Uterine rhabdomyosarcoma in adults.

Rhabdomyosarcoma (RMS) is an aggressive mesenchymal tumor most commonly diagnosed in the pediatric population, and when occurring in adults, tends to develop in the deep soft tissue of the limbs. Primary uterine RMS comprises an even more restricted subset, with little known or reported when compared to most other gynecologic sarcomas. Our goal with this study was to retrospectively evaluate cases from two academic institutions and describe the main histopathologic findings of this rare gynecologic malignancy. A total of 8 cases were identified, consisting of 4 pleomorphic rhabdomyosarcomas (PRMS), 2 alveolar rhabdomyosarcomas (ARMS), and 2 embryonal rhabdomyosarcomas (ERMS). They occurred in patients ranging from 22 to 70 years old, and the most common presenting symptom was vaginal bleeding. Most patients presented with advanced stage at diagnosis, including metastatic disease to lymph nodes and to distant sites. The masses were mostly (6/8) centered in the myometrium, while two cases arose in the cervix (2/8). Histologic characteristics of the tumors were dependent on the RMS subtype, although all cases demonstrated a similar immunohistochemical profile regardless of their subclassification. RMS of the uterus has a very poor prognosis, and data regarding treatment of this rare malignancy is limited, and usually extrapolated from non-uterine sites.