Prognosis and Clinicopathological Characters of Adult TFEB-Altered Renal Cell Carcinoma: A Single Center Experience of 18 Cases

TFEB-altered RCC is a rare entity whose therapeutic implications and long-term survival remain unclear, especially for metastatic cases. In this study, we reported the clinicopathologic and radiological features of eighteen novel TFEB-altered RCC cases and found that TFEB-altered RCC exhibited mixed morphological and radiological characteristics. For metastatic TFEB-altered RCC, immunotherapy-based drug combinations could be a promising treatment strategy. Introduction: TFEB-altered renal cell carcinoma (RCC) is a rare entity characterized by the rearrangement of the TFEB gene or TFEB amplified. The therapeutic implications and long-term survival of TFEB-altered RCC remain unclear, especially for metastatic cases. Materials and Methods: The current study initially enrolled 7604 consecutive RCC patients at our center and a total of 248 patients were selected for FISH and immunohistochemistry (IHC) analysis. Eventually, eighteen TFEB-altered RCC patients were identified. We then reported the clinical, morphological, IHC, and radiological features of these cases. Results: The median age at initial diagnosis was 45 years, ranging from 18 years to 66 years. The majority of the TFEB-altered RCC patients were male (61.1%), with localized disease (T1-2N0M0, 77.8%). The median split TFEB fluorescent signal was 24%, ranging from 15%-80%. The morphological characteristics of TFEB-altered RCC were variable, with acinar, papillary, solid, or nest patterns. IHC and magnetic resonance imaging features of TFEB-altered RCC were nonspecific. Nine patients with localized disease received partial nephrectomy and five patients with localized disease received radical nephrectomy. During the median follow-up of 67 months, no signs of recurrence or metastasis were found in these patients. Two patients had distant metastasis and received axitinib plus PD -1 immunotherapy. One of them died at 40-month follow-up and another still alive at 88-month follow-up. Conclusion: TFEB-altered RCC is an extremely rare variant, exhibited mixed morphological characteristics. The radiological feature lack specificity, resembling clear cell RCC or papillary RCC. Genetic analyses including FISH analysis is crucial in the diagnosis of TFEB-altered RCC. For localized TFEB-altered RCC, both radical nephrectomy and partial nephrectomy conferred satisfactory prognosis. For metastatic TFEB-altered RCC, immunotherapy-based drug combinations could be a promising treatment strategy.