Cardiac Myxoma Caused by Fumarate Hydratase Gene Deletion in Patient With Cortisol-Secreting Adrenocortical Adenoma

Abstract Context Germline mutations in fumarate hydratase (FH) gene are known to cause hereditary leiomyomatosis and renal cell carcinoma (HLRCC) and are occasionally accompanied with cutaneous and uterine leiomyoma or cortisol-producing adrenocortical hyperplasia. However, the association between FH mutations and cardiac or adrenocortical tumors has remained unknown. Here, we identified a novel deletion in FH, exhibiting cardiac myxoma and subclinical Cushing syndrome due to adrenocortical tumor. Case Description A 44-year-old man was referred to our hospital for cardiac and adrenal tumor evaluation. He had a history of multiple painful, dermal papules and nodules diagnosed as cutaneous leiomyoma. The surgically resected cardiac tumor was diagnosed as myxoma. The adrenal tumor was clinically diagnosed as subclinical Cushing syndrome. Laparoscopically resected adrenal tumor was pathologically diagnosed as adrenocortical adenoma harboring unique histological findings similar to primary pigmented nodular adrenocortical disease (PPNAD). DNA analysis revealed a germline deletion in FH c0.737delT (p. Phe225Leufs*31) and loss of heterozygosity (LOH) in cardiac myxoma. As a functional analysis of FH in cardiac myxoma, low FH protein expression with elevated 2-succinocysteine (2SC), a marker of FH dysfunction, was immunohistochemically detected. However, in adrenocortical tumor, LOH of FH was not detected, and FH or 2SC expression was not altered. Conclusions This is the first case of HLRCC complicated by cardiac myxoma. LOH of FH deletion and its dysfunction were identified in cardiac myxoma. The association between FH deletion and adrenocortical lesion, however, needs to be further clarified.