Emperipolesis in pleural fluid mesothelial cells. A phenomenon not associated with Rosai-Dorfman disease, report of a case.

Emperipolesis is a cell-within-cell phenomenon distinct from phagocytosis more often described in Rosai-Dorfman disease, where usually lymphocytes or other bone marrow cells (plasma cells, erythroblasts or neutrophils) are entirely surrounded but not engulfed by macrophages as the host cell, but occasionally megakaryocytes and neoplastic could be. Mesothelial cell has been described in a couple of cases of lymphomas affecting serous membranes, but never described in pleuritis. In the present work, the first case of emperipolesis by mesothelial cells in a patient with self-limited pleural effusion was demonstrated by immunohistochemistry and Electron Microscopy studies.

Synovial sarcoma with ossification and calcification with SS18 immunochemical expression and rearrangement by fluorescent in situ hybridization / Sarcoma sinovial con osificación y calcificación, con expresión de SS18 por inmunohistoquímica y reordenamiento de SS18 por hibridación in situ fluroescente

Synovial sarcoma is a soft tissue tumor of uncertain origin. Generally, it is a monophasic spindle cell neoplasm that can have glandular-like structures. Ossification and presence of calcification is a rare phenomenon with only a few reported cases. We present the case of a young male with a synovial sarcoma of the right foot. Histology revealed prominent deposits of tumoral osteoid and coarse calcifications. The diagnosis was confirmed by the expression of SS18 by immunohistochemistry and the demonstration of the rearrangement of the SS18 gene by fluorescent in situ hybridization. We reviewed the literature for synovial sarcoma with prominent ossification or calcification, and to the best of our knowledge, this is the first case with expression of SS18 by immunohistochemistry. The main differential diagnoses are osteosarcoma (both primary of bone and extraosseous) and sclerosing epithelioid fibrosarcoma.(AU)

El sarcoma sinovial (SS) es un tumor de partes blandas de origen incierto. Generalmente es una neoplasia monofásica de células fusiformes que puede tener estructuras de tipo glandular. La osificación y la presencia de calcificaciones es un fenómeno raro, con pocos casos reportados. A continuación presentamos el caso de un hombre joven con un sarcoma sinovial del pie derecho que en la histología mostró depósitos de osteoide tumoral y calcificaciones gruesas. El diagnóstico fue confirmado por la expresión de SS18 por inmunohistoquímica y la demostración del reordenamiento del gen SS18 por hibridación in situ fluorescente. Revisamos la literatura referente a sarcoma sinovial con osificación o calcificación prominente, y este es el primer caso con expresión de SS18 por inmunohistoquímica. Los principales diagnósticos diferenciales son con osteosarcoma (tanto primario de hueso como extraóseo) y fibrosarcoma epitelioide esclerosante (sclerosing epithelioid fibrosarcoma [SEF]).(AU)

Synovial sarcoma with ossification and calcification with SS18 immunochemical expression and rearrangement by fluorescent in situ hybridization.

Synovial sarcoma is a soft tissue tumor of uncertain origin. Generally, it is a monophasic spindle cell neoplasm that can have glandular-like structures. Ossification and presence of calcification is a rare phenomenon with only a few reported cases. We present the case of a young male with a synovial sarcoma of the right foot. Histology revealed prominent deposits of tumoral osteoid and coarse calcifications. The diagnosis was confirmed by the expression of SS18 by immunohistochemistry and the demonstration of the rearrangement of the SS18 gene by fluorescent in situ hybridization. We reviewed the literature for synovial sarcoma with prominent ossification or calcification, and to the best of our knowledge, this is the first case with expression of SS18 by immunohistochemistry. The main differential diagnoses are osteosarcoma (both primary of bone and extraosseous) and sclerosing epithelioid fibrosarcoma.

Giant-cell ependymoma: Presentation of a case of the sacral region and literature review.

