Spindle cell lipoma of the wrist, occurring in a distinctly rare location: a case report with review of literature.

Spindle cell lipoma (SCL) is a rare, benign adipocytic tumor commonly arising in the upper neck, back, and shoulder regions. To the best of our knowledge, only one case of SCL of the wrist has previously been reported. We herein report a rare case of SCL arising at the wrist. A 77-year-old man presented with a 4-year history of a mass in the right wrist. Radiography showed no significant findings, and magnetic resonance imaging demonstrated the presence of a mass on the radial dorsal side of the right wrist. Needle biopsy suggested the tumor was SCL, and total excision was performed. Macroscopically, the tumor was circumscribed by fibrous membrane with a yellowish to partly white surface. Histologically, the tumor was composed of mature adipocytes and proliferation of the less atypical spindle cells in a ropey-like collagen background. Immunohistochemically, the tumor cells showed diffuse and strong expression for CD34. The final diagnosis of SCL was made on the basis of these pathological and radiological findings. The patient was successfully treated and shows no evidence of disease at 3 months after surgery.