Purpose or Case Report: Ewing sarcoma is the second most common malignancy of bone with an incidence of approximately 200 cases per year in the United States in children under 20. Extraosseous Ewing sarcoma originating in the vagina is rare, with only 8 cases reported to date in the literature. These highly aggressive tumors require a more intensive treatment regimen compared to other vaginal masses like rhabdomyosarcoma. While the imaging findings are non-specific, awareness of this clinical entity can facilitate early diagnosis and appropriate treatment, which may improve prognosis.
Methods & Materials: We present two cases occurring in teenagers, one of them being the youngest case reported so far. Clinical data, imaging studies and pathology reports were reviewed. Both patients underwent chemotherapy, followed by surgery or surgery and radiation.
Results: Both our cases demonstrate a heterogeneous appearance on ultrasound and MR imaging, more conspicuous in the first case where a larger mass with extensive calcifications and areas of necrosis was present. Minimal necrosis and no definite calcifications characterized the second case, possibly due to the smaller size of the mass. Neither of these lesions demonstrated significant Doppler color flow, although a few serpentine flow voids were noted on MR in the second case. Both lesions showed restricted diffusion and heterogeneous contrast enhancement on MRI. FDG avidity of the primary lesions as well as metastatic lesions was noted.
Conclusions: Ewing sarcoma, including classical Ewing sarcoma of the bone and primitive neuroectodermal tumors arising in bone or extraosseous primary sites, is a highly aggressive childhood neoplasm. We describe the spectrum of multimodality imaging appearances of Ewing sarcoma at this unusual primary site. Since imaging is not definitive, a well structured differential diagnosis for a pediatric or adolescent patient with an aggressive pelvic (extra-ovarian) lesion should include: rhabdomyosarcoma, extraskeletal Ewing sarcoma, synovial sarcoma, malignant melanoma, and less frequently carcinoma. While biopsy is key in confirming the diagnosis, imaging remains critical in defining the extent of disease, in evaluating response to treatment and in the detection of recurrent/metastatic disease.
Awareness of vaginal Ewing tumors may facilitate prompt diagnosis and lead to a different surgical approach than the more commonly encountered vaginal rhabdomyosarcoma.