A case of Basosquamous cell carcinoma

Abstract

A 71-year-old man with basosquamous cell carcinoma (BSCC) is reported. A lesion on his right thumb appeared 6 months ago in scar tissue due to a burn. The lesion was 5X2.5cm in size. The sur- face was ulcerated and the surrounding skin was elevated. Histologic evaluation showed that the tumor was composed of three different figures: (a) a solid BCE-like lesion which consisted of basaloid cells, (b) an intermediate type lesion which showed basaloid cells and transition to squamoid cells, (c) an SCC-like lesion which consisted of squamoid cells. While in the SCC-like lesion immunohistochemi- cal staining was positive for KL-1, the BCE-like lesion was negative for KL-1 staining. From these analyses the tumor was diagnosed as BSCC. The lesion was excised with a 1cm surgical margin, and skin grafting was performed. A 2-year follow-up revealed no recurrence. [Skin Cancer (Japan) 2006; 21 : 146-150]