Thymolipoma in patients with myasthenia gravis: report of two cases and review

Abstract

Two cases of simultaneous occurrence of myasthenia gravis (MG) and thymolipoma are described and 4 previously reported cases are reviewed. In all 6 cases, thymectomy was performed. Pre- and postoperatively, the clinical status of the patients was similar to that of late-onset MG without thymolipoma. It is possible that simultaneous occurrence of MG and thymolipoma may be coincidental.

Thymolipoma. A report of nine cases, with emphasis on its association with myasthenia gravis

“…Other studies have noted a similar phenomenon. The study of Pan et al, 7 which includes a thorough review of the literature, showed patients with thymolipomas and myasthenia gravis are often older than 50 years with tumors weighing less than 100 g. In contrast to thymomas, which sometimes show malignant behavior, thymolipomas are benign tumors that do not infi ltrate adjacent organs and do not metastasize. Thymomas are epithelial neoplasms, often exhibiting organotypic architectural features, and they are variably admixed with T lymphocytes.…”

“…The number of myasthenia gravis patients with a thymolipoma varies considerably, with a maximum of up to 50%. 1,[7][8][9] Since most studies investigate only a limited number of cases, there are no reliable data. Improvement of myasthenia gravis within several months after the removal of the tumor has been reported.…”

“…6,7,9,26 In cases of large tumors, the symptoms included cough, dyspnea, chest pain, hoarseness, and cyanosis. Many tumors are detected due to paraneoplastic symptoms, as shown in the current series.…”

“…[4][5][6] The incidence of myasthenia gravis associated with thymolipomas is between 2.8% and 50%. [7][8][9] The symptoms of myasthenia gravis may improve after the resection of the tumor in some patients. 9 In rare cases, a thymolipoma may be associated with thymoma or thymic malignant lymphoma.…”

Thymolipoma associated with myasthenia gravis

“…4 Verbist et al commented that because the tumor contained a germinal center in their case the association of myasthenia gravis and thymolipoma was incidental. 5 Pan et al 6 and Alfaro et al 7 noted that the simultaneous occurrence of myasthenia gravis and thymolipoma may be coincidental. In the present case, thymic tissue in the tumor had no germinal centers, and adipose tissue surrounding the tumor contained islands of thymic tissue, so a causal relation between the thymolipoma and myasthenia gravis was not confirmed.…”