ALK-rearranged renal cell carcinoma

Definition: ALK-rearranged renal cell carcinoma (ALK-RCC) has been proposed and incorporated into the World Health Organisation Classification of renal tumours as a provisional entity.

ALK-RCC accounts for less than 1% of all renal tumours. The age of patients ranges from 6 to 61 years with a mean age of 29.6 years.

Grossly, the tumour forms were ill-demarcated or well demarcated solid mass in the renal medulla. Histologically, RCC with VCL-ALK translocation resembles renal medullary carcinoma and mucinous cribriform pattern, signet-ring cell pattern and solid rhabdoid pattern are often observed in RCC with non-VCL-ALK fusion.

Immunohistochemically, ALK protein diffusely expresses and TFE3 is often expressed. ALK gene can fuse to VCL, TPM3, EML4, HOOK1 or STRN gene.

A break-apart fluorescence in situ hybridisation study is clinically available for the practice of definite diagnosis.

ALK inhibitor therapy will provide great benefit for patients with advanced stage of ALK-RCC.

Open references

 A review of ALK-rearranged renal cell carcinomas with a focus on clinical and pathobiological aspects. Kuroda N, Sugawara E, Kusano H, Yuba Y, Yorita K, Takeuchi K. Pol J Pathol. 2018;69(2):109-113. doi : 10.5114/pjp.2018.76693 PMID: 30351856

 The classification of pediatric and young adult renal cell carcinomas registered on the children’s oncology group (COG) protocol AREN03B2 after focused genetic testing. Cajaiba MM, Dyer LM, Geller JI, Jennings LJ, George D, Kirschmann D, Rohan SM, Cost NG, Khanna G, Mullen EA, Dome JS, Fernandez CV, Perlman EJ. Cancer. 2018 Aug;124(16):3381-3389. doi : 10.1002/cncr.31578 PMID: 29905933