Rare Floret Like Tyrosine Crystals in Pleomorphic Adenomas of Parotid Gland

Abstract

The pleomorphic adenoma arising in the parotid gland is a benign neoplasm that is aptly named because of its histomorphological diversity. The stromal component can contain chondromyxoid material, amyloid, and elastic fibers, along with a few rare reports of crystalline structures present in this tumor. Especially, the crystalline components are rarely encountered or appreciated in routine pathology reporting. Here, we report a case of pleomorphic adenoma of the parotid gland, in which tyrosine-rich crystalloids were identified in abundance and were confirmed with special stains and electron microscopy. Though their exact source is not yet known, crystallization of the stromal or myoepithelial cell secretion has been hypothesized. This comprehensive report is to make the histopathologists aware of this rare morphological observation in pleomorphic adenomas so that more cases are identified and followed-up to reveal the impact of their presence in a subset of pleomorphic adenomas.