Cezanne C. Cariño, MD | Janette S. Tolentino, MD | Azenith May H. Rafanan, MD
Adult rhabdomyosarcomas (RMS) arising from the female genital tract are exceedingly rare with an incidence of less than 1%. Rhabdomyosarcomas, accounting for merely 2 - 5% of all adult sarcomas, are malignant embryonal tumors that exhibit undifferentiated myogenic progenitor cells. Local studies on incidence of adult uterine RMS are lacking. This is the first reported case of embryonal rhabdomyosarcoma of gynecologic origin in this institution, involving a 27-year-old female who consulted due to recurrent vaginal bleeding associated with mild hypogastric pain. Physical examination and ultrasonographic findings were consistent with either an endometrial or endocervical polyp. Polypectomy and curettage was done. Histopathologic studies revealed dense zones of tumor cells located beneath the lining epithelium consistent with a “cambium layer” with underlying ovoid to elongated structures with cytoplasmic cross - striations indicative of rhabdomyoblasts. Also noted were nests of primitive cells admixed with ovoid glands lined by columnar epithelium containing basophilic material and areas with fetal cartilage. Immunohistochemistry studies revealed diffuse positivity for desmin, and focal positivity for myo-D1 and myogenin. Clinicoradiologic, histopathologic features and immunohistochemistry profiles were consistent with embryonal rhabdomyosarcoma. Albeit rare, uterine rhabdomyosarcoma is nonetheless an important neoplasm that should be considered in the differential diagnoses for all patients complaining of vaginal bleeding or introital mass in adult patients.