A 78-year-old male was referred with regards to a mass in the left upper lip. The lesion had been present for a few weeks, and whilst it was not painful the lip appeared swollen and asymmetrical. His medical history was essentially non-contributory. There were no known allergies. He currently smoked eight cigarettes per day, with an estimated 75-pack-year history. He did not consume alcohol on a regular basis.
Extra-oral examination was unremarkable and there was no evidence of regional lymphadenopathy in head and neck. Oral aperture and excursive jaw movements appeared to be normal. Intra-oral examination demonstrated a 30 x 35 x 22mm firm, fixed submucosal mass involving the left maxillary labial mucosa. There was no ulceration, and the lesion felt quite well-defined. Remaining oral soft tissues were unremarkable.
Ultrasound of the lesion demonstrated a 23 x 16 x 20mm heterogeneously hypoechoic area within the subcutaneous tissue of the left upper labial mucosa, raising the possibility of an inflammatory process possibly due to a dental abscess or nasolabial cyst. A CT was performed to further evaluate the lesion, and demonstrated a poorly defined and heterogeneously enhancing lesion measuring 32 x 17 x 12mm. There were no periapical inflammatory lesions within the maxilla, or evidence of a nasolabial cyst to account for the lesion.
Based on the clinical and radiologic evidence, the mass was thought to be either a minor salivary gland neoplasm or lymphoproliferative neoplasm. Incisional biopsy was performed under local anaesthesia. On incision, the lesion was noted to be necrotic with suppuration present.
Histopathology was reported as a mucous plug undergoing calcification partially surrounded by an intense acute inflammatory reaction and a soft tissue abscess. There was no sign of malignancy.
Sialolithiasis is a common salivary gland disease, usually developing in the major salivary glands. The most common site is the submandibular glands (80-92%), followed by the parotid glands (16-19%), and minor salivary glands are rarely affected (2%). Sialolithiasis of the minor salivary glands most commonly occurs in the buccal mucosa and upper lip.
As in this case, sialioliths of the minor salivary glands are rarely identified on imaging such as ultrasound or computed tomography due to their small size. These are often misdiagnosed clinically due to rarity and variable presentation.
The differential diagnoses for submucosal lesions in the upper lip including salivary gland tumours, mucocoeles, non-specific sialadenitis, fibroma, foreign body, vascular malformation and malignant tumours. Surgical excision is recommended to confirm the diagnosis, and is usually curative. In this case, at two-week postoperative review, the lip swelling had completely resolved and the biopsy site had healed well.
Figure 1. Firm, fixed submucosal mass in the left upper lip.
Figure 2a. Ultrasound imaging showing a hypoechoic area (23 x 16 x 20mm), demonstrating heterogeneous internal echoes.
Figure 2b. CT scan demonstrating a poorly defined, heterogeneously enhancing mass of the left upper lip (32 x 17 x 12mm) (green arrow).
Figure 3. Haematoxylin and eosin-stained section demonstrating laminated oval-shaped calcified tissue, consistent with a sialolith within a dilated minor salivary gland duct.
Images kindly supplied by Dr Rudolf Boeddinhaus, Perth Radiological Clinic
Image kindly supplied by Dr Norman Firth, Clinipath Pathology
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