Meningeal plasma cell granuloma in the early stage of relapsing polychondritis.

A 77-year-old man showed an asymptomatic meningeal lesion beneath the dura matter in the left fronto-parietal region on MRI during an examination for recurrent hoarsness. The lesion showed no gadolinium enhancement, and extended to neither the sulci nor skull. Neurological examinations revealed hoarseness, cochlear and vestibular dysfunction of the right ear, and mildly decreased Achilles tendon reflexes bilaterally. Laboratory findings showed marked inflammatory responses, but no abnormalities for LDH, IgG4, angiotensin-converting enzyme, or soluble IL-2 receptor. There was no serum monoclonal protein. Autoantibody panels in the serum were unremarkable except for an elevation of anti-type II collagen antibodies to a borderline value. Cerebrospinal fluid analysis disclosed an elevated protein concentration (152 mg/dl) and IgG index (1.41) with normal cell counts, negative results for bacterial/tubercular infection, and a normal cytology. 18F-fluorodeoxyglucose positron emission tomography showed increased uptake in the left frontal region (Max SUV: 7.54). Swelling of the vocal cord, arytenoid cartilage, false vocal cord, and vocal cord palsy on the right side were seen on laryngoscopy, all of which were ameliorated by dexamethasone administration. A meningeal biopsy contained the dura matter and arachnoid, in which a granulation composed of massive mature plasma cells with many Russel bodies, accompanied by occasional lymphocytes and histiocytes were observed. Three months after the biopsy, he developed bilateral auricular chondritis and conjunctivitis. Based on these findings, we diagnosed him with relapsing polychondritis (RP). Prednisolone administration (40 mg/day) improved the chondritis and meningeal lesion. Central nervous system involvement is rare in patients with RP, and meningeal complications, such as aseptic meningitis or pachymeningitis, are mostly observed after the diagnosis of RP. However, due to its rarity, it still remains to be clarified whether a similar pathogenesis of meningeal complications underlies RP. The present case is indicative in that predominant meningeal granuloma arose during chondritis of several portions that had gradually developed, which suggests that meningeal complications could be derived from RP.