We report a case of recurrent transverse myelitis (TM) associated with thymic follicular hyperplasia. The patient had six recurrences of TM over a 5 year period, her last attack leaving her with monoplegia of the right leg and significant loss of function in the other three extremities. A past history of pleuritis prompted a chest CT scan to look for evidence of pleuritis or sarcoidosis. Chest CT scan revealed a thymic mass. The patient underwent thymectomy following which she experienced resolution of her neurological symptoms and sustained recovery of function.

Thymomas comprise a histologically diverse set of tumours of the thymic epithelium whose neoplastic cells share morphological features with normal thymic epithelial cells.1 At diagnosis, a third are asymptomatic, a third are locally symptomatic having chest pain and the remaining third have myasthenia gravis (MG) which is by far the most common linked autoimmune disease.2

The causal link between thymoma and MG has yet to be fully elucidated. MG has only been associated with types A, AB, B1, B2 and B3 thymomas, which promote intratumorous T cell development and export these T cells to peripheral tissues.3 Thymic follicular hyperplasia (TFH) is the predominant thymus histological finding in MG and is seen in …