D2.47 - Unmasking Melkersson-Rosenthal Syndrome: Diagnostic Challenges in a Patinent Pressenting With Angioedema

Melkersson-Rosenthal syndrome (MRS) is a rare systemic granulomatous entity. It is classically defined by the triad: recurrent orofacial edema, peripheral facial paralysis, and fissured tongue. However, the complete presentation is unusual (8-18%), with oligosymptomatic forms or isolated granulomatous cheilitis (Miescher's cheilitis) predominating. Although its etiology is uncertain, a genetic predisposition and immunological factors are postulated to condition non-caseating granulomatous inflammation.

We present the case of a 34-year-old male of Colombian origin, with a history of allergic rhinitis due to dust mites. He was referred to the Allergy Department due to episodes of lower lip edema of 4 months' duration, associated with pruritus, a burning sensation, and pain. Symptoms did not improve with oral antihistamines or topical corticosteroids. Upon examination, labial swelling with scaling and the presence of a fissured tongue were notable. No neurological symptoms or edema in other locations were observed.

Complementary tests (complete blood count, biochemistry, complement fractions, coagulation, and chest X-ray) were normal. A lower lip biopsy was performed, revealing a perivascular and interstitial lymphohistiocytic infiltrate with the formation of non-necrotizing granulomas. Immunohistochemical techniques for infectious agents (PAS, Grocott, Ziehl-Neelsen, and MTB-RT) were negative, confirming the diagnosis of MRS in its oligosymptomatic form.

The diagnosis of MRS is eminently clinical, although histopathology is key to ruling out differential diagnoses such as sarcoidosis, Crohn's disease, or hereditary angioedema. Although its complete presentation only occurs in 8-25% of patients. It is common to find oligosymptomatic forms, where persistent labial swelling known as Miescher's cheilitis is usually the most prevalent initial manifestation. The treatment of choice is systemic corticosteroids to reduce inflammation and prevent fibrous induration secondary to the granulomatous infiltrate.

MRS should be systematically considered in the differential diagnosis of recurrent angioedema, especially in cases refractory to conventional therapy. The presence of signs such as fissured tongue and the anatomopathological study are fundamental tools for an early diagnosis and the adequate management of this pathology.