Minor salivary gland sialolithiasis of the upper lip.

Sialolithiasis is a common disease of the salivary glands, but it is rarely found in the minor salivary glands., Here, we reported a case of minor salivary gland sialolithiasis of the upper lip of a 58-year-old male patient.

This 58-year-old male patient came to our dental clinic for evaluation and treatment of a small solitary nodule in the left upper lip for more than 2 months. The nodule was asymptomatic, hard, and palpable at the submucosal area of the left upper labial mucosa. It measured approximately 0.2 cm in greatest dimension. The differential diagnosis included sialolithiasis, foreign body, mucocele, and benign salivary neoplasm. After discussing with the patient and obtaining the signed informed consent, the small hard nodule and the surrounding soft tissues were totally removed under local anesthesia and sent for histopathological examination. Microscopically, it showed a round salivary calculus composed of a relatively homogenous core and concentric alternating basophilic and eosinophilic bands at the periphery (Fig. 1A, B, and C). The adjacent minor labial glands revealed slightly dilated acini and salivary ducts with mucin retention in the central lumens. There were congested small blood vessels and extravasated red blood cells in the interstitial connective tissues of minor labial glands (Fig. 1D, E, and F). Therefore, the final histopathological diagnosis was minor salivary gland sialolithiasis of the upper lip.

Figure 1

Histopathological microphotographs of our case of minor salivary gland sialolithiasis of the upper lip (A, B, and C) Low- and medium-power microphotographs showing a round salivary calculus composed of a relatively homogenous core and concentric alternating basophilic and eosinophilic bands at the periphery. (D, E, and F) Low-, medium-, and high-power microphotographs demonstrating the adjacent minor labial glands with slightly dilated acini and salivary ducts showing mucin retention in the central lumens. There were congested small blood vessels and extravasated red blood cells in the interstitial connective tissues of minor labial glands. (Hematoxylin and eosin stain; original magnification; A, 2 × ; B, 4 × ; C, 10 × ; D, 4 × ; E, 10 × ; and F, 20 × ).

Sialolithiasis is a common disease of the salivary glands. The majority of the salivary calculi occur in the major salivary glands such as the submandibular glands (80%–92%) and parotid glands (16%–19%), while minor salivary glands are rarely affected (2%)., The sialolithiasis of the minor salivary gland often occurs in the upper lip and buccal mucosa and is characterized by a small, solitary submucosal nodule, which is hard and in some cases can be movable in the surrounding tissue.,

Sialoliths usually appear as radiopaque masses when the degree of calcification is high enough. Salivary stones in the terminal portion of the Wharton's duct can be demonstrated by an occlusal radiograph and sialoliths of the minor salivary glands of the upper labial mucosa or buccal mucosa can be revealed by a periapical radiograph., The differential diagnosis of a nodule in the upper lip includes sialolithiasis, foreign body, mucocele, benign and malignant salivary neoplasms, and other soft tissue tumors or diseases. Sialolith and foreign body may be characterized as a hard nodule. Mucoceles are very common in the lower lip, but are rare in the upper lip., Benign and malignant salivary neoplasms are occasionally discovered in the upper lip. We have reported a mucoepidermoid carcinoma, a palisaded encapsulated neuroma, and Kimura disease in the upper lip.3, 4, 5

Small sialoliths in the major excretory ducts of the submandibular gland and parotid gland can be treated by milking the stones toward the duct orifice. However, larger sialoliths usually need to be removed surgically. Minor salivary gland stones are best managed by surgical removal, including the adjacent minor salivary glands.,

Declaration of competing interest

The authors have no conflicts of interest relevant to this article.