Myxoid Renal Tumor With Myoepithelial Differentiation Mimicking a Salivary Gland Pleomorphic Adenoma: Description of a Case

Abstract

We herein report an unusual case of a low-grade myxoid renal epithelial neoplasm, with peculiar and previously unreported morphologic and immunohistochemical features. The lesion was characterized by noninfiltrative borders, myxoid stroma and elongated tubular and cordlike epithelial structures. These were lined by 2 different epithelial cell types, flat and elongated basal cells and cuboidal to spindle shaped eosinophilic luminal cells, with low-grade nuclear features and a few small nucleoli. The lesion morphologically resembled a pleomorphic adenoma of the salivary gland. The immunohistochemical profile interestingly confirmed the myoepithelial differentiation of the basal epithelial layer, as demonstrated by the coexpression of several myoepithelial markers such as p63, caldesmon, calponin, smooth muscle actin, and S-100, together with epithelial markers such as low and high-molecular weight cytokeratins. The tumor proved benign at follow-up. A definitive classification and histogenetic interpretation of this previously unreported tumor type awaits description of further cases showing similar features which, perhaps, as it may happen, went so far unnoticed.

Salivary gland‐type renal carcinoma, a subset of collecting duct carcinoma: case report and meta‐analysis of the entity

“…Mucinous renal adenocarcinomas are not associated with epithelial mucin. 8 These groups are believed by some authors to probably represent low-grade collecting duct tumours, although there is no basaloid component like that in the current case. 9 In conclusion, we report a case of salivary glandtype renal carcinoma with aggressive clinical behav-iour.…”

Pleomorphic Adenoma

“…1.4 ). Pleomorphic adenomas may also be encountered outside the aerodigestive tract, for example, in the lacrimal gland, breast, vulva and sella turcica [ 26 , 113 , 114 ] and also possibly in the kidney [ 85 ]. Pleomorphic adenoma is the most common salivary gland neoplasm in adults, irrespective of the site with the exception of the sublingual gland, and accounts for approximately 60-70 % of all salivary gland neoplasms.…”

Pleomorphic adenoma with PLAG1 fusion as an isolated kidney mass: lessons learned from a challenging case

“…Recently, Parwani et al 5 . and Pacchioni et al 6 . reported a set of renal tumours with some specific features reminiscent of PA and designated them as ‘low‐grade myxoid renal epithelial neoplasms’ or ‘myxoid renal tumour with evidence of myoepithelial differentiation’.…”