Undifferentiated Endometrial Sarcoma of the Ovary: A Case Report with Review of Recent Literature and Discussion of Lacking Specificity of CD10 Immunoreactivity

Undifferentiated endometrial sarcomas (UESs) of the ovary are very rare tumors. This paper presents a case of a 56-year-old patient with a history of hysterectomy and bilateral salpingectomy seven years ago for uterine leiomyomata. Intraoperatively, a tumor originating from the left ovary, adherent to the sigmoid colon, with infiltration of the small intestine and the vaginal apex was found. Histologically, the tumor was composed of pleomorphic round and oval to spindled cells with polymorphous vesicular nuclei with coarse chromatin and large nucleoli. Mitotic activity was brisk. There were large necrotic areas. Adjacent to the tumor tissue endometrium-like glands surrounded by fibrous stroma with macrophages corresponding to ovarian endometriosis were noted. Tumor cells showed diffuse strong immunoreactivity for vimentin and patchy strong staining for CD10; no reactivities were found for AE1/AE3, desmin, S-100, LCA, CD20, c-kit, and CD31. The patient died of her neoplastic disease four months postoperatively. CD10 is frequently expressed in different gynecopathological as well as other lesions, and, thus, nonspecific without relevance to the classification of this case. Morphological features, extensive sampling, and appropriate immunohistochemistry including markers for cytokeratins and myogenic differentiation are mandatory to arrive at the correct diagnosis. 1. Introduction Ovarian endometrioid stromal sarcomas (ESSs) are rare tumors with about 50 cases reported in the literature. They are composed of cells resembling the stromal cells of normal proliferative endometrium. These tumors are reported at any age, but most of them occur in the fifth and sixth decades. At presentation, the symptoms are nonspecific and attributable to the presence of a pelvic mass. At the time of operation, most of ovarian ESS are high stage [1–6]. Previously, ESSs in general and in the ovary were categorized in low and high grade tumors based on mitotic counts. High grade ESS of the ovary accounted for 17 of cases only in one study [4, 5]. However, the lack of specific evidence of endometrial stromal cell origin in most cases of high-grade tumors leads to the designation of undifferentiated endometrial sarcomas (UESs). These sarcomas are characterized by marked cellular pleomorphism and brisk mitotic activity and carry a very poor prognosis [7, 8]. CD10, the common acute lymphoblastic lymphoma antigen (CALLA), has been reported on as a marker for normal and neoplastic endometrial stromal cells previously [9, 10]. Recently, the diagnostic consideration of CD10