Salivary gland tumors are relatively uncommon and there exists a considerable diagnostic difficulty owing to their diverse histological features in individual lesions and the presence of a number of types and variants, in addition to overlapping histological patterns similar to those observed in different tumor entities. The classification is complex, but is closely relevant to the prognostic and therapeutic aspects. Although hematoxylin-eosin staining is still the gold standard method used for the diagnosis, immunohistochemistry (IHC) can enhance the accuracy and be a helpful tool when in cases to investigate the subjects that cannot be assessed by histological examination, such as the cell nature and differentiation status, cell proliferation, and tumor protein expression. This review depicts on the practical diagnostic utility of IHC in salivary gland tumor pathology under the following issues: assessment of cell differentiation, focusing on neoplastic myoepithelial cells; discrimination of histologically mimic tumor groups; diagnosis of specific tumor types, e.g., pleomorphic adenoma, adenoid cystic carcinoma, and salivary duct carcinoma; and evaluation of malignancy and prognostic factors. IHC plays a limited, even though important, role in the diagnosis of salivary gland tumors, but is often useful to support the histological assessment. However, unfortunately few tumor type-specific markers are still currently available. For these reasons, IHC should be considered a method that can be used to assist the final diagnosis, and its results themselves do not directly indicate a definitive diagnosis.

Mammary analogue secretory carcinoma (MASC) is a recently described salivary gland neoplasm that is defined by ETV6‐NTRK3 gene fusion. There have been few case reports on the cytopathologic features of MASC to date. We examined the clinicopathological and cytological features of seven cases of MASC defined by RT‐PCR analysis of the ETV6‐NTRK3 fusion gene. The cases occurred in three men and four women aged between 39 and 68 years, with a mean of 51.6 years. In five of these seven cases, the tumor involved the parotid gland. Histologically, all cases displayed predominantly microcystic patterns, often a mixture of follicular and papillary‐cystic structures. All tumors were immunoreactive for mammaglobin, S‐100 protein, and vimentin. Available fine‐needle aspiration cytology smears were cellular and exhibited many loosely cohesive syncytial clusters or isolated cells. Many histiocytes, some of which contained hemosiderin pigments, and variously shaped mucinous material were evident in the background or within the epithelial clusters. The majority of cases showed small to medium‐sized follicular structures with secreted materials. Papillary clusters were occasionally found. Tumor cells exhibited small to medium‐sized round to oval nuclei, with a smooth contour and indistinct or small nucleoli, and vacuolated cytoplasm. No tumor cells had obvious intracytoplasmic zymogen granules. It appeared that clusters of small to medium‐sized follicular and papillary configurations consisting of bland tumor cells with vacuolated cytoplasm, but lack of intracytoplasmic zymogen granules, in a mucinous or hemosiderin‐laden histiocyte‐rich background, were a characteristic cytological feature highly suggestive of MASC. Diagn. Cytopathol. 2014;42:846–855. © 2014 Wiley Periodicals, Inc.

Laminar SS stimulated the transcription of CYP1A1 through the activation of AhR in a way that is similar to the effects of PAHs. AhR was also involved in cell cycle arrest induced by SS. Our results suggest that sustained activation of AhR exposed to blood flow plays an important role in the regulation of EC functions.

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We report a rare case of inflammatory pseudotumor/inflammatory myofibroblastic tumor (IPT/IMT) of the heart, involving the mitral valve. A 58-year-old woman presenting with dyspnea was immediately admitted to the hospital, and found to have congestive heart failure due to the invagination of a tumor-like mass of the mitral valve. This mass arose from and involved almost the entire posterior leaflet of the mitral valve and occupied almost the entire mitral valve orifice. The tumor was a yellowish-white well-circumscribed mass with a smooth surface. The excised mass was 3.0 x 2.3 x 1.8 cm, and consisted of abundant Sudan III-positive foam cells, histiocytes, lymphocytes, plasma cells, and loosely arrayed spindle cells, in vascular-rich fibrous tissue. Immunohistochemistry showed that the spindle cells were positive for vimentin and alpha-smooth muscle actin, and negative for desmin, CD34, and human muscle actin (HHF-35), suggesting they were myofibroblastic cells. The plasma cells and lymphocytes showed no monoclonality. There were few mitotic cells, and, except for the lymphocytes, few Ki-67-positive cells. The findings suggested IPT/IMT. The 39 cardiac IPT/IMT cases appearing in the English-language literature are discussed.