Primary intratesticular spindle cell tumors: interdigitating dendritic cell tumor and inflammatory myofibroblastic tumor.

Spindle cell neoplasms arising in the testis are uncommon; most cases belong to the category of gonadal stromal tumors, and the presence of distinctive clinical and pathological features usually lead to a definitive diagnosis. In some instances, however, the diagnosis of these tumors can be challenging and special techniques are needed. The present study reports 2 unusual cases of primary intratesticular tumors showing a striking morphology, characterized by spindle to stellate cells in a lymphoid background. The diagnosis of interdigitating dendritic cell tumor and inflammatory myofibroblastic tumor was established in the 2 cases, and their probable origin in cells of the accessory immune system is discussed. Although both tumors share similar histological features, their immunohistochemical profiles were decisive for a definitive diagnosis.