Multidetector CT Characteristics of Fumarate Hydratase-Deficient Renal Cell Carcinoma and Papillary Type II Renal Cell Carcinoma

The Cytopathological Diagnosis of Fumarate Hydratase (FH)-Deficient Renal Cell Carcinoma in Two Patients With FH Gene Mutation

Fumarate hydratase-deficient renal cell carcinoma (FH-dRCC) is a high-grade renal cell carcinoma characterised by mutations in the FH gene. FH-dRCC is highly aggressive and has a poor prognosis, underscoring the importance of accurate diagnosis. Although the histopathological features of this neoplasm have been reported in previous studies, descriptions of its cytopathological features are limited. Here, we report the cytopathological morphologies of two cases of metastatic FH-dRCC in male patients aged 48 and 35 years. Case 1 presented with a cystic solid mass in the right retroperitoneal lumbar rib triangle region after the excision of a cystic tumour in the right kidney. Cytopathological examination of the fine-needle aspiration sample revealed papillary and tubular tumour cells. Case 2 developed abdominal ascites after bilateral nephrectomy, and cytopathological examination of ascitic fluid-characterised tumour cells with a high nuclear grade arranged in papillary and glandular patterns. In both cases, large tumour cells were observed with abundant eosinophilic cytoplasm, coarse chromatin and irregular nuclear shapes. Some cells exhibited characteristic eosinophilic macronucleoli and perinucleolar halos. Tumour cell clusters with a high nuclear grade, papillary structures, prominent eosinophilic macronucleoli and perinucleolar halos are the major cytopathological traits of FH-dRCC. CK7-negative/CA9-negative and PAX8-positive immunophenotypes may serve as important diagnostic markers. Moreover, the AKR1B10-positive/2SC-positive/FH-deficient immunophenotype contributes to the diagnosis of this tumour. Consequently, if the tumour cells have these characteristics, the diagnosis of FH-dRCC should be considered in cytology.

Metabolic tumor parameters on 18F-FDG PET/CT can predict the expression of PD-L1 and prognosis in patients with fumarate hydratase-deficient renal cell carcinoma

OBJECTIVE

This study aimed to comprehensively evaluate the performance of fluorine-18 fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) and investigate the association between metabolic parameters, programmed cell death ligand 1 (PD-L1) expression, and prognosis in patients with fumarate hydratase-deficient renal cell carcinoma (FHRCC).

METHODS

Twenty-nine patients with FHRCC were prospectively enrolled from May 2020 to February 2023 for 18F-FDG PET/CT. The maximum standardized uptake value (SUVmax), peak standardized uptake value (SUVpeak), metabolic tumor volume (MTV) and total lesion glycolysis (TLG) of primary/recurrent tumors were analyzed. The relationship between PET metabolic parameters, clinicopathological features and prognosis were evaluated.

RESULTS

Primary/recurrent and metastatic lesions showed FDG avidity, without metabolic differences between them. In our analysis, SUVmax of whole body (WB-SUVmax), SUVpeak of whole body (WB-SUVpeak), MTV of whole body (WB-MTV), and TLG of whole body (WB-TLG) were associated with the expression of PD-L1. The optimal cut-off values of WB-SUVmax, WB-SUVpeak, WB-MTV, and WB-TLG for predicting positive PD-L1 expression were 9.86 (AUC 0.814), 6.92 (AUC 0.848), 19.61 cm3 (AUC 0.803), and 58.39 g (AUC 0.841), respectively. Survival analysis further demonstrated that patients with WB-SUVpeak ≥ 8.92 had shorter time to progression than those with WB-SUVpeak < 8.92 (11.0 mo vs. 21.0 mo, P = 0.047).

CONCLUSIONS

18F-FDG PET/CT is effective in detecting FHRCC lesions due to their hypermetabolic nature. PET metabolic parameters can serve as predictors of positive PD-L1 expression, with higher values observed in FHRCC patients with positive PD-L1 expression. Additionally, WB-SUVpeak is a significant predictor of prognosis in patients with FHRCC.

The clinicopathologic and molecular features, and treatment outcome of fumarate hydratase-deficient renal cell carcinoma: a retrospective comparison with type 2 papillary renal cell carcinoma

BACKGROUND

To compare clinicopathologic, molecular features, and treatment outcome between fumarate hydratase-deficient renal cell carcinoma (FH-dRCC) and type 2 papillary renal cell carcinoma (T2 pRCC).

METHODS

Data of T2 pRCC patients and FH-dRCC patients with additional next-generation sequencing information were retrospectively analyzed. The cancer-specific survival (CSS) and disease-free survival (DFS) were primary endpoint.

RESULTS

A combination of FH and 2-succino-cysteine (2-SC) increased the rate of negative predictive value of FH-dRCC. Compared with T2 pRCC cases, FH-dRCC cases displayed a greater prevalence in young patients, a higher frequency of radical nephrectomy. Seven FH-dRCC and two T2 pRCC cases received systemic therapy. The VEGF treatment was prescribed most frequently, with an objective response rate (ORR) of 22.2% and a disease control rate (DCR) of 30%. A combined therapy with VEGF and checkpoint inhibitor reported an ORR of 40% and a DCR of 100%. FH-dRCC cases showed a shortened CSS (P = 0.042) and DFS (P < 0.001). The genomic sequencing revealed 9 novel mutations.

