Case Report: Clinical complete response of advanced renal cell carcinoma associated with Xp11.2 translocation/TFE3 gene fusion by treated by camrelizumab and axitinib: A rare case report

Abstract

Renal cell carcinoma (RCC) associated with Xp11.2 translocation/TFE3 gene fusions is a rare subtype of renal tumor. This entity predominantly occurs in juveniles, but rarely in adults. Xp11.2 translocation RCC (tRCC) patients with lymph node or organ metastasis are associated with poor prognosis, and the strategy remains controversial. Herein, we presented our experience with the diagnosis and treatment of an adult case of Xp11.2 tRCC. In our clinical practice, a 32-year-old male manifested fever and right flank paroxysmal blunt pain, and computed tomography showed an inhomogeneous mass, 6 cm in diameter, in the right kidney. Then right partial nephrectomy (PN) and renal hilar lymph node dissection by laparoscopic surgery were performed. Pathology revealed that the tumor cells were positive for TFE3 immunohistologically and positive for TFE3 break-apart fluorescence in situ hybridization assay. A splice site mutation c.1544-1G>T of protein tyrosine phosphatase receptor delta (PTPRD) was detected by next-generation sequencing and weak PTPRD expression was confirmed in tumor tissues compared to tumor periphery. This patient was diagnosed with stage III RCC and received immune checkpoint inhibitor (camrelizumab) in combination with tyrosine kinase inhibitor (axitinib) treatment for 1 year. He achieved a clinical complete response with no sign of recurrence or metastasis. PTPRD mutation might be a favorable indicator for Xp11.2 tRCC patients managed by PN and followed by the adjuvant therapy of immune checkpoint inhibitor and tyrosine kinase inhibitor.

Keywords: PD-1; PTPRD-mutation; Xp11.2 translocation renal cell carcinoma; immunotherapy; tyrosine kinase inhibitor.

FIGURE 1

Conventional CT and 3D reconstruction demonstrated a tumor and enlarged lymph nodes. (A) Abdominal CT scan detected a solid mass (6 cm in diameter) at the right kidney (red circle) and multiple enlarged lymph nodes (yellow circle). (B) 3D reconstruction of the urinary system which includes lesions (tumor: yellow; enlarged lymph nodes: orange), kidneys, collective system, and blood vessels. (C) A well-circumscribed solid mass on the right and multiple enlarged hilar lymph nodes scavenged on the left. (D) Cut surface of a well-encapsulated tumor lesion showing gray-white or gray-yellow and a large area of necrosis, and the tumor was 6 × 5.5 × 5 cm³ in size.

FIGURE 2

Representative images of the postoperative pathological features of the analyzed tumors. (A) HE (hematoxylin and eosin) staining of tumor sample, 200x. (B) HE staining of metastatic hilar lymph nodes sample, 200x. (C) Tumor cells display TFE3 nuclear positive. (D) TFE3 break-apart probe assay identified split signals, 1,000x. (E) Ki67 expression. (F) PAX-8 expression. (G) CD10 expression. (H) CD117 expression. (I) CA9 expression; (J) HMB45 expression (Images E-J have a magnification at 200x).

FIGURE 3

NGS-based identification of PTPRD mutation and PTPRD expression of the analyzed tumors. (A) NGS-based identification of the c.1544-1G>T mutation. (B) PTPRD expression in tumor sample (upper part) and tumor periphery (lower part), 200x.

FIGURE 4

A positron emission tomography-computed tomography (PET/CT) scan. (A) No suspicious primary lesion recurrence in the right kidney after surgery. (B) Neither lymph nodes enlargement adjacent to the aorta nor remote organ metastases.