunlight D. Infrared radiation E. Visible light

An adult woman presents with painful, erythematous areas of skin after excessive exposure to sunlight. The affected areas are warm and tender. The clinical appearance is shown in the photographs above . What is the most likely diagnosis? A. Polymorphic light eruption B. Solar urticaria C. Sunburn D. Cutaneous lupus erythematosus E. Dermatomyositis.

A 17-month-old boy presents with a 1-year history of multiple asymptomatic yellow-orange papules and nodules on the head, face, neck, and upper back. Laboratory investigations and systemic evaluation are normal. Skin biopsy demonstrates foamy histiocytes and numerous Touton giant cells. Immunohistochemistry shows CD68 positive, S-100 negative, and Langerin negative. What is the most likely diagnosis? A. Langerhans cell histiocytosis B. Mastocytoma C. Eruptive xanthoma D. Juvenile xanthogranuloma (JXG) E. Benign cephalic histiocytosis

A 45-year-old man presents with a 1-year history of progressively dry, rough skin involving the bilateral lower extremities. He reports associated mild pruritus that worsens during colder weather and after prolonged hot showers. The rash has not significantly improved despite regular use of over-the-counter emollients and moisturizers. He denies pain, blistering, drainage, or systemic symptoms. His medical history is otherwise unremarkable, and he denies a personal or family history of psoriasis, eczema, or autoimmune disease. On examination, there are fine polygonal brown-to-gray adherent scales over the bilateral shins with background xerosis . The flexural surfaces are relatively spared. There is no erythema, fissuring, or no skin secondary infection. What is the most likely diagnosis? A- Asteatotic eczema B- Stasis dermatitis C- Ichthyosis vulgaris D- Terra firma-forme dermatosis

62-year-old man presents for evaluation of a persistent “rash” on his trunk that has been present for several months. He reports the gradual development of brown discoloration that has not improved despite regular washing with soap and water. The lesions are asymptomatic, without associated itching, pain, or bleeding. He denies any recent changes in personal hygiene products or medications and denies systemic symptoms. His medical history is unremarkable. On examination, there are yellow-brown, thin, rough plaques with a “dirty” appearance on the chest and back. The lesions are non-tender and lack surrounding erythema, scale, or signs of inflammation. No excoriations, vesicles, or purpura are noted. Gentle swabbing of the affected areas with isopropyl alcohol pads results in immediate removal of the plaques, revealing normal underlying skin. What is the most likely diagnosis? A- Confluent and reticulated papillomatosis (CARP) B- Dermatosis neglecta C- Pityriasis versicolor D- Terra firma-forme dermatosis

Add She has no history of autoimmune disease, vascular disorders, or prior similar conditions and is not taking any medications.

20-year-old woman presents with episodic color changes of her fingertips triggered by cold exposure, including holding cold beverages. She reports that the episodes begin with pallor and a numb sensation, followed by a dusky or bluish discoloration, and then bright red discoloration upon rewarming of her fingers. These episodes are intermittent and have been occurring for several years. She notes mild discomfort during attacks but denies ulceration, persistent pain, or tissue breakdown. On physical examination during an episode, there is sharply demarcated pallor of multiple fingertips . The involved digits are cool to the touch, and the findings are present in both hands. No ulceration or digital pitting is observed. There is no evidence of skin thickening, sclerodactyly, or telangiectasias. Nailfold capillary examination is unremarkable, without dilated or tortuous capillaries. What is the most likely diagnosis? A- Scleroderma B- Primary Raynaud phenomenon C- Arsenic poisoning D- Hypothenar hammer syndrome

A 54-year-old man presents for a wellness examination and discloses that he has had chronic, painful open wounds on his hands, forearms, and face. The wounds start as painful blisters that eventually drain and crust. Despite 2 months of basic wound care, he returned with severe, dramatic worsening of the crusting on his face and scalp, as well as ulceration and necrosis of the unhealed wounds on his hands and forearms .The patient is unhoused and spends a great deal of time in the sun. His medical history is pertinent for tobacco use, alcoholism, and untreated hepatitis C. Blood was drawn and sent to the lab, confirming untreated hepatitis C and the presence of serum porphyrins. What is the most likely diagnosis? A- Bullous pemphigoid B- Porphyria cutanea tarda C- Bullous impetigo D- Pemphigus vulgaris

A 24-year-old woman presents with a 1-week history of a new facial rash around the mouth. She reports a gradual onset of small red bumps accompanied by mild burning and occasional pruritus. No pain, drainage, or systemic symptoms. She is employed in a health care setting and notes frequent mask use at work. She also reports regular use of facial moisturizers, but no recent changes in skincare products. No use of topical corticosteroids, inhaled steroids, or new oral medications. Her past medical history negative .On physical examination, numerous small erythematous papules and a few pustules are distributed around the perioral region, involving the nasolabial folds and chin . The vermilion border is notably spared, creating a zone of uninvolved skin immediately adjacent to the lips. No vesicles, crusting, or signs of secondary infection are observed. The remaining face is spared. What is the most likely diagnosis? A- Contact dermatitis B- Seborrheic dermatitis C- Rosacea D- Periorificial dermatitis

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