2017 Volume 31 Issue 3 Pages 272-275
A 92-year-old woman had a blackish-brown plaque on her left lower back, which was diagnosed as seborrheic keratosis by incisional biopsy 5 years ago. She presented to our hospital because the tumor had become larger and hemorrhagic. There was a reddish tumor at the center of the blackish-brown plaque, which was surrounded by a brown macule. Histopathology, the reddish tumor was diagnosed as squamous cell carcinoma. The blackish-brown plaque and brown macule exhibited the findings of clonal seborrheic keratosis and solar lentigo, respectively. Seborrheic keratosis and solar lentigo are diseases on the same spectrum. We considered this case as squamous cell carcinoma arising from seborrheic keratosis.[Skin Cancer (Japan) 2016 ; 31 : 272-275]
