Mammary analog secretory carcinoma (MASC) is a recently recognized low-grade salivary carcinoma characterized by a specific ETV6 rearrangement. We describe 14 new MASCs and examine their immunophenotypic and genetic profiles in the context of look-alikes, namely, low-and high-grade salivary duct carcinoma and acinic cell carcinoma. ETV6 rearrangement, and robust expression of mammaglobin and S100, were demonstrated in 11/11, 14/14, and 12/14 MASCs, respectively. All low-grade salivary duct carcinomas coexpressed S100/mammaglobin (6/6); none harbored ETV6 rearrangements (0/5). Given that S100/mammaglobin coexpression and absence of zymogen granules are features of both MASC and low-grade salivary duct carcinoma, these two are best distinguished histologically. The former is predominantly an extraductal neoplasm with bubbly pink cytoplasm, whereas the latter is a distinct intraductal micropapillary and cribriform process. Querying ETV6 gene status may be necessary for difficult cases. No acinic cell carcinoma expressed mammaglobin (0/13) or harbored an ETV6 rearrangement (0/7); only 1/13 acinic cell carcinomas weakly expressed S100. DOG1 expression was limited or absent among all tumor types, except acinic cell carcinoma which expressed DOG1 diffusely in a canalicular pattern. Therefore, histology and immunohistochemistry (mammaglobin, S100, DOG1) suffices in distinguishing acinic cell carcinoma from both MASC and low-grade salivary duct carcinoma. HER2 (ERBB2) amplification was detected in only 1/10 acinic cell carcinomas, but none of the MASCs or low-grade salivary duct carcinomas tested. High-grade salivary duct carcinomas frequently expressed mammaglobin (11/18) and harbored HER2 amplifications (13/15); none harbored ETV6 rearrangements (0/12). High-grade salivary duct carcinomas can easily be distinguished from these other entities by histology and HER2 amplification.

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We sought to investigate the expression of the cell death protein BNIP3 in hypoxic hepatocytes, as well as the role that HIF-1α plays in the upregulation of BNIP3 in hypoxic primary mouse hepatocytes and in the livers of mice subjected to ischemia/reperfusion. Freshly isolated mouse hepatocytes were exposed to 1% hypoxia for 1, 3, 6, 24 and 48 h, and the RNA and protein were isolated for RT-PCR and Western blot analysis. Similarly, livers from mice subjected to segmental (70%) hepatic warm ischemia for 30 min or 1 h, or to 1 h ischemia followed by 0.5–4 h reperfusion, were collected and subjected to Western blot analysis for HIF-1α protein. We showed that hypoxic stress increases the formation of the BNIP3 homodimer while decreasing the amount of the monomeric form of BNIP3 in primary mouse hepatocytes. In contrast to RAW264.7 macrophages, there is a basal expression of HIF-α protein in normoxic primary mouse hepatocytes that does not change significantly upon exposure to hypoxia. Using siRNA technology, we demonstrated that reduced HIF-1α protein levels did not block the hypoxia-induced overexpression of BNIP3. In contrast to the effect on BNIP3 expression reported previously, livers from ischemic animals demonstrated only a modest increase in HIF-1α protein as compared to resting livers from control animals; and this expression was not statistically different from sham controls. These results suggest that HIF-1α does not mediate the hypoxia-induced upregulation of BNIP3 in mouse hepatocytes in vitro, and possibly in the liver in vivo.

Thymic epidermoid cysts are an extremely rare entity. These arise from epidermal cells that migrate to the thymus. The radiologic diagnosis of this rare lesion is challenging. We describe a case of an otherwise healthy 35-year-old woman who presented with an acute onset of chest pain and shortness of breath. She was found to have an anterior mediastinal mass. The imaging findings were, however, not characteristic for any single diagnostic entity. Since the imaging was inconclusive, surgical resection was performed for definitive diagnosis. The mass was found to be a thymic epidermoid cyst. This case underlines the significance for radiologists to be aware that epidermoid cysts can occur in the thymus and should be considered in the differential diagnosis for a heterogeneous anterior mediastinal mass.

No abstract

Myoepitheliomas are rare neoplasms that are typically found in the major and minor salivary glands and represent approximately 1.5% of all salivary gland neoplasms. We present a patient with an exophytic anterior midline neck mass, which was initially believed to be a thyroid isthmus nodule that underwent fine needle aspiration (FNA) biopsy. FNA cytologic evaluation reveals numerous plump spindle cells and a myxoid background, thus raising the possibility of rare benign mixed tumor of the thyroid. However, the resected specimen consists of predominately spindle cells with a minor component of chondromyxoid matrix, and no ductal epithelial cells, favoring a diagnosis of myoepithelioma. Although this lesion clinically and radiologically appeared to arise from the thyroid gland, at the time of resection, it was found to be adjacent to the thyroid isthmus and was ultimately diagnosed as a soft tissue myoepithelioma of the midneck.

Merkel's cell carcinoma is a rare cutaneous tumor that can affect a wide variety of sites throughout the body. Commonly, it affects the skin alone and the management of limited disease can be confusing since the natural history of the disease involves distant metastasis. Traditional management has required wide local excision with negative margins of resection. We describe a case treated with local therapy alone and review the literature to suggest that complete microscopic excision may not be required if adjuvant radiotherapy is used.

Velosa, C., Shi, Q., Stevens, T. M., Chiosea, S. I., Purgina, B., Carroll, W., Rosenthal, E., Morlandt, A., Loree, T. and Brandwein-Weber, M. S. (2017), Worst pattern of invasion and occult cervical metastases for oral squamous carcinoma. Head Neck. doi:10.1002/hed.24754.