Fibrohistiocitoma maligno (sarcoma pleomórfico indiferenciado de alto grado) sobre tofo gotoso

Gout is a uric acid metabolism disorder that is able to produce severe joint injuries. We describe a case of a 76 year old man with a history of acute gout attacks during 30 years and tophaceous deposits in hands and feet. After a quick growth of a tophus located in his left hand dorsal 2nd and 3rd metacarpophalangical joint, radiological studies were done. An image compatible with destructive uric acid deposit illness was shown. Resection was made, finding tendons affected which made necessary 2nd finger amputation. Surgical specimen showed two differentiated areas: a yellowish and granular corresponding to the typical tophaceous deposit and other fleshy and white corresponding to a high grade malignant fusocellular proliferation. Immunohistochemical studies showed only positivity for CD68 and lysozime in tumoral cells. The diagnosis of malignant fibrous histiocytoma associated to gouty tophus was made. Residual tumor was found after reintervention, and the patient was sent to the Oncology Service for adjuvant radio and chemotherapy. Five months later, the patient was reoperated for recurrence of the tumor in the left arm, staying free of disease at these moments.