Dermatofibrosarcoma protuberans misdiagnosed as neurofibroma at the initial surgery : A case report

Abstract

A 49－year－old woman presented to our department with an approximately 5－year history of a persistent subcutaneous mass on the medial aspect of her right thigh. The largest mass (35×20 mm) appeared to fuse and was excised by her previous physician 3 years before her first visit to our department. Histopathological evaluation revealed a neurofibroma. Despite positive margins, they diagnosed the tumor as a benign lesion and elected close observation without intervention. The tumor recurred, and the patient visited our department for re－evaluation. We performed surgical re－excision with a 2－mm margin. Histopathological evaluation confirmed diagnosis of dermatofibrosarcoma protuberans (DFSP). We performed wide resection with a 20－mm margin, and the defect was reconstructed using a transposition flap. DFSP is diagnostically challenging ; even if hematoxylin－eosin staining suggests a benign tumor such as neurofibroma, appropriate immunohistological analysis is important for accurate diagnosis, considering the appearance and clinical course.[Skin Cancer (Japan) 2024 ; 39 : 55－60]