SMARCB1/INI1-Deficient Extrarenal Rhabdoid Tumor: A Case Report of a Rare and Aggressive Soft Tissue Sarcoma

Malignant SMARCB1/INI1-deficient extrarenal rhabdoid tumors are aggressive tumors that are extremely rare in adults. A 56-year-old male presented with the chief complaints of unilateral lower abdominal and pelvic pain. He underwent urgent surgical intervention and mass resection with tissue sampling. After pathology confirmed the diagnosis, systemic chemotherapy with vincristine, doxorubicin plus ifosfamide, and mesna was administered. Following treatment, he experienced a durable and long-lasting response to therapy for this aggressive and rare soft tissue sarcoma. To date, the patient remains in complete remission following the cessation of chemotherapy. Malignant SMARCB1/INI1-deficient extrarenal rhabdoid tumors are aggressive neoplasms that are extremely rare in adults. We report a rare case of such a tumor and review the literature for its molecular, clinical, and imaging features.