Signet Ring Cell Differentiation in Salivary Duct Carcinoma with Rhabdoid Features: Report of Three Cases and Literature Review

AbstractSalivary duct carcinoma with rhabdoid features (SDCRF) is a rare salivary tumor with poor prognosis and is proposed as a salivary counterpart of pleomorphic lobular carcinoma of the breast (PLCB). Here, we report three cases of SDC with rhabdoid features (SDCRF) mimicking PLCB. Pleomorphic adenoma (PA) component was accompanied in all the cases confirming carcinoma ex PA. One patient had frequent rhabdoid features and showed invasive growth into the surrounding tissue. The other two patients had intracapsular tumor but with rhabdoid features. The patients with intracapsular SDCRF survived for  >  5 years after surgery with no evidence of recurrence, whereas the patient with extracapsular SDCRF died 10 months after biopsy, and autopsy revealed disseminated metastasis to the central nervous system. Histologically, tumor cells in all three cases resembled PLCB, with a discohesive appearanc e, abundant cytoplasm, enlarged hyperchromatic nuclei, and similar immunohistochemical profiles, namely loss of membranous E-cadherin, obscured expression of membranous β-catenin, diffuse positivity of androgen receptor, gross cystic disease fluid protein-15, mitochondrial adenosine triphosphate sy nthase subunit β, MUC1, and INI-1. Estrogen and progesterone receptors were negative, and HER2 immunoreactivities were variable. The tumor cells of extracapsular invasive SDCRF exhibited higher MIB-1 labeling index and more frequent intracytoplasmic lumina than those of intracapsu...
Source: Head and Neck Pathology - Category: Pathology Source Type: research