A Case of Infantile Large Parapharyngeal Rhabdomyosarcoma Followed Up for More Than 20 Years.

Rhabdomyosarcomas in the parapharyngeal space are quite rare. We report herein on the case of a 14-month-old boy who was hospitalized with a 2-month history of stridor. On admission, right peritonsillar swelling was noted. CT demonstrated the presence of a large tumor in the right parapharyngeal space. MRI findings showed a right parapharyngeal tumor, 6-cm in diameter. Histopathologic evaluation of the tumor revealed embryonal rhabdomyosarcoma. The clinical staging of the Intergroup Rhabdomyosarcoma Study Group (IRSG) was classified as group III. According to regimen 35 of the IRSG III treatment protocol, radiochemotherapy was started, comprising combination therapy with vincristine, actinomycinD, cyclophosphamide, adriamycin, and carboplatin. The patient tolerated the therapy, but with severe pancytopenia and fever. His sedation during irradiation was difficult. After he received a total dose of 10 Gy and had undergone 9 cycles of chemotherapy, an operation for the rhabdomyosarcoma was performed, resulting in successful removal of the tumor. Doses of 20 Gy were intraoperatively administered. After surgery, residual chemotherapy and irradiation was resumed. The evaluation of the response to therapy was complete remission. After 4 years from the start of therapy, all chemotherapy was halted. At present there is no evidence of recurrence or metastasis, and the patient is a well-developed college student. His sequela following therapy consisted of facial asymmetry, dental abnormalities, and pigmentation of the neck. No adriamycin cardiomyopathy was found.