An aggressive spindle cell squamous carcinoma arising in a patient with long-standing erythroderma.

Spindle cell squamous carcinoma (SCSC) of the left hand arising in a patient with long-standing erythroderma is reported. Histopathologically, spindle shaped atypical cells were observed neighboring the cells of well differentiated squamous cell carcinoma. These two types of tumor cells, spindle cells and well differentiated cells, were present side by side and merged into each other. The erythroderma had been present for over 20 years, and both clinical and histopathological findings suggested cutaneous T cell lymphoma, but were not diagnostic for mycosis fungoides, Sézary syndrome, or adult T cell lymphoma. Flow cytometry of peripheral blood cells showed a low CD4/CD8 ratio which suggested impaired T cell function. Multiple metastases of SCSC occurred in a short period and the patient died ten months after his first visit to us. The aggressive course of this case was unusual, and may be due to immunological abnormalities associated with the long standing erythroderma with impaired T cell function.