PANCE Dermatology 5 — Questions and Answers
Question 1: A 35-year-old woman presents with an 8 mm pigmented lesion on her foot showing amelanotic areas and nail involvement (melanonychia). What is the most important next diagnostic step?
- Dermoscopy and punch biopsy (Correct answer)
- Topical antifungal and follow-up
- Paring to look for black dots
- Repeat examination in 6 months
Correct answer: Dermoscopy and punch biopsy
Acral lentiginous melanoma, the most common melanoma in darker-skinned individuals, can mimic benign lesions on the foot; biopsy is mandatory for any concerning pigmented acral lesion.
Question 2: A 19-year-old male presents with multiple firm, flesh-colored, umbilicated papules in the groin and inner thighs after sexual contact. What is the causative agent?
- Human papillomavirus
- Molluscum contagiosum virus (poxvirus) (Correct answer)
- Herpes simplex virus type 2
- Treponema pallidum
Correct answer: Molluscum contagiosum virus (poxvirus)
Molluscum contagiosum is caused by a poxvirus and presents with firm, umbilicated, flesh-colored papules; genital involvement in adults is sexually transmitted.
Question 3: A 48-year-old woman presents with thick, yellow, crumbling toenails with subungual debris and onycholysis. KOH preparation confirms dermatophyte infection. What is the preferred treatment for onychomycosis?
- Topical clotrimazole cream
- Oral terbinafine for 12 weeks (Correct answer)
- Topical ciclopirox lacquer
- Nail avulsion only
Correct answer: Oral terbinafine for 12 weeks
Oral terbinafine for 12 weeks (toenails) achieves significantly higher cure rates than topical agents for onychomycosis due to subungual penetration.
Question 4: A 50-year-old man presents with multiple velvety, brown-black warty plaques on his trunk that appear 'stuck on.' They have a cerebriform surface and vary in size. What is the diagnosis?
- Actinic keratosis
- Seborrheic keratosis (Correct answer)
- Verruca vulgaris
- Pigmented basal cell carcinoma
Correct answer: Seborrheic keratosis
Seborrheic keratoses are benign, pigmented, warty growths with a 'stuck-on' appearance and horn pseudocysts on dermoscopy; they require no treatment unless symptomatic.
Question 5: A 6-year-old child presents with a single circular patch of hair loss on the scalp with broken-off hairs at the scalp surface ('black dots') and mild scaling. Wood's lamp examination is negative. What is the treatment of choice?
- Topical selenium sulfide shampoo alone
- Oral griseofulvin (Correct answer)
- Topical terbinafine cream
- Intralesional triamcinolone
Correct answer: Oral griseofulvin
Tinea capitis requires oral antifungal therapy (griseofulvin or terbinafine) because topical agents cannot penetrate the hair follicle adequately.
Question 6: A 70-year-old woman presents with a firm, painless, flesh-colored papule on her lower eyelid that has grown slowly over 2 years. The border is irregular and there is perineural invasion on biopsy. What subtype of cutaneous cancer is most aggressive?
- Nodular basal cell carcinoma
- Morpheaform (sclerosing) basal cell carcinoma (Correct answer)
- Superficial BCC
- Pigmented BCC
Correct answer: Morpheaform (sclerosing) basal cell carcinoma
Morpheaform (sclerosing) BCC has the most aggressive behavior, with subclinical extension and perineural invasion, requiring Mohs surgery for adequate margins.
Question 7: A 32-year-old woman presents with pink, annular plaques with raised borders on her arms after hiking in the Southwest US. Serology confirms Coccidioides immitis infection. What skin finding is a sign of good immune response?
- Erythema multiforme
- Erythema nodosum (Correct answer)
- Diffuse macular rash
- Petechiae
Correct answer: Erythema nodosum
Erythema nodosum (tender, red subcutaneous nodules on the shins) in coccidioidomycosis indicates a strong cell-mediated immune response and a favorable prognosis.
PANCE Dermatology 5
A 35-year-old woman presents with an 8 mm pigmented lesion on her foot showing amelanotic areas and nail involvement (melanonychia).
What is the most important next diagnostic step?