Clear-cell myoepithelial carcinoma of the salivary glands: a clinicopathologic, immunohistochemical, and ultrastructural study of two cases involving the submandibular gland with review of the literature

Pathol Res Pract. 2008;204(5):335-44. doi: 10.1016/j.prp.2007.11.006. Epub 2008 Jan 18.

Abstract

Myoepithelial carcinoma (MC) is an uncommon neoplasm of the salivary glands, and cases of the clear-cell (CC) variant are extremely rare. Two cases of MC of the CC variant arising in the left submandibular gland are described herein. Both cases, which involved elderly women, almost exclusively consisted of large glycogen-rich CCs. Both cases were immunopositive for several epithelial and myoepithelial markers, and electron microscopy (EM) demonstrated hybrid epithelial and myoid differentiation in both. Case 1 arose in a pre-existing pleomorphic adenoma ("ex mixed tumor MC"), while Case 2 was a "de novo MC". CC-MC is an aggressive tumor with frequent recurrence, lymph node, and systemic metastases. A total of 14 cases of this type of neoplasm have been reported so far in the salivary glands, two arising from the submandibular gland. To date, only four cases have been studied using EM. The cases of CC-MC presented here are the third and fourth ones, respectively, originating from the submandibular glands, and the first two cases arising from this location, in which EM investigation succeeded in demonstrating myoepithelial differentiation. CC-MC needs to be distinguished from diverse primary and secondary CC neoplasms.

Publication types

  • Case Reports
  • Review

MeSH terms

  • Aged
  • Carcinoma / chemistry
  • Carcinoma / pathology*
  • Carcinoma / surgery
  • Carcinoma / ultrastructure
  • Cell Differentiation
  • Female
  • Humans
  • Immunohistochemistry
  • Microscopy, Electron, Transmission
  • Middle Aged
  • Myoepithelioma / chemistry
  • Myoepithelioma / pathology*
  • Myoepithelioma / surgery
  • Myoepithelioma / ultrastructure
  • Neoplasm Invasiveness
  • Submandibular Gland Neoplasms / chemistry
  • Submandibular Gland Neoplasms / pathology*
  • Submandibular Gland Neoplasms / surgery
  • Submandibular Gland Neoplasms / ultrastructure
  • Treatment Outcome