An 80-year-old male presented with a history of a hard right parotid mass that had gradually increased in size, with subsequent facial paralysis.A fine-needle aspiration biopsy Bi/Tri LEDs was performed.The cytologic specimens contained a substantial number of sheet-like clusters or small groups of a mixture of plasmacytoid, oval to spindled, or large epithelioid cells having hyperchromatic pleomorphic nuclei, abundant cytoplasm with occasional inclusion body-like materials, and prominent nucleoli, in a relatively clear background.
We first interpreted it as a carcinoma, suggestive of myoepithelial differentiation.Radical parotidectomy was performed, and a gross examination of the neoplasm revealed a non-capsulated and ill-defined tumor lesion, with a grayish or yellowish cut surface, associated with fat invasion.On a microscopic examination, the tumor was predominantly composed of the solid proliferation of atypical cells including a mixture of oval to spindled, plasmacytoid, or epithelioid cells, often arranged in a trabecular and reticular growth pattern with patchy eosinophilic hyalinized stroma.
Immunohistochemistry showed that the carcinoma cells were specifically positive for p63, cytokeratins, and vimentin.Finally, electron microscopy VITAMIN C COMPLEX demonstrated that their phenotype was consistent with a myoepithelial origin containing many bundles of variably thin actin filaments.Therefore, we finally made a diagnosis of myoepithelial carcinoma, defined as the malignant counterpart of benign myoepithelioma.
We should be aware that owing to its characteristic cytological features, cytopathologists may be able to make a correct diagnosis of myoepithelial carcinoma, based on multiple and adequate samplings.