Melkersson-Rosenthal Syndrome (MRS): A Case Report.

Melkersson-Rosenthal syndrome (MRS) is a rare granulomatous disorder classically characterized by recurrent orofacial edema, relapsing peripheral facial palsy, and fissured tongue. However, the complete triad is uncommon, and incomplete forms may create a diagnostic challenge. We report the case of a 48-year-old man with type 2 diabetes mellitus who was admitted with recurrent swelling of both lips and a fissured tongue. The symptoms had begun 15 days earlier with an episode of bilateral macrocheilitis initially attributed to a food allergy. The swelling temporarily improved with antihistamine therapy but recurred one week later. Oral examination revealed marked bilateral lip edema, a fissured tongue, and gingival inflammation, without aphthous lesions, ulceration, xerostomia, or an obvious dental infectious focus. Neurological examination showed no evidence of peripheral facial palsy or facial sensory impairment. Laboratory investigations showed no major abnormalities. Serum calcium and angiotensin-converting enzyme levels were within normal limits. Thoracoabdominopelvic computed tomography and spirometry were unremarkable. QuantiFERON-TB Gold testing and sputum GeneXpert MTB/RIF were negative. A minor salivary gland biopsy was performed to assess granulomatous inflammation and demonstrated chronic non-caseating epithelioid and giant-cell granulomatous sialadenitis without histological evidence of malignancy. Based on the recurrent macrocheilitis, fissured tongue, and compatible granulomatous histology, an incomplete form of MRS was diagnosed. The patient received intralesional triamcinolone acetonide at a dose of 40 mg once monthly for six months, resulting in marked improvement in lip swelling. This case highlights the importance of considering an incomplete form of MRS in patients with recurrent unexplained lip swelling and fissured tongue, even in the absence of facial palsy.