[Acute deterioration of myasthenia gravis in association with tuberculous mediastinal lymphadenitis, simulating recurrence of thymoma. A case report].

We reported a unique case of myasthenia gravis in association with tuberculous mediastinal lymphadenitis. A 56-year-old man suffering from generalized myasthenia gravis underwent thymothymectomy followed by good clinical recovery for 2 years. Thereafter, the patient complained of acute onset of ptosis, diplopia, dysphagia and limb weakness with elevated titers of serum anti-acetylcholine receptor antibody. CT scans of the chest showed a mediastinal lymphadenopathy and the Thallium-201 SPECT revealed an abnormal mediastinal accumulation, suggesting recurrence of thymoma in the mediastinal lymphonode. Histologically, the re-operated mediastinal tumor was of tuberculous lymphadenitis. This patient gives us a caution that we must guard against errors in differentiation between thymoma and tuberculous mediastinal lymphadenitis, particularly when myasthenic patients with mediastinal tumors are expected to receive the corticosteroids therapy. (120 words).