PA33.1-4 | Skin — Practice Quiz

A 68-year-old farmer presents with a 2 cm ulcerated lesion on the back of his hand with raised, everted edges and extensive surrounding solar damage. Biopsy shows irregular nests of squamous cells with central concentric whorls of eosinophilic keratin. Which mutation is most characteristically associated with UV-induced progression of the precursor lesion to this carcinoma?

A pathology slide from a skin lesion shows islands of atypical basaloid cells with peripheral palisading of nuclei and prominent retraction clefts (artefactual spaces) between tumour nests and stroma. Clinically: pearly, rolled border on the inner canthus of a 65-year-old man. Which of the following features of this tumour is most accurate?

A 55-year-old woman has a chronic non-healing ulcer on her lower leg at the site of a 20-year-old burn scar. Biopsy of the ulcer edge reveals well-differentiated squamous cell carcinoma. What is the eponym for this malignant transformation, and how does its biological behaviour compare to sun-induced SCC?

A 72-year-old immunosuppressed renal transplant recipient develops a rapidly enlarging, keratinising lesion on his right cheek. Histology shows atypical squamous cells with large keratin whorls. Compared to BCC on the same site, which statement best differentiates their metastatic risk?

A 45-year-old man has a pigmented back lesion with asymmetry, irregular border, colour variegation (black, brown, red), and 8 mm diameter. Excision biopsy shows atypical melanocytes spreading radially along the dermoepidermal junction with no dermal invasion. What growth phase does this histology represent?

A 38-year-old woman has two pigmented lesions: Lesion 1 is 3 mm, uniformly brown, symmetric, regular border; Lesion 2 is 12 mm, asymmetric, notched border, variegated (tan, dark brown, pink). Which single ABCDE criterion is LEAST useful for distinguishing benign naevus from melanoma when applied in isolation?

A 50-year-old man undergoes wide excision of a thigh melanoma. The report states: Breslow thickness 2.1 mm, Clark Level IV, no ulceration, mitotic rate 1/mm², no satellite lesions. Which measurement is the PRIMARY determinant of T-stage in current AJCC guidelines?

A dermatologist biopsies a 6 mm papule on the back of a 60-year-old man. Histology shows a well-demarcated thickened epidermis with acanthosis, hyperkeratosis, and characteristic pseudo-horn cysts (keratin-filled invaginations) within the lesion. The base sits above the surrounding epidermis, giving a 'stuck-on' appearance. Which diagnosis is most consistent?

A 25-year-old woman has a firm, brown-red 8 mm papule on her lower leg at the site of a previous insect bite. It dimples inward when pinched laterally (Fitzpatrick sign). Biopsy shows a dermal proliferation of spindle fibroblasts/histiocytes with entrapment of peripheral collagen bundles and overlying epidermal hyperplasia. What is the diagnosis?

A 52-year-old man's melanoma carries a BRAF V600E mutation. Beyond guiding targeted therapy selection, which of the following best describes this mutation's role in tumour pathogenesis?

A skin biopsy shows: (1) peripheral nuclear palisading in tumour lobules, (2) artefactual retraction clefts between tumour nests and stroma, and (3) mucinous stromal deposition. Clinically: pearly translucent nodule with telangiectasia on the nose of a 65-year-old man. Which pathway drives formation of this tumour?