1/28. Pathologic, cytologic and immunohistochemical findings of an intra-abdominal desmoplastic small round cell tumor in a 15-year-old male.The intra-abdominal desmoplastic small round cell tumor is a rare neoplasm. It usually occurs in young males and diffusely involves the peritoneum and pursues an aggressive clinical course. The present patient was a 15-year-old male who experienced abdominal pain and abdominal swelling. The patient was diagnosed with an intestinal myogenic sarcoma, and surgery for tumor resection was performed in June 1999. The tumor was a 20 x 15 x 15 cm well-defined mass in the peritoneum involving the transverse colon and stomach with peritoneal disseminations and splenic metastasis. Microscopic findings were well-defined nests composed of small round cells and separated by abundant desmoplastic stroma. Cytologically, the tumor cells consisted of small, round to oval cells with a scant amount of light blue cytoplasm. Immunohistochemically, the tumor cells were positive for anti-epithelial membrane antigen, vimentin, desmin, neuron-specific enolase and WT1 protein antibodies. Similar pathologic features with other small round cell tumors may lead to differential diagnostic difficulties that require the application of ancillary diagnostic methods, such as immunohistochemistry and cytogenetic techniques.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
2/28. Iatrogenic implantation of malignant meningioma to the abdominal wall.We report a case of malignant meningioma that occurred in the abdominal operation scar of a 71-year-old woman. This tumor was a 13 x 8 cm gray-tan soft tumor, consisting of multiple nodules. Histologically, tumor cells proliferated in the subcutaneous tissue, displaying mostly a storiform pattern and a focal whorl formation with high mitotic figures. The immunohistochemical positivity for epithelial membrane antigen and negativity for CD34 enabled us to differentiate this tumor from a dermatofibroma protuberance or hemangiopericytoma. The patient had a history of operation for a recurrent orbital lesion of a malignant meningioma that initially developed in the frontal skull base. The present case probably resulted from iatrogenic transplantation of the orbital malignant meningioma to the lower abdominal wall, which had served as a donor site for adipose tissue used to pack the orbital defect.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
3/28. Occult lymph node metastasis from desmoplastic small round cell tumor diagnosed by fine needle aspiration cytology. A case report.BACKGROUND: desmoplastic small round cell tumor (DSRCT) is a rare but well-defined neoplasm generally forming in the abdominal or pelvic cavity of young males and has distinct clinical, immunohistochemical and molecular features. Cytologic features of DSRCT have been described on fine needle aspiration of primary tumors. An occult lymph node metastasis of DSRCT diagnosed through the cytologic features, a basic immunocytochemical panel and dna ploidy evaluation on cytospins obtained by fine needle aspiration is reported. CASE: Aspiration cytology was performed on an inguinal lymph node from a 20-year-old male. A Diff-Quik-stained smear showed mature lymphocytes and groups of undifferentiated, small cells with scanty cytoplasm, dense and coarse chromatin, and small nucleoli. Basic immunocytochemical stains showed negativity for leukocyte-common antigen and neuron-specific enolase and positivity for cytokeratin cocktail (Cam 5.2), vimentin and desmin, the last with characteristic paranuclear dotlike positivity. dna ploidy evaluation showed an aneuploid histogram with a low 5c exceeding rate. CONCLUSION: Cytologic and immunocytochemical features suggest the diagnosis of DSRCT on fine needle aspiration cytology samples even in cases of a metastatic, unknown primary tumor. Because of the tumor's aggressiveness, a rapid and accurate diagnosis is required.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
4/28. Intra-abdominal desmoplastic small-cell tumours with divergent differentiation. Report of two cases and review of the literature.Two intraabdominal desmoplastic small cell tumours presenting in young adult males and involving the entire peritoneum, with no evident single primary site, have been studied. The histological pattern was suggestive of a metastatic small cell epithelial neoplasm, but immunohistochemical study revealed strong reactivity for cytokeratins, vimentin and desmin indicating synchronous epithelial and myogenous differentiation. In addition epithelial membrane antigen and neuron specific enolase were also positive. Electron microscopy showed fairly undifferentiated tumour cells with striking desmosome-like junctions, containing prominent paranuclear whorls of intermediate filaments, and a typical myofibroblastic stroma around neoplastic islands. Although the histogenesis of these recently described and rare tumours still remains uncertain, it seems that they constitute a reproducible entity which requires differential diagnosis from other small cell tumours of childhood and young adulthood.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
5/28. Ki-1 large cell lymphoma with regressing lesions in a child.An 8-year-old boy was seen with a cutaneous Ki-1 anaplastic, large cell lymphoma with multiple lesions. Some of the lesions showed spontaneous regression. During more than seven years of disease no systemic involvement was observed, but recurrent, self-healing lesions did appear. Histopathologic examination of five lesions revealed a variety of findings, from an inflammatory infiltrate to a highly anaplastic pattern. The neoplastic cells expressed Ki-1 and leukocyte common antigens. Ultrastructurally, those cells showed ruffled indentations. The differential diagnosis includes microvillous malignant lymphoma. The patient has had a four-year follow-up without relapses.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