Ependymoma is a rare central nervous system neoplasm with an even rarer morphologic variant called giant-cell ependymoma (GCE). GCE has a characteristic discrepant, malignant-like morphology but indolent behavior. We present the case of a 21-year-old female with an extra-axial GCE located in the sacral region. To date, 16 cases of sacral GCE have been reported in the literature, with 4 cases in the sacral region; however, all those cases were intra-axial. We present the first case of an extra-axial sacral GCE.

Utility of CD99 Paranuclear Expression in the Differential Diagnosis of Merkel Cell Carcinoma.

BACKGROUND: Recent reviews have referred to the paranuclear dot-like staining pattern of CD99 in several neoplasms, including solid pseudopapillary tumors in the pancreas, colonic adenocarcinomas, and colonic adenomas as well as in Merkel cell carcinoma (MCC). The aim of this work was to explore the utility of CD99 paranuclear staining in the differential diagnosis of MCC. MATERIAL AND METHODS: We explore paranuclear dot-like CD99 expression in several small, round blue cell neoplasms, including neuroendocrine neoplasms, Ewing sarcomas/primitive neuroectodermal tumors (EWS/PNET), melanomas, small cell lung carcinomas (SCC), lymphoblastic lymphoma/leukemia, and rhabdomyosarcomas, in comparison with 33 cases of MCC, to determine the specificity of the paranuclear dot-like CD99 expression in MCC. RESULTS: Twenty MCC (60%) demonstrated focal expression of CD99 and of those, 14 (42.4%) showed the characteristic paranuclear dot-like expression. CD99 was also paranuclear positive in 4 of 11 (36%) SCC, in 3 of 7 (43%) EWS/PNET, in 1 of 6 (16%) lymphoblastic lymphoma/leukemia cases, in 3 of 3 (100%) rhabdomyosarcomas and all melanomas were negative for the CD99 reaction. CONCLUSION: CD99 paranuclear dot-like expression was not exclusive of the MCC compared with several neoplasms included in its differential diagnosis. This expression is not a great diagnostic aid.

Expression of hormonal receptors in osteosarcomas of the jaw bones: Clinico-pathological analysis of 21 cases

BACKGROUND: Sexual hormones have an important role in many hormone-dependant tumors like breast and prostate carcinomas, and also a relationship has been found with bone metabolism and bone tumors. Some studies have demonstrated that the expression of hormonal receptors (HR) in osteosarcomas (OS) of long bones is associd with gender, histological grade, histological type, and possibly may be connection with pathogenesis and evolution. However, to our knowledge there are no studies of HR in osteosarcomas of craniofacial bones (OS-CF).OBJECTIVES: To assess the expression of hormonal receptors in OS-CF. MATERIAL AND METHODS: Twenty one cases of OS-CF were included in this study. Clinical outcome was obtained from clinical charts. Histological sections were reviewed, and immunohistochemistry studies for estrogen, progesterone and androgen receptors were performed. RESULTS: A striking female predominance was found (2:1), with a median age of 35 years. The predominant type of OS was osteoblastic (52.4%), and histological grade was high in 86%. Follow-up was obtained in 13 cases and ranged from 6 to 118 months (median 29 months). There were 8 patients (61.5%) dead or alive with progressive disease in the last follow up. Negative expression of HR was found in 19/21 cases; one showed weak nuclear expression for estrogen receptor, and another for androgen receptor. Progesterone receptor was negative in all cases. CONCLUSIONS: OS-CF mostly affected females, most of them were of the osteoblastic type and of high grade. Hormonal expression was practically negative in osteosarcoma of craniofacial bones

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Expression of hormonal receptors in osteosarcomas of the jaw bones: clinico-pathological analysis of 21 cases.

