A case of hepatocellular carcinoma presenting with myasthenia gravis (P5.4-031)

Objective: To describe a case of hepatocellular carcinoma presenting with myasthenia gravis Background: The association of Myasthenia Gravis (MG) with thymomas and thymic hyperplasia is well known. However, MG with extrathymic malignancy is much less common; cases of MG associated with hepatocellular carcinoma (HCC) are even more rare. Design/Methods: We evaluated an individual in the hospital that presented with MG and was subsequently found to have HCC. A literature review of the incidence and pathophysiology of MG associated with extrathymic malignancies was performed as well. Results: We report the case of a 73-year-old right handed male with a past medical history of psoriasis, hypertension, and type 2 diabetes mellitus who presented with a 5-month history of progressive dysphagia, dysarthria, and 40-pound weight loss. His initial exam revealed labial and lingual dysarthria with prolonged speech and bilateral ptosis which improved with ice pack test. There was no fatigability of his axial muscles or ophthalmoplegia. His serum was positive for acetylcholine receptor binding, blocking and modulating antibodies, along with greater than 10% decline in compound muscle action potential (CMAP) amplitude on repetitive nerve stimulation testing. CT Chest did not show thymoma or thymic hyperplasia. He was treated with 5 days of intravenous immunoglobulin (IVIG) and started on maintenance pyridostigmine with some improvement in his bulbar symptoms. Further workup revealed multiple large hepatic lesions confirmed to be HCC after surgical biopsy. He was discharged home with plans to follow up with regional cancer center for further treatment. Conclusions: While myasthenia gravis associated with extrathymic malignancies is not uncommon, its association with hepatocellular carcinoma is infrequently reported and may be suggestive of an alternative immune-mediated pathophysiology. Disclosure: Dr. Fussner has nothing to disclose. Dr. Garg has nothing to disclose. Dr. Sharp has nothing to disclose.