Intravascular Papillary Endothelial Hyperplasia With a Phlebolith of the Tongue: A Potential Pitfall

Intravascular papillary endothelial hyperplasia (IPEH) or so-called Masson hemangioma is a benign nonneoplastic thrombus-associated organizing proliferation. De novo or secondary IPEHs are not uncommon oral lesions. An associated oral phlebolith is uncommon. Oral IPEHs and phleboliths can be diagnostically challenging. Certain histomorphologic features are helpful clues. Immunohistochemistry is a useful confirmatory tool. We present a case of an IPEH with phlebolith in a 37-year-old healthy lady who presented with a nodular lesion of the tongue. Histology showed a calcific nodule associated with an endothelial-lined vascular lesion with histomorphologic and immunohistochemical features of IPEH. The presence of a solitary extruded phlebolith could be challenging for pathologists and could be confused with other oral calculi, particularly sialoliths. The presence of papillary fronds, endothelial-lined minute vascular channels, fibrin thrombi, and hemosiderin pigment on the surface of the calculus points to a calcified thrombus. The lamellated concentric onion ring layers corresponding to Zahn lines around a central calcific nidus is another hint. Phleboliths should be considered by pathologists in their differential diagnosis of oral calculi. Distinction from sialolith is clinically important because the etiology and management are different.