Primary extracranial rhabdoid tumors. Clinicopathologic features and response to ifosfamide

Malignant rhabdoid tumor (MRT) is an aggressive, invariably lethal tumor that is resistant to multimodal therapy.

The authors reviewed the clinicopathologic features, treatment, and outcome of 13 children (7 boys and 6 girls) with diagnoses of primary extracranial MRT at St. Jude Children's Research Hospital between 1981 and 1990.

The median age at diagnosis was 8 months (range, 10 weeks-18 years). Primary sites included the kidney (seven patients), liver (three patients), soft tissue of scapula, posterior mediastinum, and retroperitoneum. Seven patients had metastatic disease (lungs, six patients; cutaneous hemangioma, one patient). Ten patients had surgical resection of primary tumor (complete, nine patients; incomplete, one patient). Eleven patients had chemotherapy with multiple agents. Three of four chemotherapy responses observed were with regimens containing ifosfamide. Partial responses (PR, > 50% reduction in tumor size) were obtained in one patient who received single-agent ifosfamide during disease relapse (PR lasting 2 months), one patient who received a combination of ifosfamide, carboplatin, and etoposide at diagnosis (PR lasting 5 months), and one patient who was treated with bleomycin, cyclophosphamide, doxorubicin, and vincristine at diagnosis (PR lasting 5 months) and subsequently with ifosfamide in combination with carboplatin and etoposide during disease relapse (PR lasting 4 months). All patients died at a median period of 5 months (range, 0.5-30 months) after diagnosis.

Based on this review, the authors recommend using ifosfamide alone or in combination with carboplatin and etoposide in front-line therapy for malignant rhabdoid tumor.