Soft-tissue sarcomas in childhood. A study of 262 cases including 169 cases of rhabdomyosarcoma.

Although numerous investigations of soft-tissue sarcomas of childhood have been done, there are still many unsolved problems in the diagnosis, histogenesis, and biological behaviour of such tumours. In the present study, the soft-tissue sarcomas collected at the Paediatric Tumour Registry in Kiel were investigated. There was a total of 262 cases, including 169 (64.5%) in which a definite diagnosis of rhabdomyosarcoma had been made. An analysis of the age distribution showed that rhabdomyosarcoma is more than three times as frequent as non-rhabdomyosarcomatous soft-tissue tumours in the first quinquennium. Rhabdomyosarcoma exhibited male predominance (male-to-female ratio 1.45:1), whereas non-rhabdomyosarcomatous tumours showed an approximately equal sex distribution. Among the cases of rhabdomyosarcoma, the embryonal type clearly predominated (approx. 70%); the alveolar type was less common (approx. 20%). Correlation of histology with prognosis revealed that even tumours showing tiny foci with an alveolar pattern in otherwise solid, undifferentiated rhabdomyosarcoma, must be classified as alveolar rhabdomyosarcoma. Cases of alveolar rhabdomyosarcoma showed a higher incidence of local recurrence, lymph node metastasis, distant metastatic spread, and death, than did cases of embryonal rhabdomyosarcoma. It is concluded that "cytological differentiation" does not improve the prognosis of rhabdomyosarcoma.