Primitive neuroectodermal tumors of the abdominal wall and vulva in children: Report of two cases and review of the literature

Ewing Sarcoma of the Female Genital Tract: Clinicopathologic Analysis of 21 Cases With an Emphasis on the Differential Diagnosis of Gynecologic Round Cell, Spindle, and Epithelioid Neoplasms

Ewing sarcoma is an uncommon neoplasm considered in the differential diagnosis of tumors with "small round cell" morphology, but its occurrence in the gynecologic tract has only been sporadically documented. Herein, we describe the largest cohort of Ewing sarcoma localized to the female genital tract to date, and emphasize their clinicopathologic resemblance to more common gynecologic neoplasms. Ewing sarcoma (n=21) was retrospectively identified from 5 institutions. The average patient age was 35 (range 6-61) years. Tumor sites included uterus (n=8), cervix (n=4), vulva (n=5), vagina (n=1), broad ligament (n=1), inguinal area (n=1), and pelvis (n=1). Nine of 18 cases in which slides were available for review demonstrated only classic round cell morphology, with the remainder showing a variable combination and prominence of variant ovoid/spindle or epithelioid appearance. Tumors showed diffuse membranous reactivity for CD99 (20/20) and were positive for NKX2.2 (8/8, diffuse) and cyclin D1 (7/7, of which 3/7 were patchy/multifocal and 4/7 were diffuse). They were negative for ER (0/6) and CD10 (0/6). Three cases were initially diagnosed as endometrial stromal sarcomas. EWSR1 rearrangement was confirmed in 20/21 by fluorescence in situ hybridization (n=15) and/or sequencing (n=8). Of the eight tumors that underwent sequencing, 6 harbored FLI1 , 1 ERG, and 1 FEV as the fusion partner. Of 11 patients with available follow-up, 5 died of disease, 1 developed lung metastases and 5 are alive with no evidence of disease. Ewing sarcoma of the gynecologic tract is a rare, aggressive entity that shares some morphologic and immunohistochemical features with other more common gynecologic neoplasms. In addition to the typical round cell appearance, variant spindled/ovoid to epithelioid morphology may also be observed and should prompt consideration of this entity with appropriate immunohistochemical and/or molecular studies.

Importance of studying primitive neuroectodermal tumors and extraosseous Ewings sarcoma of the vagina and vulva

Primitive neuroectodermal tumor (PNT) and Ewing's sarcoma are rare, round-cell tumors, characterized by the presence of the t(11; 22)(q24; q12) chromosomal translocation. A review of the literature revealed only 38 previously reported cases of vulvar PNT and Ewing's sarcoma and 15 vaginal PNT and Ewing's sarcoma. Although rare, these types of tumors should be taken into consideration when making a differential diagnosis for vulvar or vaginal tumors. The currently available data is limited, and therefore, case reports are essential for improving knowledge and management of these types of extremely rare tumors. However, further molecular and histopathological studies are essential for an improved understanding of these conditions and for an early, correct diagnosis. Although the gathered and presented data from the present review are limited, the literature demonstrates that the outcome of these types of cancer are more favorable compared with outcomes observed for carcinomas in more typical locations.

Pediatric vulvar malignancies: rare but important to know

Malignancies of the vulva in the pediatric population are exceptionally rare, which makes it difficult to gain any insight into their clinicopathologic profile. In this review, we summarize all published cases of a vulva malignancy in pediatric patients (≤21 years) reported in the English language literature for the 50-year period between 1970 and 2020. We estimate that less than 100 malignancies have been reported in total, approximately 50% of which were rhabdomyosarcomas. Invasive squamous cell carcinomas, yolk sac tumors, Ewing sarcoma/primitive neuroectodermal tumors (ES/PNET) and melanomas each represented approximately 10% of reported cases. For rhabdomyosarcoma, the alveolar and embryonal subtypes were reported with equal frequency, with both representing 70% of cases combined. The average patient age was 9.8 years. 48% and 35% were Intergroup Rhabdomyosarcoma Study clinical groupings I and III respectively. Managements were generally multimodal, and overall outcomes for the group were favorable. For invasive squamous cell carcinoma, the patients were all in their teenage years, with an average age at diagnosis of 15.2 years. A small subset of cases were associated with human papillomavirus and immunosuppression, and it is possible that immunosuppression has a role in vulvar squamous carcinogenesis in this population. One case was associated with lichen sclerosus. The patients with yolk sac tumors ranged in age from less than 1 year to 20 years (mean 12) and 67% of cases were stage I at presentation. An insufficient number of cases have been reported to define their prognosis, although some cases were notably aggressive. The few reported cases of melanoma are distinctive only because they were all associated with lichen sclerosus, suggestive of some role for the latter in their pathogenesis. The average age of patients reported with ES/PNET was 15 years (range 3.3 to 20). At least half of the reported cases were advanced stage at presentation, and patient outcomes were notably poor: 62.5% were dead of disease at follow-up. Pediatric vulvar malignancies are rare and are mostly comprised of 5 entities. Their accurate pathologic classification is necessary to facilitate optimal management.