PANRE Dermatology 4 — Questions and Answers
Question 1: A 40-year-old presents with pruritic, excoriated papules on the interdigital web spaces, wrists, and genitalia. His wife has similar symptoms. Mineral oil preparation of a skin scraping reveals what finding?
- Hyphae and spores
- Mites, eggs, or feces (scybala) (Correct answer)
- Gram-positive cocci
- Multinucleated giant cells
Correct answer: Mites, eggs, or feces (scybala)
Scabies is confirmed by identifying Sarcoptes scabiei mites, eggs, or scybala (fecal pellets) on microscopy of skin scrapings from burrows.
Question 2: A 65-year-old man presents with a non-healing, indurated ulcer on his lower lip with raised, everted edges. He has a 40 pack-year smoking history and dentures. Biopsy shows invasive squamous cell carcinoma. What is the most important prognostic factor?
- Tumor diameter
- Regional lymph node involvement (Correct answer)
- Perineural invasion
- Patient age
Correct answer: Regional lymph node involvement
Regional lymph node metastasis is the single most important prognostic factor for cutaneous and lip squamous cell carcinoma, significantly worsening 5-year survival.
Question 3: Which statement about seborrheic keratoses is correct?
- They are premalignant and require excision
- They are benign and have a 'stuck-on' appearance (Correct answer)
- They arise from melanocytes
- The Leser-Trelat sign confirms malignancy in all cases
Correct answer: They are benign and have a 'stuck-on' appearance
Seborrheic keratoses are benign epidermal proliferations with a characteristic 'stuck-on' waxy appearance and horn pseudocysts; they require no treatment unless symptomatic.
Question 4: A 32-year-old woman on isotretinoin for severe acne asks about contraception. What is the required minimum contraception strategy according to iPLEDGE?
- One reliable contraceptive method plus monthly pregnancy tests
- Two forms of contraception simultaneously or abstinence (Correct answer)
- One barrier method plus serum beta-hCG monthly
- Abstinence is the only acceptable option
Correct answer: Two forms of contraception simultaneously or abstinence
iPLEDGE mandates two simultaneous forms of effective contraception (or confirmed abstinence) due to isotretinoin's severe teratogenicity (Pregnancy Category X).
Question 5: A 55-year-old presents with thick, silvery-white scales overlying well-demarcated erythematous plaques on the elbows and knees. Removing a scale produces punctate bleeding (Auspitz sign). What systemic comorbidity should be screened for?
- Inflammatory bowel disease
- Psoriatic arthritis (Correct answer)
- Celiac disease
- Primary biliary cholangitis
Correct answer: Psoriatic arthritis
Psoriatic arthritis occurs in up to 30% of patients with psoriasis and should be routinely screened for, as early detection prevents joint destruction.
Question 6: A 25-year-old male has a 2 cm pink, dome-shaped nodule on his back that was removed and found to contain a cyst wall lined by stratified squamous epithelium with a granular layer, filled with cheesy keratin. What is the correct diagnosis?
- Pilar cyst
- Epidermoid cyst (Correct answer)
- Milia
- Steatocystoma
Correct answer: Epidermoid cyst
Epidermoid cysts (formerly 'sebaceous cysts') are lined by stratified squamous epithelium with a granular layer and contain laminated keratin; pilar cysts lack the granular layer.
Question 7: A 70-year-old woman presents with large, tense bullae on the flexural surfaces. Direct immunofluorescence shows linear IgG and C3 deposits at the dermal-epidermal junction. What is the diagnosis?
- Pemphigus vulgaris
- Bullous pemphigoid (Correct answer)
- Dermatitis herpetiformis
- Linear IgA bullous dermatosis
Correct answer: Bullous pemphigoid
Bullous pemphigoid is characterized by tense bullae (subepidermal blistering) with linear IgG and C3 deposits at the BMZ on DIF, targeting BP180 and BP230 antigens.
PANRE Dermatology 4
A 40-year-old presents with pruritic, excoriated papules on the interdigital web spaces, wrists, and genitalia.
His wife has similar symptoms.
Mineral oil preparation of a skin scraping reveals what finding?