The role of immunosuppression in squamous cell carcinomas arising in seborrheic keratosis.

Abstract

Seborrheic keratoses (SK) are common skin neoplasms considered to be benign. Reports of associated squamous cell carcinoma arising within seborrheic keratosis (SCC-SK) have been described. To describe the histopathologic characteristics of SCC-SK and identify predisposing factors in formation of these rare lesions. There were 162 cases of SCC-SK in a span of a decade (2003-2014). All of the histopathologic specimens and medical records were reviewed. Data from these patients were compared to a control group with seborrheic keratosis who were matched by age, sex, and location of lesion from the same time period (n = 162). SCC-SK has the classic histopathologic features of SK, such as hyperkeratosis, parakeratosis, papillomatosis, and pseudohorn cysts. The areas of squamous cell carcinoma were characterized by areas of squamous dysplasia (100%), hypogranulosis (79.6%), squamous eddies (79.6%), solar elastosis (80.9%), and brown pigmentation (59.9%). Patients with a history of immunosuppression had an increased risk for developing SCC-SK (19% vs 3%; P < .01), particularly when inhibition was transplant-associated (10% vs 0%; P < .01). This was a single center, retrospective study. SCC-SK occurs more often in elderly men with a history of immunosuppression associated with organ transplants.