Scanning electron microscope and x-ray diffraction analysis assisting the diagnosis of a sialolith in the parotid duct

Abstract

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 ϳ1.0 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), 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.

Hard Swelling on Inner Cheek

“…The longer length and tortuous nature of the submandibular duct with the thicker consistency of submandibular saliva likely contribute to this predilection. Although rarer in occurrence, sialoliths can also develop in ducts of minor salivary glands, the sublingual gland, and, as in this case, the parotid gland . The rarity of sialoliths in the parotid gland duct is likely due to the serous nature of parotid gland saliva.…”

“…Although rarer in occurrence, sialoliths can also develop in ducts of minor salivary glands, the sublingual gland, and, as in this case, the parotid gland. 1,2 The rarity of sialoliths in the parotid gland duct is likely due to the serous nature of parotid gland saliva. Formation of a sialolith involves the concentric deposition of calcified material around a central nidus.…”

Computational fluid dynamics analysis of salivary flow and its effect on sialolithogenesis

“…The formation of stones in the salivary extraglandular system has been predominantly attributed to slow salivary flow, salivary stagnation, and intricate metabolic events (Waseem and Forte, 2005). Various studies (Kinoshita et al , 2008; Su et al , 2010; Ribeiro et al , 2011) have demonstrated the microstructure of sialoliths and features of electrolyte alteration in saliva during pathologic states; however, less attention has been paid to the macroscopic effects of changes in salivary flow. Using CFD, we explored the changes in the salivary flow field of Stensen’s duct, which we believe may affect the symptoms and prognosis of this pathologic condition.…”