Low-grade endometrial stromal sarcoma with intracardiac extension. Evolution of extensive smooth muscle differentiation and usefulness of immunohistochemistry for its recognition and distinction from intravenous leiomyomatosis.

This case, a rare example of low-grade endometrial stroma sarcoma with extensive smooth muscle differentiation which extended to the inferior vena cava and cardiac chambers closely resembling intravenous leiomyomatosis grossly and microscopically, illustrates the importance of extensive sectioning and the usefulness of immunohistochemistry. Although spindle cell components arranged in interlacing bundles consistent with smooth muscle differentiation were recognizable in the primary tumor (on retrospective review), extensive smooth muscle differentiation in the recurrent tumors masked prototypical morphologic features of stromal sarcoma and only small neoplastic stromal components were preserved in limited areas, leading to initial failure to distinguish the lesion from intravenous leiomyomatosis. The immunophenotyping disclosed two distinct cell populations in the tumor: i.e. vimentin-positive and smooth muscle marker negative stromal cells, and vimentin-negative spindle-shaped desmin-positive smooth muscle cells. Our observation suggests that the predominance of a smooth muscle component in such a tumor can be misleading and does not always warrant a diagnosis of intravenous leiomyomatosis, nor does it predict a benign clinical course. This case also provides an insight into the relationship of the endometrial stroma and myometrium, and their cell of origin and the histogenesis of endometrial stromal sarcoma.

Ovarian small cell tumors: an electron microscopic review.

Small cell tumors of the ovary are uncommon but represent an important group to recognize in the differential diagnosis of primary and metastatic ovarian neoplasms. In some cases the correct diagnosis cannot be confidently made on the basis of clinical setting, routine light microscopy, and immunohistochemistry, and electron microscopy may be supportive or definitive in establishing cell type. The cell type is often important in choosing optimal therapy and in predicting prognosis. The authors performed electron microscopy on a moderate number of ovarian small cell tumors and here describe and illustrate the diagnostic features of representative examples of various types. The ultrastructural features of the metastatic tumors, such as embryonal rhabdomyosarcoma, neuroblastoma, and melanoma, are identical to those of their respective primary tumors, are well known, and usually pose no problem in diagnosis. On the other hand, the ultrastructural features of some primary ovarian small cell tumors may present a more difficult differential diagnosis, because they have features that are subtle and/or in common. Exemplary of tumors in this category are diffuse adult granulosa cell tumor, endometrial stromal sarcoma, and small cell carcinomas of the hypercalcemic and pulmonary (oat cell) types. Distinguishing among them may be difficult but is possible, and electron microscopy may be a valuable supplement to the diagnostic information obtained from the clinical presentation, light microscopy, immunohistochemistry and, in some tumors, cytometric analysis of these neoplasms.

Characterization of a newly established endometrial stromal sarcoma cell line.

We describe a newly established human sarcoma cell line derived from an endometrial stromal sarcoma (ESS). The cell line has been maintained in long-term cell culture for more than 2 years. It has been repeatedly analyzed in terms of morphology, immunocytochemical features, ultrastructure and karyotypic characteristics. In contrast to uniform endometrial stromal differentiation in vivo, the tumor cells were shown to display distinct phenotypical heterogeneity in vitro. In addition to the predominant cell type, which retained sarcomatous differentiation, foci of epithelial-like cells were observed in the cell culture. Immunocytochemical and ultrastructural analysis demonstrated a mainly mesenchymal phenotype with signs of epithelial characteristics, such as expression of cytokeratins, and the presence of desmosomes and kinetocilia, respectively. Cytogenetic analyses in early and late passages revealed unbalanced translocations between chromosomes 3 and 6 and an additional i(19)(q10), as common karyotypic changes in all tumor cells, indicating a monoclonal origin. Our new cell line can be used as an in vitro model to study the mechanisms of heterogeneous differentiation patterns in ESS.

Endometrial stromal sarcoma with sex cord-like areas and focal rhabdoid differentiation.

