Basosquamous Carcinoma

Background. Basosquamous carcinoma (BSC) is a rare cutaneous tumor that has been poorly described in the dermatologic literature. It has been depicted as an aggressive tumor with a high incidence of distant metastasis. Objective. To examine the average extent of local tissue invasion and presence of distant metastases in cases of BSC compared with those of basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). Methods. One thousand consecutive Mohs surgery cases performed between January 1993 and May 1995 at the Oschner Clinic in New Orleans, Louisiana, for histologically confirmed BCC, SCC, and BSC were reviewed. Each case was retrospectively evaluated for tumor type, anatomic location, number of Mohs stages performed, and presence of metastases at the time of surgery, as determined by chest radiograph. Results. Seven hundred forty‐five BCCs, 228 SCCs, and 27 BSCs (1,000 tumors total) were treated in 580 patients. The average number of stages required for clear margins in cases of BCC, SCC, and BSC was 1.62, 1.51, and 2.00, respectively. The prevalence of metastasis was 0.87% for SCC and 7.4% for BSC, which was statistically significant (P