CONCLUSIONS

Coupled with genetic detection, immunohistochemical biomarkers (FH and 2-SC) can distinguish the aggressive FH-dRCC from T2 pRCC. Future research is awaited to illuminate the association between the novel mutations and the clinical phenotypes of FH-dRCC in the disease progression.

Factors influencing the detection rate of fumarate peak in 1H MR spectroscopy of fumarate hydratase-deficient renal cell carcinoma at 3 T MRI

AIM

To identify factors that may be associated with fumarate detection rate in 1H-magnetic resonance spectroscopy (MRS) in fumarate hydratase-deficient renal cell carcinoma (FH-RCC).

MATERIALS AND MEHODS

Between February 2018 and March 2022, 16 FH-RCC patients with 30 lesions underwent 1H-MRS. Detection results were classified as having a detected fumarate peak (n=12), undetected peak (n=10), or technical failure (n=8). Factors including tumour size, tumour location, treatment history, and metastasis status were collected and analysed. A Bayesian logistic regression model was applied to evaluate the association between these factors and the detection result.

RESULTS

Bayesian analysis demonstrated significant associations between fumarate detection results and the following factors: long-axis diameter (odds ratio [OR] of 1.64; 95% confidence interval [CI] of 1.07-2.53), short-axis diameter (OR of 1.90; 95% CI of 1.19-3.06), voxel size (OR of 2.85; 95% CI of 1.70-4.75), treatment history (OR of 0.35; 95% CI of 0.21-0.58), non-metastatic state (OR of 2.45; 95% CI of 1.48-4.06), and lymph node metastasis (OR of 0.35; 95% CI of 0.21-0.58). Technical failure results were associated with factors such as treatment history (OR of 2.59; 95% CI of 1.37-4.66), non-metastatic state (OR of 0.36; 95% CI of 0.19-0.66), and lymph node metastasis (OR of 2.61; 95% CI of 1.39-4.74).

CONCLUSION

Tumour size, treatment history, and metastasis character were associated with the detection of abnormal fumarate accumulation. This finding will serve as a reference for interpreting 1H-MRS results and for selecting suitable scenarios to evaluate FH-RCC.

The value of CT features and demographic data in the differential diagnosis of type 2 papillary renal cell carcinoma from fat-poor angiomyolipoma and oncocytoma

PURPOSES

To determine the CT features and demographic data predictive of type 2 papillary renal cell carcinoma (PRCC) that can help distinguish this neoplasm from fat-poor angiomyolipoma (fpAML) and oncocytoma.

METHODS

Fifty-four patients with type 2 PRCC, 48 with fpAML, and 47 with oncocytoma in the kidney from multiple centers were retrospectively reviewed. The demographic data and CT features of type 2 PRCC were analyzed and compared with those of fpAML and oncocytoma by univariate analysis and multiple logistic regression analysis to determine the predictive factors for differential diagnosis. Then, receiver operating characteristic (ROC) curve analysis was performed to further assess the logistic regression model and set the threshold level values of the numerical parameters.

RESULTS

Older age (≥ 46.5 years), unenhanced lesion-to-renal cortex attenuation (RLRCA) < 1.21, corticomedullary ratio of lesion to renal cortex net enhancement (RLRCNE) < 0.32, and size ≥ 30.1 mm were independent predictors for distinguishing type 2 PRCC from fpAML (OR 14.155, 8.332, and 57.745, respectively, P < 0.05 for all). The area under the curve (AUC) of the multiple logistic regression model in the ROC curve analysis was 0.970. In the combined evaluation, the four independent predictors had a sensitivity and specificity of 0.896 and 0.889, respectively. A corticomedullary RLRCNE < 0.61, irregular shape, and male sex were independent predictors for the differential diagnosis of type 2 PRCC from oncocytoma (OR 15.714, 12.158, and 6.175, respectively, P < 0.05 for all). In the combined evaluation, the three independent predictors had a sensitivity and specificity of 0.889 and 0.979, respectively. The AUC of the multiple logistic regression model in the ROC curve analysis was 0.964.

CONCLUSION

The combined application of CT features and demographic data had good ability in distinguishing type 2 PRCC from fpAML and oncocytoma, respectively.

Case report: Ultrasonographic findings of retroperitoneum and abdominal wall metastases of renal cell carcinoma with FH gene deletion

Renal cell carcinoma with FH gene deletion is a rare subtype of renal cell carcinoma. There had been few reports about ultrasonographic imaging of metastasis of renal cell carcinoma with FH gene deletion. This case reported one of the features of metastasis of renal cell carcinoma with FH gene deletion of a male patient 7 months after undergoing radical nephrectomy. He was diagnosed with a renal malignant tumor before the operation and confirmed to be primary FH gene-deficient renal cell carcinoma after undergoing radical nephrectomy in another hospital. Reexamination 7 months after the operation indicated that multiple metastases all over the body were found; therefore, he came to our hospital for further diagnosis and therapy. The tumors have metastasized in the lungs, bones, and lymph nodes adjacent to the left reproductive vessels and external iliac vessels, retroperitoneum, and abdominal wall so far as confirmed by PET/CT or MRI. Ultrasonographic findings of masses in the retroperitoneum and abdominal wall are fully discussed, which have been confirmed by biopsy and diagnosed as renal cell carcinoma with FH gene deletion by pathology.