[Relapsing, therapy refractory episcleritis, paraproteinemia and cutaneous-subcutaneous nodules on arm and hip: manifestations of a necrobiotic xanthogranuloma (NXG)].
BACKGROUND: Necrobiotic xanthogranuloma is a rare granulomatous disease featuring nodular, sometimes ulcerating, skin lesions in association with paraproteinemia and variable organ disease. Eye involvement manifests itself often as periorbital plaque-like infiltrates but also as chronic episcleritis, conjunctivitis, keratitis and scleritis. CASE REPORT: A 49-year-old female patient presented to our hospital with a seven-year history of relapsing bilateral episcleritis refractory to treatment. Her past medical history included an IgG paraproteinemia and C4-deficiency of unknown etiology. A year prior to presentation the patient had undergone biopsy of a skin nodule on her arm which histologically was suspected to be an infectious granuloma. A recurrence of the lesion at the site of biopsy together with a new nodule on the hip prompted us to perform further histological analyses. RESULTS: The histological specimen displayed numerous giant cells of the foreign body and Touton type, some xanthomatous foam cells with cholesterol clefts and collagen necrosis, leading to the diagnosis of NXG. As part of the disease, serology showed an IgG lambda paraproteinemia, elevated cANCA values, a C4 deficiency and a negative rheumatoid factor. No other immunological dysfunction was detected. CONCLUSIONS: NXG is a severe multi-system disorder that may cause various chronic inflammatory conditions of the eye's anterior segment. Its early diagnosis is mandatory as potentially fatal organ complications may arise and the association with lymphoproliferative diseases has been described. Due to the relative rarity of the disease no binding therapeutic regimen exists. Options include alkylating agents in combination with corticosteroids, plasmapheresis and subcutaneous interferon alfa-2 b.