title: Papillated squamous cell carcinoma in situ arising in a seborrheic keratosis.
abstract: A 73-year-old man had developed a 27 x 60-mm seborrheic keratosis on his trunk. Some months previously, an 18 x 19-mm cauliflower-like area had developed within this seborrheic keratosis. Histologic examination showed a papillated squamous cell carcinoma in situ arising in a seborrheic keratosis. Seborrheic keratoses are the most common cutaneous neoplasms in man. Malignant changes are most unusual but should be suspected in lesions of unusual clinical appearance.
mesh_terms: D000368:Aged; D001706:Biopsy; D002278:Carcinoma in Situ / Q000473:pathology*; D002294:Carcinoma, Squamous Cell / Q000473:pathology*; D002471:Cell Transformation, Neoplastic / Q000473:pathology; D006801:Humans; D008297:Male; D012878:Skin Neoplasms / Q000473:pathology*; D014860:Warts / Q000473:pathology*