A case of interleukin-6-producing malignant fibrous histiocytoma originating in the heart

Primary cardiac malignant fibrous histiocytoma is extremely rare and its pa thophysiological characteristics remain largely unknown. We treated a femal e patient with persistent fever and disseminated intravascular coagulation. Since ultrasonic echocardiography revealed the presence of a cardiac tumor and her serum interleukin-6 level was elevated, we speculated she had a ca rdiac myxoma. Histological examination of the surgically resected specimen, however, revealed that the tumor was malignant fibrous histiocytoma. Altho ugh her disseminated intravascular coagulation and heart failure were trans iently improved after operation, local recurrence and systemic metastasis o ccurred and she died 7 weeks after operation. Using the autopsied specimen, we examined whether the malignant fibrous histiocytoma constitutively synt hesized interleukin-6. The interleukin-6 content in the tumor was high, con sistent with interteukin-6 production by the tumor. This was confirmed by i mmunohistochemical analysis. To our knowledge, this is the first report dem onstrating interleukin-6 production by a cardiac malignant fibrous histiocy toma.