Ovarian microcystic stromal tumor: report of a new entity with immunohistochemical and ultrastructural studies.

Microcystic stromal tumor is a recently described rare subtype of ovarian tumor for which there has been no previously reported ultrastructural study. We report a case with the characteristic histological and immunohistochemical features and the first ultrastructural study. The immunohistochemical findings of strong and diffuse nuclear staining for beta catenin and P27 are suggestive of dysregulation of more than one genetic pathway. The ultrastructural findings are supportive of the previous postulation of an ovarian stromal origin of the neoplastic cells.

[Cellular fibroma of the ovary: description of a case]. / Fibroma cellulato dell'ovaio: descrizione di un caso.

Cellular fibromas of the ovary are rare neoplasms belonging to the group of sex-cord stromal tumours. They have been described to show from 1 to 3 mitotic figures per 10 high power fields (HPF) and they generally behave in a benign fashion. Herein we describe the clinicopathological features of a case of ovarian cellular fibroma. The patient, a 22-year-old woman, presented with acute abdominal pain. Laparotomy revealed a large ovarian mass. Histologically the lesion was composed of spindle cells showing slight or moderate pleomorphism and 3 mitoses per 10 HPF. The spindle cells were immunoreactive for vimentin, smooth muscle actin and inhibin alpha-subunit. The differential diagnoses that we considered included the mitotically active leiomyoma because of the strong positivity for smooth muscle actin, but positive immunoreaction with anti alpha-inhibin antibody helped in confirming a sex-cord stromal tumour. Electron microscopy did not show any evidence of smooth muscle differentiation.

Sclerosing stromal tumor of the ovary: a clinicopathologic, immunohistochemical, ultrastructural, and cytogenetic analysis with special reference to its vasculature.

Sclerosing stromal tumor (SST) is a rare ovarian neoplasm occurring predominantly in young women and is histologically characterized by cellular heterogeneity, prominent vasculature, and a pseudolobular appearance composed of cellular and hypocellular areas. In the current study, three cases of SST were ultrastructurally examined and the tumors were found to be composed of several kinds of cells, i.e., luteinized thecalike cells, spindle-shaped fibroblastic cells, and primitive mesenchymal cells. These findings thus supported the ovarian stromal origin of SST. Twelve cases of SST also were analyzed immunohistochemically and demonstrated an expression of vascular permeability factor/vascular endothelial growth factor (VPF/VEGF) in the luteinized thecalike cells and its receptor, fms-like tyrosine kinase 1 (flt-1), in capillary to medium-sized blood vessels. Reverse transcription-polymerase chain reaction (RT-PCR) also showed an expression of VPF/VEGF messenger RNA in SSTs. Accordingly, the characteristic vasculature and edema of SSTs were considered to be associated with the expression of VPF/VEGF. In addition, a fluorescence in situ hybridization (FISH) analysis also showed cells with three copy number of chromosome 12 in 13-21% of all examined SST cells, which suggested the presence of chromosome 12 trisomy in SSTs as well as in other ovarian stromal tumors.

Immunohistochemistry of unclassified sex cord-stromal tumors of the testis with a predominance of spindle cells.

Unclassified sex cord-stromal tumors (SCSTs) of the testis comprised predominantly of spindle cells can be difficult to classify. To achieve better definition of these tumors, we examined the histologic, histochemical, and ultrastructural features of four unclassified SCSTs with spindle-cell features, and compared their immunohistochemical features with those of 24 other SCSTs of the testis and ovary. Three of the spindle-cell tumors were composed of relatively short spindled cells with prominent nuclear grooves and intermixed epithelioid cells. All of the three were located adjacent to the rete testis. The fourth case consisted of elongate spindle cells that were reminiscent of smooth muscle. In all of the four cases, reticulin enveloped aggregates of cells of various sizes but not individual cells. Ultrastructural analysis of two of the spindle-cell tumors revealed desmosomes, numerous thin filaments, and focal dense-bodies. Immunohistochemically, all of the four tumors were reactive for S-100 protein and smooth muscle actin. Staining for S-100 protein and smooth muscle actin was also observed in three of six granulosa cell tumors and both juvenile granulosa cell tumors. Although variable staining for S-100 protein was found in 5 of the 12 other SCSTs (4 Leydig cell, 6 Sertoli-Leydig cell, and 2 unclassifiable ovarian SCSTs), reactivity for smooth muscle actin was present in only 1 Sertoli-Leydig cell tumor. In contrast, all of the four ovarian fibromas/thecomas were reactive for smooth muscle actin but failed to stain for S-100 protein. Taken together, the histologic, histochemical, immunohistochemical, and ultrastructural features of the spindle-cell tumors are similar to those of granulosa cell tumors. Reactivity for S-100 protein and smooth muscle actin is characteristic of these tumors. These tumors should be distinguished from other unclassified SCSTs.

