Clinicopathologic features of rhabdomyosarcoma of gynecologic origin in adults.

Rhabdomyosarcoma (RMS) is the most common soft tissue tumor found in children. Up to 20% of RMS tumors in children originate in the genital tract making this the second most common site. RMS of gynecologic origin in adults is much less common. The purpose of this study was to describe the clinical and pathologic features of RMS of the adult female genital tract. We reviewed the histologic slides of women 16 years of age and older and included them in our study if they contained the classic histologic features of RMS as described by the 2002 World Health Organization classification of tumors. Rhabdomyoblastic components present in other established malignancies were not studied. We identified 15 patients, with a median age of 48 years (range, 16 to 69). Eleven (73%) of the tumors were of embryonal histology (cervix, 8; uterus, 2; and ovary, 1). Of the remaining 4 tumors, 2 were of alveolar (vulva) and 2 of pleomorphic (uterus, 1; fallopian tube, 1) histologic subtype. The majority (79%) of these patients presented with locoregional disease and had surgery as their primary intervention (73%). The median progression-free survival (PFS) and disease-specific survival was 9 months [95% confidence interval (CI), 1-24] and 21 months (95% CI, 14-28), respectively. The 5-year disease-specific survival was only 29%. There was a significant difference in PFS between cases of embryonal compared to cases with nonembryonal histology (19 vs. 3 mo, respectively) (P=0.04). Adult RMS of gynecologic origin presents with locoregional disease and most are morphologically similar to pediatric RMS; however, adult RMS behaves more aggressively, with worse overall survival. It is unclear whether these divergent outcomes are the result of differences in clinical management or because these tumors are biologically distinct.