Abstract

A malignancy, regarded as spindled squamous cell carcinoma, occurred in a skin ulcer in a 71-year-old female with Buerger's disease. Ulcers had often appeared at the medial malleolus of the right lower leg since she was 25 years old. The patient was previously diagnosed with Buerger's disease by angiography. A granulomatous lesion appeared after tretinoin tocoferil ointment was used for the ulcer at 70 years of age. Because the biopsy suggested a malignant tumor, below-knee amputation was carried out. The immunohistochemistry revealed staining for vimentin but not for keratin, suggesting that tumor had originated from the mesenchyma. The definite diagnosis was difficult. However, the histopathology by hematoxylin-eosin staining partially showed tumor continuity with epidermis, keratinization and intercellular bridges. Consequently, the spindled squamous cell carcinoma was speculated to have displayed abnormal expression in the immunohistochemistry.