Fusocellular gonadal stromal tumour of the testis with epithelial and myoid differentiation.

We describe an unusual fusocellular gonadal stromal tumour with a benign behaviour in the left testis from a 16-year-old man. The neoplasm consisted of a non-encapsulated proliferation of irregularly arranged, fusiform cell bundles in fibrous connective tissue. The tumour cells contained a slightly infolded nucleus, some dilated rough endoplasmic reticulum cisternae, abundant filament bundles which connected to subplasmalemmal electron-dense bodies, pinocytotic vesicles and a discontinuous basal lamina. The intercellular spaces were narrow and the tumour cells were joined by desmosomes. These cells were immunoreactive for muscle actin, alpha-actinin and vimentin. Focal immunostaining for collagen type IV was observed around the cells. No immunoreactivity for keratins, desmin S-100 protein or XIIIa factor was found. The findings suggest that the tumour arose from the peritubular myoid cells.

Smooth muscle differentiation in normal human ovaries, ovarian stromal hyperplasia and ovarian granulosa-stromal cells tumors.

An immunohistochemical and ultrastructural investigation on the presence of "smooth muscle differentiation" in stromal ovarian tissue was carried out in 10 adult granulosa cell tumors, six juvenile granulosa cell tumors, six thecoma/fibrothecomas, six cases of stromal hyperplasia, and in 10 normal ovaries. For immunohistochemistry, formalin-fixed paraffin-embedded tissues were processed using anti-alpha smooth muscle actin (alpha-SM actin) and anti-desmin as primary monoclonal antibodies. All adult granulosa cell tumors and juvenile granulosa cell tumors showed an intense alpha-SM actin immunoreaction, but weaker for desmin. Immunostain was diffuse in six out of 10 and five out of six adult granulosa cell tumors and juvenile granulosa cell tumors, respectively. Ultrastructurally, intermediate filaments focally converging into well developed desmosomes as well as peripheral bundles of myofilaments were documented both in adult granulosa cell tumors and juvenile granulosa cell tumors. In thecoma/fibrothecomas and stromal hyperplasia, alpha-SM actin and desmin expression was minimal or absent; on electron microscopy some "myoid" features and myofibroblasts were also seen. In normal ovaries, alpha-SM actin was found intensely expressed in the theca externa, focally identified in cortex-medulla, and unstained in the theca interna layer. Immunoreaction increased during folliculogenesis, going from a thin positive alpha-SM actin layer around secondary follicles to a strong diffuse stain in mature follicles. Our immunohistochemical and ultrastructural results indicate that a "smooth muscle differentiation" is a typical component of the specialized gonadal stromal tissue. A diffuse and focally alpha-SM actin is constantly present in granulosa cell tumors and thecoma/fibrothecomas, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

[An ovarian sex cord tumor with annular tubules secreting prolactin. Reality or fortunate coincidence?]. / Tumeur ovarienne des cordons sexuels avec tubes annelés productrice de prolactine. Réalité ou coïncidence fortuite?

In a 13-year old girl, an ovarian tumor was suspected of being responsible for causing amenorrhea-galatorrhea. In the absence of any abnormality of the medial umbilical folds, hormonal assessment indicated a high level of prolactin, which was restored to normal after exeresis of the mass. This was an ovarian tumor of the sexual cords with annelated tubules (SCTAT de Scully).

Experimental Sertoli cell tumors in the mouse and their progression into a mixed germ cell-sex cord proliferation.

Males of transgenic families where the large T protein of polyoma virus is expressed in the seminiferous epithelium of the testis (Sertoli and germ cells) develop bilateral testicular tumors when they become old (15 to 18 months). The histological features of these tumors revealed a neoplastic proliferation of Sertoli cell origin. Occasional isolated germ cells arrested at premeiotic stages were seen in the tumor. They did not participate in tumoral proliferation and their malignant character could not at first be established. Tumor cells injected in athymic (nu/nu) mice generated secondary tumors. In this case, a proliferative component of non-Sertoli origin was clearly evident. Its ultrastructural characteristics and the expression of genes that are transcribed in vivo in male germ cells (c-kit, LDH-X, and Hox a-4) suggest the progression of an initial, apparently pure Sertoli cell tumor into a mixed proliferation.