Rhabdomyosarcoma in Dakar: An Update on Pronostics Factors

Abstract

Rhabdomyosarcoma (RMS) belongs to the soft tissue sarcomas that have striated muscle differentiation. It is most common in young children under 5 years of age and adolescents. The definite diagnosis of rhabdomyosarcoma is based on histology and the positivity of striated muscle markers in immunohistochemistry. Our objective was to describe the prognostic characteristics of RMS diagnosed in Dakar. MATERIAL AND METHODS: This was a retrospective and descriptive study spread over nine (09) years from 1 January 2011 to 31 December 2019. It was conducted from the histological report archives of the anatomy and pathology laboratories of Dakar. Paraffin blocks were reread and immunohistochemically studied by manual method. Antidesmin and antimyogenin antibodies were used. RESULTS: We collected 44 patients with rhabdomyosarcoma out of 228 cases of soft tissue cancers, i.e. 19.29% of all malignant soft tissue tumours. The mean age of the patients was 25.41 ± 23.95 (standard deviation) years with a median age of 16 years and extremes of 6 months and 81 years. Patients were less than or equal to 17 years of age in 61.4% of cases. A clear male predominance was observed with 29 men (65.9%) against 15 women (34.1%). Rhabdomyosarcomas were located in the limbs in 34.1% of cases, in the head and neck in 29.5% of cases and in the genitourinary tract in 25% of cases. The average tumour size was 7.45 cm ± 4.64 (standard deviation) with a minimum of 2 cm and a maximum of 17 cm. It was greater than or equal to 5 cm in 15 patients (68.2%). Embryonal rhabdomyosarcoma (ERMS) was the most frequent histological type with 34 cases (77.3%), followed by pleomorphic rhabdomyosarcoma 7 cases (15.9%) and alveolar rhabdomyosarcoma 3 cases (6.8%). The histological subtypes of ERMS consisted of conventional ERMS (91.18%); botryoid RMS (5.88%) and spindle cell RMS (2.94%). The correlation between histological type and age was statistically significant (p = 0.039). A relationship was also observed between histological type and site (p = 0.026). According to the American IRS classification, the tumour was classified as group I in 41% of cases, group II in 50% of cases and groups III and IV in 4.5% each. CONCLUSION: Rhabdomyosarcoma is a rare malignant tumour in Dakar. It is often a voluminous tumour of the limbs which affects mainly males. The embryonal type is the most frequent histological form.