6/28. Metastatic spindle cell malignant melanoma with prominent microvilli.A metastatic spindle cell malignant melanoma with positive immunoreactivity for S-100 protein and HMB-45 antigen and the presence of premelanosomes is described in a lymph node of the neck 11 years after removal of a superficial spreading malignant melanoma from the arm. Ultrastructurally, long, slender microvilli created a pattern with great similarity to an anemone cell tumor. A more solid pattern without microvilli was also present. Despite the abundance of microvilli in the anemone part of the tumor, intracytoplasmic lumina were not observed. In addition, crystalline structures within enlarged mitochondria and intracisternal tubules were noted.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
7/28. Intra-abdominal desmoplastic small round cell tumor with elevated serum CA 125: a case report.desmoplastic small round cell tumor (DSRCT) is a rare and highly aggressive tumor usually involving the peritoneum. It occurs more commonly in young males and is characterized by distinctive clinical, histologic, and immunophenotypic features. The histogenesis of DSRCT remains unknown. Coexpression of epithelial, mesenchymal, and neural antigens in the same cell provides evidence that DSRCT may arise from a primitive pluripotent stem cell with divergent differentiation. Recently, according to cytogenetic studies, some authors have proposed that the divergent differentiation of DSRCT may be the result of the fusion of Ewing's sarcoma gene and Wilms' tumor suppressor gene. Clinically, an elevated serum CA 125 concentration is found in some patients with DSRCT. We present the case of a 29-year-old man with diffuse intra-abdominal DSRCT and elevated serum CA 125 concentration and briefly review the relevant literature.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
8/28. Fine-needle aspiration cytology of multicystic mesothelioma.This report details the cytologic findings from a case of peritoneal multicystic mesothelioma (MCM). Fine-needle aspiration of a 20 cm abdominal mass in a 31-year-old man yielded a specimen which consisted of a monomorphous population of mesothelial cells lacking cytologic atypia which were arranged in three patterns: monolayered sheets, single cells, and two-cell-thick strands of mesothelial cells with little or no intervening stroma. The background was clean, without necrotic debris or abundant inflammatory cells. The mesothelial cells were not arranged in prominent papillary formations; mitotic figures were not found. The mesothelial cells were cytokeratin positive and vimentin positive, and negative for carcinoembryonic antigen (CEA) and factor viii. The FNA findings from MCM should be distinguished from those of a variety of other abdominal lesions, including cystic lymphangioma, ovarian and primary peritoneal epithelial tumors, necrotic tumors with cystic degeneration, developmental cysts, and infectious cysts.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
9/28. Ovarian involvement by the intra-abdominal desmoplastic small round cell tumor with divergent differentiation: a report of three cases.Three girls, one 14 and two 15 years of age, with the recently described neoplasm that has been designated "intra-abdominal desmoplastic small round cell tumor with divergent differentiation," and ovarian involvement at presentation are described. In two cases the ovarian tumor was initially thought to be the primary neoplasm. In all cases there was extensive extraovarian tumor at the time of presentation. The ovarian involvement was bilateral in two cases and unilateral in the third. Microscopic examination showed prominent nodular growth within the ovaries. The tumors were characterized predominantly by nests of small cells with hyperchromatic nuclei and scant cytoplasm separated by a prominent desmoplastic stroma. A few tubules containing mucinous secretion were present in one case. On immunohistochemical staining many of the tumor cells stained positively for cytokeratin, epithelial membrane antigen, desmin, and vimentin. Staining for neuron-specific enolase was present in two cases but was conspicuous in only one of them. Leu-7 was expressed by the tumor cells in two cases, and S-100 protein by one, giving further support to the possibility of neuroectodermal differentiation within some of these neoplasms. The two cases studied by electron microscopy both showed frequent intercellular junctions, basal lamina, cytoplasmic filaments, and sparse, small dense granules of either neuroendocrine or lysosomal type. Paranuclear aggregates of filaments were found in one case and cellular processes were prominent in the other case. The differential diagnosis in these cases was extensive and included a number of small cell tumors that may involve the ovary, either primarily or secondarily, in young females. The desmoplastic small round cell tumor should be considered in such cases when the appearances on routine examination are consistent with the diagnosis, and appropriate immunohistochemical stains should be performed to confirm the diagnosis.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
10/28. Biphasic synovial sarcoma of the abdominal wall.Synovial sarcoma arising in the abdominal wall is a rare tumor. We report a case of a 38-year-old man who complained of abdominal pain. physical examination revealed a firm mobile mass, 25 cm in diameter, in the left lower abdominal wall. The tumor was first thought to be a sarcoma arising from the omentum or mesentery. During surgery, a large tumor was found attached to the inner surface of the abdominal wall and compressing the gastrointestinal tract. On microscopic examination the tumor corresponded to a biphasic synovial sarcoma immunoreactive for cytokeratins (AE1/AE3, 7 and 19), epithelial membrane antigen and carcinoembryonic antigen in the epithelial tumor cells, for E-cadherin especially in their glandular structure, vimentin, CD99, and CD56 in the spindle cell component and for bcl-2 protein. The tumor recurred at the same site, and clinical course progressed to death 3 months after the initial diagnosis.- - - - - - - - - - ranking = 2keywords = antigen (Clic here for more details about this article) |
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