BACKGROUND: Sexual hormones have an important role in many hormone-dependent tumors like breast and prostate carcinomas, and also a relationship has been found with bone metabolism and bone tumors. Some studies have demonstrated that the expression of hormonal receptors (HR) in osteosarcomas (OS) of long bones is associated with gender, histological grade, histological type, and a possibly may be connection with pathogenesis and evolution. However, to our knowledge there are no studies of HR in osteosarcomas of craniofacial bones (OS-CF). OBJECTIVE: To assess the expression of hormonal receptors in OS-CF. MATERIAL AND METHODS: Twenty one cases of OS-CF were included in this study. Clinical outcome was obtained from clinical charts. Histological sections were reviewed, and immunohistochemistry studies for estrogen, progesterone and androgen receptors were performed. RESULTS: A striking female predominance was found (2:1), with a median age of 35 years. The predominant type of OS was osteoblastic (52.4%), and histological grade was high in 86%. Follow-up was obtained in 13 cases and ranged from 6 to 118 months (median 29 months). There were 8 patients (61.5%) dead or alive with progressive disease in the last follow up. Negative expression of HR was found in 19/21 cases; one showed weak nuclear expression for estrogen receptor, and another for androgen receptor. Progesterone receptor was negative in all cases. CONCLUSIONS: OS-CF mostly affected females, most of them were of the osteoblastic type and of high grade. Hormonal expression was practically negative in osteosarcoma of craniofacial bones.

Thyroid gland papillary carcinomas with "micropapillary pattern," a recently recognized poor prognostic finding: clinicopathologic and survival analysis of 7 cases.

Micropapillary carcinoma is a histologic pattern, rather than an independent entity, that has an aggressive clinical behavior regardless of location. Histologically, it is characterized by papillary cell groups in clear spaces. The micropapillary pattern in the thyroid gland has not been studied until recently but under other names such as hobnail features or oncocytic and, therefore, is poorly understood, and reported cases are few. We report the clinicopathologic features of 7 cases obtained from a cohort of 496 papillary thyroid carcinomas, which corresponds to a prevalence of 1.4%. The proportion of the micropapillary component accounted for between 5% and 20% of the tumors, was slightly more prevalent in men, correlated with the presence of lymphovascular permeation, and, in the survival analysis, showed lower survival (even at a short follow-up, 8.5 years) than conventional carcinoma without this component (P = .001); this is consistent with poor overall survival in the short term (2-5 years) reported for carcinomas with micropapillary pattern of other locations. We believe that owing to this difference in survival (>95% of patients with conventional papillary carcinoma are alive at 8.5 years versus 42% of those having at least 5% of micropapillary pattern), the micropapillary pattern should be correctly identified and stated in the pathology report when comprising at least 5% of the tumor.

Multicentric epithelioid hemangioendothelioma of bone. Report of a case with radiologic-pathologic correlation.

Epithelioid hemangioendothelioma (EHE) is a rare vascular tumor of uncertain biologic behavior. Most cases come out as a single lesion of the soft tissue but also may appear in the lung, liver, and other locations. Epithelioid hemangioendothelioma of bone is an extremely rare tumor and more prevalent in the second and third decades of life; its behavior is uncertain, it most commonly is unifocal, and it affects preferentially lower extremities. In this work, we present the clinical, radiologic, and pathologic findings of a 19-year-old man with a multicentric EHE of bone that involved 3 vertebrae and developed lung metastasis.

Linfadenitis necrosante y otras alteraciones histológicas en el fiebre tifoidea / Necrosing lymphademitis and other histological disorders in thyphoid fever

Con el objeto de determinar las alteraciones del sistema fagocitario fijo (SFF) en la fiebre tifoidea, se examinaron retrospectivamente las autopsias de 17 pacientes fallecidos por esta enfermedad durante los años de 1972 a 1982. Las lesiones más constantes fueron: histicitosis con hemofagocitosis en todos los órganos del SFF, microgranulomas en hígado, y bazo, y úlceras intestinales por necrosis de las placas de Peyer. Un hllazgo frecuente en esta revisión, insuficientemente informado en la literatura, es la necrosis con patrón "geográfico" que ocurre en los ganglios linfáticos mesentéricos y en la pulpa roja el bazo