Frankly Invasive Carcinoma Ex-intraductal Carcinoma: Expanding on an Emerging and Perplexing Concept in Salivary Gland Tumor Pathology.

Intraductal carcinoma (IDC) of the salivary glands is an uncommon and enigmatic tumor, our understanding of which is rapidly evolving. Recent studies have demonstrated multiple IDC subtypes and consistent gene fusions, most frequently involving RET. Because IDC is a ductal proliferation surrounded by flattened myoepithelial cells, it was previously presumed to be analogous to breast ductal carcinoma in situ, but recent evidence has shown that the myoepithelial cells of fusion-positive IDC harbor the same genetic alterations of the ductal cells and are therefore neoplastic.

NUT Carcinoma in a Patient with Unusually Long Survival and False Negative FISH Results.

Nuclear protein in testis (NUT) carcinoma is a rare and highly aggressive epithelial malignancy defined by rearrangement of the NUTM1 gene on chromosome 15q14. Histologically, NUT carcinoma is an undifferentiated carcinoma formed by sheets and nests of primitive and monotonous "round blue cells" with foci of abrupt keratinization in a subset. NUT carcinoma runs a fulminant clinical course and is almost always quickly lethal, with a median overall survival of only 6.

Low Molecular Weight Cytokeratin Immunohistochemistry Reveals That Most Salivary Gland Warthin Tumors and Lymphadenomas Arise in Intraparotid Lymph Nodes.

The nature of the lymphoid stromal component in Warthin tumor and lymphadenoma of the parotid gland has been a controversial topic in salivary gland pathology for decades. Two theories exist: first, that these tumors arise from salivary gland inclusions within intraparotid lymph nodes; and second, that they arise within salivary gland parenchyma and induce tumor-associated lymphoid proliferation (TALP). A recent study demonstrated that low molecular weight cytokeratin is effective in distinguishing salivary gland tumors within lymph nodes from those inducing TALP via identification of extrafollicular reticulum cells, which are only found in true lymph nodes.

Pediatric Warthin-like Mucoepidermoid Carcinoma: Report of Two Cases with One Persistent/Recurrent as Conventional Mucoepidermoid Carcinoma.

Mucoepidermoid carcinoma (MEC) is the most common primary salivary gland malignancy. While salivary gland neoplasia is rare in children, MEC is much more likely to occur in the pediatric population than Warthin tumor, a common benign salivary gland neoplasm associated with smoking and older age. The recently-reported Warthin-like variant of MEC bears a striking histologic resemblance to Warthin tumor, representing a potential diagnostic pitfall.

Spindle-cell variant of ameloblastic carcinoma: a report of 3 cases and demonstration of epithelial-mesenchymal transition in tumor progression.

Ameloblastic carcinoma is a rare odontogenic neoplasm that demonstrates the histologic characteristics of ameloblastoma, accompanied by the cytologic features of malignancy. The spindle-cell variant of ameloblastic carcinoma (SCAC) is exceptionally rare, with a total of 10 cases having been reported in the literature to date. Histologically, a prominent sarcomatoid cell population appears to originate from the epithelial (ameloblastic) component.