An unusual uterine lesion is described in a patient with postmenopausal bleeding. Grossly, a yellow, polypoid mass projected into the uterine cavity. Histological examination showed a distinct biphasic pattern with areas of typical low-grade endometrial stromal sarcoma and areas where tumour cells were arranged in cords and trabeculae, resulting in a sex cord-like pattern. In these areas the cells assumed a rhabdoid morphology with eccentric vesicular nuclei, prominent nucleoli and eosinophilic hyaline cytoplasmic inclusions. Immunohistochemistry showed positive cytoplasmic staining of both components for vimentin, desmin and the cytokeratin marker CAM 5.2, but no staining for CEA and EMA. Electronmicroscopy revealed prominent paranuclear arrays of intermediate filaments. This is the second reported case of endometrial stromal sarcoma with rhabdoid differentiation and the first documented example of rhabdoid cells in sex cord-like areas. The report adds to the list of diverse neoplasms which may display a characteristic rhabdoid morphology and supports the hypothesis that extrarenal rhabdoid tumours are not a distinct clinicopathological entity. A diagnosis of malignant rhabdoid tumour of the uterus should be considered only when extensive sampling fails to disclose areas with an appearance typical of an endometrial stromal lesion.

Interphase cytogenetic study of endometrial stromal sarcoma by chromosome in situ hybridization.

Endometrial stromal neoplasms include a heterogenous group of tumors with different clinical behavior and response to treatment. Cytogenetic study of such tumors has been scanty. The aim of this study was to analyze and compare the chromosome composition in low-grade and high-grade endometrial stromal sarcoma using the technique of chromosome in situ hybridization. Eight cases of low-grade stromal sarcoma and three cases of high-grade stromal sarcoma were studied. Biotinylated DNA probes specific for the regions of chromosomes X, 11, 12, and 17 were used on formalin-fixed paraffin embedded material from these tumors. The in situ hybridization signals were visualized by immunoperoxidase technique. Four of the eight low-grade stromal sarcomas retained normal disomy of the chromosomes studied. The other four low-grade sarcomas showed a gain of from one to three chromosomes, whereas all of the three high-grade sarcomas showed polysomies in all of the four chromosomes being studied. No loss of chromosomes was detected. One case of high-grade sarcoma contained coexisting areas of low-grade sarcoma. Although aneusomy was found in the high-grade portion, disomy was noted in the low-grade areas. In the stromal sarcomas studied, there was no definite correlation between the presence of chromosome polysomies and the clinical progress of the tumors. This is the first interphase cytogenetic study of uterine stromal sarcoma, and the results support the concept that complex numerical chromosome abnormalities evolve during anaplastic transformation of endometrial stromal sarcoma.

Endometrial stromal sarcoma with focal smooth muscle differentiation: recurrence after 17 years: a follow-up report with discussion of the nomenclature.

In 1977, a case report was published describing a 28-year-old women with an endometrial stromal tumor that showed foci of myogenic differentiation. The term "stromomyoma" was introduced to encompass both this type of neoplasm as well as "uterine neoplasms resembling ovarian sex-cord tumors" (UTROSCTs). More than 17 years later, the tumor recurred, involving the right ovary, sigmoid colon, small bowel, abdominal wall and omentum. The histologic and electron microscopic similarities between the recurrent tumor and the primary neoplasm were confirmed. Applying the recent classification and diagnostic criteria of endometrial mesenchymal neoplasms, we have concluded that this tumor was a low-grade endometrial stromal sarcoma (LGSS). The formerly proposed term "stromomyoma" implies a benign tumor, in contrast to the obviously malignant nature of this particular tumor. Focal myogenic differentiation of LGSS is not an uncommon finding and does not warrant a separate diagnostic or prognostic entity. UTROSCTs and endometrial stromal sarcomas are two separate diagnostic entities, and combining them under an inclusive terminology is not appropriate.

Sarcoma de tipo estroma endometrial extracorporales uterinos / Extracorporal uterine endometrial stromal-like sarcomas

Se presentan 3 sarcomas de tipo estroma esdometrial primarios extracorporales uterinos. Uno de ellos ovárico, bilateral, con extenso compromiso y permeaciones vasculares paratubarias parametriales, del epiplón y del tejido periureteral, asociado a endometriosis ovárica y del tejido paraureteral. Los otros dos casos eran lesiones polipoideas localizadas, una en el endocérvix, otra vaginal. Ninguno de estos 2 casos se asoció a endometriosis. Histológicamente los tumores estaban compuestos por células redondeadas, de escaso citoplasma, abundantes vasos pequeños y bajo índice mitótico. Estos hallazgos corresponden a los de sarcomas de tipo estroma endometrial, de bajo grado. Los presente casos enfatizan la multipotencialidad de los órganos müllerianos, no sólo por su capacidad de desarrollar diferentes tumores epiteliales paramesonéfricos, sino también diferentes sarcomas müllerianos