Adult-onset renal cell carcinoma associated with Xp11.2 translocation/TFE3 gene fusion: 3 case reports and review of literature

Abstract

Rationale: Renal cell carcinoma associated with Xp11.2 translocations/TFE3 gene fusions is a rare subtype of renal cell carcinoma. This predominantly occurs in juveniles, but rarely seen in adults with lymph node or organic metastasis and a worsened prognosis.

Patients concerns: Herein, we presented 3 adult cases of Xp11-RCC. Two patients were in early stage and good condition, and the third patient had lymph node metastasis but showed no recurrence after a 3-month follow-up.

Diagnoses: Case 1: A 50-year-old female without any lumbago and gross hematuria was incidentally detected by left renal mass by ultrasonography. Case 2: A 31-year-old female with 2-year hemodialysis was detected with right renal carcinoma during preoperative examination of renal transplant. Case 3: A 45-year-old male with right lumbago for 1 month was detected with a mass in the lower pole of right kidney by ultrasonography.

Intervention: The characteristics of these 3 images are not consistent with each other, and showed some differences with the previous ones.

Outcomes: All these 3 patients underwent laparoscopic radical nephrectomy, and case 1 patient underwent renal hilar lymphnode dissection at the same time. Immunohistochemistry was performed on all the 3 tumors, revealing that the tumor cells were positive for TFE3 and Melan-A. Case 1 showed lymph node metastasis, and received mTOR inhibitors. The 3 patients had no recurrent and new metastasis in other organs after follow-up for 3 months, 2 months, and 11 months, respectively.

Lessons: Whether the adult-onset Xp-RCC has an aggressive clinical course still remains controversial. Characteristics of the images of the 3 adult cases showed some uniformity but still have some differences. Immunohistochemistry results revealed tumor cell positive for TFE3, but have no consistency in carbonic anhydrase IX, CD117, Ki67, CK8/18 AE1/AE3 and so on. Therefore, the uniform and definitive diagnostic standards of the tumors are uncertain. Hence, more cases and findings are required to elaborate the standards of all the tumor subtypes. Vascular endothelial growth factor-targeted therapy showed some efficacious results in patients with metastasis, but more useful treatments are warranted.

Figure 1

(A) A mixed density mass with a size of 7.9 × 7.6 cm and clear boundary in the lower left kidney were observed. Tumor attenuation (68 HU) was greater than renal parenchyma (33 HU) and medulla (28 HU) during CT plain scan. (B) and (C) There are slightly high and low density necrosis in the inferior plane of the tumor, revealing obvious uneven enhancement and the phenomenon contrast agent fast forward and fast out. The left renal pelvis oppressed by the tumor was unclear. After the peritoneum, the nodular shadow was seen in the retroperitoneal region, showing obvious inhomogeneous enhancement. The attenuation (98 HU in the arterial phase, 101 HU in the venous phase) was weaker than renal parenchyma (180 HU in the arterial phase, 202 HU in the venous phase) and medulla (142 HU in the arterial phase, 125 HU in the venous phase) in both arterial and venous phases. (D) and (E) The left kidney was with an irregular contour. In the upper left pole of the kidney, there were a mass of about 10.6 × 7.9 cm. This was mixed with a short T1 signal, and the internal signal was uneven. The vascular shadows and false envelop was observed in the tumor. Enlarged lymph nodes of about 2.3 cm were observed in the left renal hilar region. On MRI, the signal of the tumor was close to the renal cortex in the T1 and low signal intensity in T2.

Figure 2

(A) A solid cystic cystic and low density foci in the right kidney, and a nodular and slightly high density shadow within the foci were observed. The tumor contained the cystic part and solid part. During the CT plain scan, the solid part attenuation (53 HU) was greater than the cortex (34 HU) and medulla (32 HU), and the cystic part attenuation (16 HU) was smaller than the cortex (34 HU) and medulla (32 HU). (B) and (C) In the arterial and venous phases, the cystic part (26 HU in the arterial phase, 25 HU in the venous phase) of the tumor showed no enhancement, while the solid part of the attenuation (97 HU in the arterial phase, 83HU in the venous phase) was larger than the medulla (50 HU in the arterial phase, 68 HU in the venous), but lesser than the cortex (103HU in the arterial phase, 90 HU in the venous phase).

Figure 3

(A) A 5.2 × 4.9 cm round tumor, with clear boundary and uneven density was observed. The tumor attenuation was greater than that of the renal parenchyma and medulla. (B) and (C) In the arterial phase, the tumor enhancement (142 HU) was greater than the medulla (71HU) and lesser than the cortex (233 HU). In the venous phase, the tumor enhancement (116 HU) was weaker than the medulla (148 HU) and cortex (172 HU). (D), (E) and (F) The tumor showed low signal intensity in T1WI, lipid signal out of phase, and long signal in T2WI.

Figure 4

(A) Papillary cell arrangement, abundant cytoplasm, eosinophilic, hyaline nodules and psammoma bodies were observed. (B) The cystic part was encapsulated with friable mural nodules; (C) Positive cytoplasmic staining of TFE3; (D) Positive cytoplasmic staining of Melan-A.