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Bivalve mollusks have been widely recognized as an important source of foodborne virus. The aim of this work was to determine the presence of norovirus (NoV) and rotavirus (RVA) in Pacific cupped oyster (Crassostrea gigas) from Buenos Aires, Argentina. A total of 88 oyster were processed. 7% of pooled samples resulted positive for NoV GII by RT-qPCR. The nucleotide analysis showed that it was closely related to GII.4/Sydney. Regarding RVA, 21% were positive by RT-qPCR targeting the NSP3 gene. RVA from one pool was isolated in cell culture and infective viral particles were evidenced by immunofluorescence. The genotype constellation of RVA/Oyster-wt/Crassostrea gigas_BA/2015/G8P[1] isolated strain was G8-P[1]-I2-R2-C2-M2-A3-N2-T6-E2-H3, which has a bovine-like genome backbone. Notably, RVA possesses an E2 genotype which is different from the characteristic E12 genotype of RVA circulating in animal species from South America. Our findings evidence not only the presence of enteric viruses in oysters from Argentina, but most important the viability of RVA. This result pose the need to implement surveillance programs to prevent potential foodborne viral outbreaks due to the consumption of contaminated shellfish.

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We report two cases of Paneth cell-like metaplasia of the prostate gland, one in poorly differentiated carcinoma and the second in benign hyperplasia. By light microscopy, the Paneth-like cells were indistinguishable from Paneth cells found in the normal small intestine and ultrastructurally showed electron-dense granules typical of Paneth cells. Immunohistochemical stains were positive for prostate-specific antigen and prostatic acid phosphatase and negative for lysozyme and alpha 1-antitrypsin. The clinical significance of Paneth cell-like metaplasia is unknown and may represent an example of the multipotential metaplastic capability of actively dividing cells.

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A tumor initially presenting as a round cell sarcoma in the proximal tibia of a 42-yr-old male disseminated to involve the femur, multiple tarsal bones, and the lungs. In addition to round cell areas resembling lymphoma, other areas of the tumor produced osteoid matrix and still other areas suggested epithelial differentiation. Immunohistochemical staining revealed the presence of epithelial markers in areas of epithelial differentiation, leukocyte markers in areas of lymphomatous differentiation, and neither marker in areas of osteosarcomatous differentiation. The finding of epithelial elements in a primary bone tumor is rare, and this report is one of the first confirming their presence using immunohistochemical markers. The findings are consonant for neither epithelial nor lymphoid neoplasms and in all probability represent multipotential differentiation in a primitive mesenchymal tumor.

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The histogenesis of alveolar soft part sarcoma (ASPS) is a subject of continued debate. Although many recent reports suggest a muscle origin, others advocate a neuroendocrine derivation. A tumor in the chest wall of a 16-year-old woman was diagnosed and treated as ASPS. The light microscopic, electron microscopic, and immunohistochemical findings showed features of both ASPS and paraganglioma. In addition, this lesion was positive for antibody to glucagon, a characteristic of neither ASPS nor paraganglioma, although seen in a few gangliocytic paragangliomas. This case demonstrates the need for continued inquiry into the histogenesis of ASPS.

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We have presented a case of luteoma of pregnancy, an uncommon ovarian lesion that is usually detected incidentally during cesarean section or postpartum tubal ligation. It is felt to be nonneoplastic, is hormonally stimulated, and regresses after childbirth. It is important to distinguish it from neoplastic lesions of the ovary that can occur in the same population, particularly steroid cell tumors, although this can be a difficult differential diagnosis.

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Echinococcosis, although relatively rare in North America, is becoming more prevalent. The rapid diagnosis of hydatid disease, using a noninvasive approach, is highly desirable. This paper describes a rare case of simultaneous pulmonary and renal echinococcosis, without demonstrable liver involvement, diagnosed by cytologic examination of a bronchial aspirate and sputum. This case emphasizes the importance of cytologic evaluation of a variety of body fluids to diagnose multiorgan infection by Echinococcus granulosus.

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Diffuse papillary proliferation of mesothelial cells in the pleura mimicking metastatic carcinoma was seen four weeks following radiation therapy for a Pancoast tumor. Such papillary proliferations are not observed incidentally and are envisioned to occur during asbestos-induced carcinogenesis. We postulate that similar papillary lesions may serve as a link in the pathogenesis of radiation-induced mesotheliomas.

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Histologic, histochemical, immunocytochemical, and ultrastructural features of two cardiac myxomas containing glandular elements are reported. Glandular elements in both cases stained positively with both mucicarmine and periodic acid-Schiff reagent with diastase pretreatment (DPAS). Immunoperoxidase studies demonstrated positivity of the glandular cells for carcinoembryonic antigen (CEA), epithelial membrane antigen (EMA), and keratin. Factor VIII-related antigen (FVIIIAg) was identified only in cells lining vascular spaces. Electron microscopic study of one tumor demonstrated well-formed glands having basement membranes, junctional complexes, and apical secretory granules. These findings indicate the capacity for true epithelial differentiation of cardiac myxomas and have implications both as regards the histologic diagnosis of these tumors and their histogenesis.

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