Malignant Sertoli cell tumor of the testis masquerading as seminoma with bone metastasis

Sex cord-stromal tumors of the testes are rare malignancies as compared to germ cell tumors. Pure Sertoli cell tumors are still rare representing <1% of testicular cancers and the malignant forms are too rare. Furthermore, the occurrence of metastasis in such cases is extremely rare with <30 cases reported in literature so far to the best of our knowledge. We present herein a case of malignant Sertoli cell tumor in a 48-year-old male who was initially misdiagnosed as seminoma based on histology and clinical presentation. Four months later, he presented with symptoms due to bony metastasis and found to have widespread metastatic disease which is a very rare presentation of Sertoli cell tumors. Diagnosis of sex cord-stromal tumor requires high index of suspicion as these tumors are most of the times misdiagnosed as germ cell tumors due to their rare incidence and atypical presentation leading to mismanagement. Timely diagnosis at an early stage can provide therapeutic benefit due to lack of well-defined treatment options at advanced stages.