Concurrent nodular lymphocytic myositis and myasthenia gravis. A case report

• Published in: Neuromuscular disorders : NMD 2024-12, Vol.45, p.105211, Article 105211
• Main Authors: D'Ambrosio, Eleonora S, Allen, Matti D, Ozes, Burcak, Sahenk, Zarife
• Format: Article
• Language: English
• ISSN: 0960-8966; 1873-2364; 1873-2364
• DOI: 10.1016/j.nmd.2024.105211

•Nodular lymphocytic myositis.•Myasthenia gravis.•CD3+ cells.•CD4+ cells.•CD163+cells. Localized painful nodules associated with focal myositis have been previously documented, either as isolated occurrences or in conjunction with systemic illnesses, such as polymyositis [1–4]. These nodules typically manifest over the course of 2-8 weeks and exhibit histological features consistent with inflammatory myositis. Here we present a unique case of a patient with a history of myasthenia gravis, who experienced exacerbation of myasthenic symptoms, accompanied by the development of palpable, tender nodules on her thighs and proximal weakness. Muscle biopsy revealed circumscribed mononuclear infiltrates predominantly composed of CD3+ and CD4+ lymphocytes. Furthermore, we detail the patient's rapid and sustained response to treatment with steroids (both intravenous pulse and maintenance therapy) and methotrexate. To the best of our knowledge, this represents the first documented case of nodular lymphocytic myositis concurrent with an exacerbation of myasthenia gravis, in a patient with no prior history of significant immunosuppression or chronic infection.