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“A 60-year-old man presented with a painless blackish well defined nodule in the parotid duct region of the left buccal mucosa. The nodule was ∼1.0 CB-839 concentration cm in diameter, freely movable, and present 2 months (Fig. 1). The medical history was noncontributory, and the main clinical diagnosis was of a foreign body. An excisional biopsy was performed under local anesthesia, and 3 blackened stone-like fragments associated with soft

tissue were removed from the parotid duct and submitted to histopathologic examination. Macroscopic analyses of the surgical specimens showed 1 well defined black structure inside the soft tissue and 3 stone-like black fragments (Fig. 2). Microscopic analyses of the soft tissue fragment revealed a sialolith within the dilated excretory salivary duct, which presented squamous

metaplasia (Fig. 3, A). The sialolith displayed a lamellated pattern of calcification with alternation between eosinophilic and basophilic zones disposed concentrically ( Fig. 3, B). In an attempt to elucidate the nature of the black stone-like material, scanning electron microscopy (SEM; Jeol JSM-5600LV) and energy-dispersive x-ray analysis were performed. The SEM analysis of the external surface displayed a cobblestone aspect, sparse cellular elements, and organic membranous remains on the surface. Also, the longitudinal fracture surface of the black stone-like material showed parallel arrangement of the crystalline structures ( Fig. 4, A). The energy-dispersive x-ray analysis detected large amounts of carbon (C), silicium (Si), calcium (Ca), Neratinib nmr Resminostat phosphorus (P), and sodium (Na) on the rough external surface, with a predominance of C over the other elements ( Fig. 4, B). The chemical components observed in microanalyses of the black stone-like material allowed the diagnosis of sialolith. At the time of writing, the patient had been under clinical follow-up for 12 months with no recurrences and no alteration of parotid gland function. Sialoliths often develop in the ducts of the salivary glands, accounting for 30% of salivary diseases and most commonly involving

the submandibular glands (83%-94%) and less frequently the parotid glands (4%-10%) and sublingual glands (1%-7%).1 and 2 Many theories have been proposed to explain salivary calculi formation, including calcification around foreign bodies, desquamated epithelial cells, and microorganisms. In general, sialoliths are composed of an organic and an inorganic matrix presenting calcium phosphate as the major component; show a central core and a laminar peripheral structure.3 and 4 Sialolithiasis usually appear around the age of 40 years old, though it can also have an early onset in teenagers and can also affect older patients. Sialolithiasis has a predilection for male patients, particularly in cases of parotid gland.