PO:10:153 | Isolated sarcoidosis of the parotid gland: a rare case of unilateral presentation

Irene Carlino¹, Giorgio Carlino², Silvia Lombardo³, Luigi Gennari¹ | ¹Internal Medicine Unit, Department of Medicine Surgery and Neuroscience, University of Siena; ²ASL Lecce, Rheumatology Service DSS Casarano-Gallipoli-Gagliano del Capo, Gallipoli (LE); ³ASL Lecce, DSS Gagliano del Capo, Ugento (LE); Italy

Abstract

Sarcoidosis is a chronic multisystem inflammatory disease of unknown etiology, histologically characterized by non-necrotizing granulomas. Pulmonary and mediastinal lymph node involvement is most common, but the skin, eyes, liver, spleen, and salivary glands may also be affected. Salivary gland involvement is rare (<6%) and isolated unilateral presentation is even more exceptional.

We describe the case of a 52-year-old Caucasian woman, with no previous medical conditions, who presented with progressive enlargement of the right parotid gland over approximately two months. She reported no systemic or local symptoms (xerostomia, dysphagia, dyspnea, skin lesions). Physical examination revealed an oval mass of approximately 5 cm, with irregular borders, non-tender and poorly mobile, along with enlarged submandibular and cervical lymph nodes (up to 2 cm), mobile and painless (Fig. 1a). Blood tests showed elevated serum ACE levels (124 U/L; normal range 13.3–63.9), mildly elevated ESR (17 mm/h), normal calcium levels, negative Quantiferon test, and normal liver and kidney function. Ultrasound revealed solid, hypoechoic, vascularized lesions (up to 29×15 mm) in the anterior portion of the gland, compatible with pathological lymph nodes (Fig. 1b). MRI confirmed right parotid nodules up to 17 mm with irregular margins, marked diffusion restriction, and minimal central enhancement. Similar lesions were observed in the ipsilateral submandibular and supraclavicular regions (Fig. 1c and 1d). Fine-needle aspiration revealed non-necrotizing granulomas composed of CD68-positive epithelioid histiocytes, multinucleated giant cells, and lymphocytic infiltrate, with no evidence of infection or malignancy. Chest CT excluded mediastinal or pulmonary involvement. The left parotid gland was unaffected. A diagnosis of isolated sarcoidosis of the right parotid gland was therefore made. Treatment was initiated with prednisone 25 mg/day for 14 days, followed by gradual tapering. After two months, the swelling had completely resolved, with no clinical recurrence. Parotid involvement in sarcoidosis is known, typically associated with Heerfordt’s syndrome. However, isolated unilateral forms are extremely rare. In the review by Ungprasert et al. (2016), only 1 out of 345 patients presented isolated parotid sarcoidosis, and no unilateral cases in Caucasian patients were reported. Differential diagnosis with neoplastic or infectious conditions is essential to avoid inappropriate surgical intervention. Ultrasound and MRI provide useful diagnostic clues, but biopsy is necessary for confirmation. The presence of non-caseating granulomas in the absence of infectious agents is the key diagnostic criterion. Response to corticosteroids is generally favorable. This case highlights the importance of considering sarcoidosis in the differential diagnosis of parotid swelling, even in the absence of systemic signs, to ensure timely treatment and avoid unnecessary invasive procedures.

References

Ungprasert P, Crowson CS, Matteson EL. Clinical characteristics of sarcoid arthropathy: A population-based study. Arthritis Care Res (Hoboken). 2016;68(5):695-9.

Keywords

• Sarcoidosis
• parotid gland
• Non-caseous granulomas