Abstract
BackgoundFumarate hydratase-deficient renal cell carcinoma (FH-RCC) is a subtype of RCC that is increasingly recognized pathologically. The aim of this study was to evaluate the imaging features of FH-RCC on computed tomography (CT), magnetic resonance imaging (MRI), and fluorodeoxyglucose positron emission tomography (FDG PET), and to determine the pre-operative diagnostic potential of imaging.MethodsThis single-site retrospective study included patients with histologically confirmed FH-RCC or with a renal cancer and known germline FH mutation; imaging of the renal mass before treatment with contrast-enhanced CT, contrast-enhanced MRI, or FDG PET/CT between October 2007 and May 2019. Clinical information, pathological data, and imaging features were analyzed and reported descriptively.ResultsSixteen patients with sixteen tumors were included (median age 46 years, interquartile range 38–53 years; 31 % female). Almost all tumors were unifocal (15/16, 94 %). Most tumors had infiltrative margins (14/16, 88 %); few were circumscribed (2/16, 12 %). A large cystic tumor component (> 75 % of tumor volume) was seen in 8/16 (50 %) of tumors. Involvement of renal sinus fat was seen in 13/16 (81 %) of tumors, involvement of the hilar collecting system in 8/16 (50 %), and renal vein tumor thrombus in 6/16 (38 %). All 12 tumors (100 %) imaged with MRI had heterogenous tumor enhancement and heterogenous T2 signal. Of those patients that had diffusion-weighted imaging, 11/11 (100 %) of tumors had diffusion restriction in the solid portions of the tumor. Of the patients who had PET, 3/3 (100 %) tumors showed high metabolic activity with mean maximum standardized uptake value (SUVmax) of 16.4 (range 9.6–21.9). Patients presented with retroperitoneal nodal metastases in 69 % of cases and distant metastases in 75 %. Of those four patients without metastatic disease at presentation, three (75 %) developed metastases within 4 years of diagnosis.ConclusionsIn our study, the majority of tumors (≥ 75 %) were unifocal, had an infiltrative margin, invaded the renal sinus fat, and presented with distant metastases. On MRI, most tumors had heterogenous T2 signal and diffusion restriction in their solid components. The small number of cases that had PET imaging showed high metabolic activity.
Highlights
Fumarate hydratase deficient renal cell carcinoma (FHRCC) is a rare subtype of RCC
The purpose of this study was to document the imaging features of Fumarate hydratase-deficient renal cell carcinoma (FH-RCC) on computed tomography (CT), magnetic resonance imaging (MRI), and fluorodeoxyglucose positron emission tomography CT (FDG Fluorodeoxyglucose positron emission tomography (PET)/CT) in order that these may aid in the prospective identification of patients who may be at risk of hereditary leiomyomatosis and renal cell carcinoma (HLRCC) and a more aggressive disease course
The inclusion criteria for the study were (i) patient with a renal mass and presence of FH germline mutation, or a renal mass with FH loss and/or 2-succino-cysteine (2SC) positive immunoreactivity on IHC analysis, (ii) imaging of the renal mass before treatment with contrast-enhanced CT, contrast-enhanced MRI or FDG PET/CT, (iii) imaging study available in Digital Imaging and Communications in Medicine (DICOM) format through our institution’s picture archiving and communications system (PACS) and, (iv) imaging study performed between date range of 10/01/ 2007 and 05/01/2019
Summary
Fumarate hydratase deficient renal cell carcinoma (FHRCC) is a rare subtype of RCC. FH-RCC usually occurs in the context of hereditary leiomyomatosis and renal cell carcinoma (HLRCC) syndrome, an autosomal dominant disorder characterized by uterine and cutaneous leiomyomas and increased predisposition to an aggressive form of RCC [1]. HLRCC is caused by heterozygous germline mutations in the FH gene located on chromosome 1, which encodes FH, a critical component of the Krebs cycle [2, 3]. Since 2016, the World Health Organization classification of tumors of the urinary system has included HLRCC-associated RCC as a separate entity [6]. As opposed to HLRCC-associated RCC, less commonly, histologically indistinguishable tumors can arise from biallelic somatic loss of FH, without the germline mutations denoting HLRCC syndrome
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