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Case Reports

Abstract

Hereditary Leiomyomatosis and Renal Cell Cancer (HLRCC) syndrome is an autosomal dominant disorder with a germline inactivating mutation in the fumarate hydratase (FH) gene, which presents with leiomyomatous tumors and renal cell carcinoma (RCC). Our case is of a 58-year-old Iranian female with a family history significant for multiple malignancies, and a personal history of uterine fibroids, with genetic testing of a pathogenic mutation in FH (C.267 plus 1G2C, spliced donor). Her son was also recently seen for multiple lipomas and found to share the same mutation. Recent MRI to evaluate for renal pathology showed a well-circumscribed hypermetabolic 1.9 x 1.6 x 1.4 cm exophytic mass arising from the left kidney, highly concerning for primary renal malignancy such as renal cell carcinoma, and an incidental 8 cm teratoma. The sections revealed a well circumscribed mass associated with the renal capsule that is comprised of fascicles of uniform, bland smooth muscle cells, consistent with leiomyoma. The tumor showed loss of immunohistochemical expression of fumarate hydratase. Four years later, the patient presents for evaluation of several tan, well circumscribed raised lesions on her left arm, chest, and back. The left upper arm, right and left anterior chest lesions were biopsied. The specimens revealed well circumscribed masses with bland smooth muscles cells, consistent with FH deficient pilar leiomyomas. This case represents an unusual presentation of HLRCC due to the presence of a leiomyomas, particularly involving the kidney, with the absence of a low-grade oncocytic RCC expected to be seen in patients with this germline mutation.