Hereditary leiomyomatosis and renal cell cancer syndrome: A novel mutation in the FH gene

Benign metastasizing fumarate hydratase (FH)-deficient uterine leiomyomas: clinicopathological and molecular study with first documentation of multi-organ metastases

Leiomyoma is the most prevalent benign tumor of the female reproductive system. Benign metastasizing leiomyoma (BML) is a rare phenomenon that presents at distant sites, typically the lungs, exhibiting histopathological features similar to the primary uterine tumor in the absence of malignancy features in both. Fumarate hydratase-deficient uterine leiomyoma (FH-d UL) is an uncommon subtype among uterine smooth muscle tumors (0.5-2%), showing distinctive histomorphology and FH inactivation. The majority of FH-d ULs are sporadic, caused by somatic FH inactivation, while a minority of cases occur in the context of the hereditary leiomyomatosis and renal cell carcinoma (HLRCC) syndrome caused by germline FH inactivation. Metastasizing FH-d UL has not been well documented and might be under-reported. Here, we present two cases (21- and 34-year-old females) who presented with metastasizing FH-d UL after myomectomy/hysterectomy with histologically proven multiple lung metastases in both, in addition to multi-organ involvement in one case (cervical-thoracic lymph nodes, left kidney, perihepatic region, left zygomatic bone, and soft tissues). Pathological examination confirmed FH-d leiomyomas in the primary/recurrent uterine tumors, multiple lung lesions, and a renal mass. The minimal criteria for diagnosis of leiomyosarcoma were not fulfilled. Genetic testing revealed germline pathogenic FH variants in both cases (c.1256C > T; p.Ser419Leu in Case 1 and c.425A > G; p.Gln142Arg in Case 2). These novel cases highlight a rare but possibly under-recognized presentation of FH-d BML. Our study suggests that FH-d BML cases might be enriched for the HLRCC syndrome.

Hereditary Leiomyomatosis and Renal Cell Cancer (HLRCC): Report of a Family Pedigree

Hereditary leiomyomatosis and renal cell cancer (HLRCC) is a rare familial cancer syndrome with a germline mutation in the fumarate hydratase gene. Affected individuals are predisposed to development of cutaneous leiomyomas, uterine leiomyomas, and papillary renal cell carcinoma. We present a case of a mother and son pair affected with HLRCC, discuss clinical management, and examine potential syndromic manifestations in extended family members. Annual imaging surveillance for kidney cancer is recommended since 20-30% of individuals develop aggressive papillary type II renal cell carcinoma that can be difficult to treat once it has metastasized.