A Case of Werner's Syndrome Associated with Osteosarcoma

Abstract We described a case of Werner's syndrome associated with osteosarcoma. A 37‐year‐old Japanese man was diagnosed as having Werner's syndrome by the presence of juvenile cataracts, skin sclerosis and hyperpigmentation of the feet, high‐pitched voice, characteristic bird‐like appearance of the face with beak‐shaped nose, thinning of the entire skin and hyperkeratoses on soles, hyperlipemia, hyperuricemia, diabetes melitus, and the mutated responsible gene (WRN). He had a 3‐month history of a tumor on his left forearm. Histologically, the tumor included four histological patterns; a malignant fibrous histiocytoma‐like, a desmoid‐like, a dermatofibrosarcoma protuberans‐like, and a chondrosarcoma‐like pattern. Tumoral osteoid formation was also found in the tumor. Therefore, the tumor was diagnosed as osteosarcoma.