In addition to germ cell tumors and tumors of the sex cord stroma, the WHO classification of testis and paratesticular tumors also contains malignant soft tissue tumors. Among them, liposarcomas of the spermatic cord are the most common entities. Other mesenchymal tumors with smooth muscle, skeletal muscle, fibroblastic/myofibroblastic, or nerve sheath differentiation are rare. Ewing sarcoma is composed of uniform small round cells and typically characterized by translocations of the EWSR1 gene. In rare cases, Ewing sarcoma-like tumors lack an EWSR1 gene fusion. Some of these tumors harbor a specific CIC translocation. However, Ewing-like sarcoma has up to now never been described in the testis or spermatic cord. The present case describes the first EWSR1-negative, undifferentiated round cell sarcoma with CIC translocation of the spermatic cord. Potential differential diagnoses are discussed.
Keywords: CIC translocation; Ewing-like sarcoma; Spermatic cord; Testis.