COW-2021-51

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Xp11 translocation associated renal cell carcinoma, melanotic

Tumor cells were strongly and diffusely positive for PAX8 and TFE3. The neoplasm also expressed cytokeratin 7,alpha-methylacyl-CoA racemase,Melan-A (focally) and HMB-45 (focally). Carbonic anhydrase IX was expressed in focal areas, mainly at the tip of some papillae.

Xp11 translocation renal cell carcinoma accounts for 40% of pediatric renal cell carcinomas(RCCs) and 2-4% of adult RCCs (1). Nodal metastases are common at presentation. Xp11 translocation renal cell carcinoma should be considered in the differential diagnosis of clear cell neoplasms in the kidney. It may show overlapping features of some common types of RCCs such as (conventional)clear cell RCC, oncocytoma, epithelioid angiomyolipoma and multilocular cystic renal neoplasm of low malignant potential. Distinctive features that raise suspicious for Xp11 RCC are papillary growth with a combination of epithelioid clear and eosinophilic cells, abundant psammoma bodies, and cells with voluminous or “ballooned out” appearance (1,2). These neoplasms may contain melanin pigment (1) and it may be a such striking feature that may result pigmented / black tumors at gross examination (3-5). A prominent pigmented component should prompt the pathologist to work in the differential diagnosis with PEComa.

In 2009, Argani and colleagues reported two cases of melanotic renal neoplasms with TFE3 gene fusions and overlapping features between Xp11 RCCs and PEcomas: epithelioid tumor with melanin content, and no expression of cytokeratins, PAX8 or smooth muscle markers(3). Since then, a total of 19 cases of melanotic Xp11 RCCs have been documented in English literature(4). In addition to obvious epithelial and papillary morphology of our case, strong and diffuse expression of cytokeratin 7 (an unusual but well documented feature for Xp11 RCC) and PAX8 were important cluesto the differential diagnosis with melanotic Xp11 PEComa / alveolar soft part sarcoma (6,7).

Our case was notably small (0.8 cm) and diagnosed as an incidental finding in imaging exams. The frequency of Xp11 RCCs diagnosed as incidental renal masses ranges from 24% to 52% in different series (8-10).

1.Moch H, Humphrey PA, Ulbright TM, Reuter V (2016) WHO classification of tumoursof the urinary system and male genital organs. International Agency for Research on Cancer, Lyon. Pgs: 33-34.

2.Athanazio DA., Amorim LS, da Cunha IW, et al (2021).Classification of renal cell tumors –current concepts and use of ancillary tests: recommendations of the Brazilian Society of Pathology.Surg Exp Pathol4:,4. 3.Argani P, Aulmann S, Karanjawala Z, Fraser RB, Ladanyi M, Rodriguez MM. Melanotic Xp11 translocation renal cancers: a distinctive neoplasm with overlapping features of PEComa, carcinoma, and melanoma. Am J Surg Pathol. 2009 Apr;33(4):609-19

4.Jing H, Wei H, Yuan H, Li Y, Li N, Mu D. Melanotic Xp11 translocation renal cancer: a report of a distinctive case and a review of the literature. Diagn Pathol. 2018 Aug 13;13(1):51

5.Varinot J, Camparo P, Beurtheret S, Barreda E, Compérat E. An adult case of melanotic Xp11 translocation renal cancers: distinct entity or sub-entity? Int J Surg Pathol. 2011 Jun;19(3):285-9.

6.Trpkov K, Hes O, Williamson SR, Adeniran AJ, Agaimy A, Alaghehbandan R, Amin MB, Argani P, Chen YB, Cheng L, Epstein JI, Cheville JC, Comperat E, da Cunha IW, Gordetsky JB, Gupta S, He H, Hirsch MS, Humphrey PA, Kapur P, Kojima F, Lopez JI, Maclean F, Magi-Galluzzi C, McKenney JK, Mehra R, Menon S, Netto GJ, Przybycin CG, Rao P,Rao Q, Reuter VE, Saleeb RM, Shah RB, Smith SC, Tickoo S, Tretiakova MS, True L, Verkarre V, Wobker SE, Zhou M, Gill AJ. New developments in existing WHO entities and evolving molecular concepts: The Genitourinary Pathology Society (GUPS) update on renal neoplasia. Mod Pathol. 2021 Jul;34(7):1392-1424

7.Wang XT, Fang R, Zhang RS, Ye SB, Li R, Wang X, Pan R, Liu C, Chen JY, Zhao M, Teng XD, Yu WJ, Li YJ, Wang FH, Zhang JG, Yang QC, Zhang YS, Lu ZF, Ma HH, Zhou XJ, Xia QY, Rao Q. Malignant melanotic Xp11 neoplasms exhibit a clinicopathologic spectrum and gene expression profiling akin to alveolar soft part sarcoma: a proposal for reclassification. J Pathol. 2020 Aug;251(4):365-377.

8.Lim B, You D, Jeong IG, Kwon T, Hong S, Song C, Cho YM, Hong B, Hong JH, Ahn H, Kim CS. Clinicopathological features of Xp11.2 translocation renal cell carcinoma. Korean J Urol. 2015 Mar;56(3):212-7.

9.Kuthi L, Somorácz Á, Micsik T, Jenei A, Hajdu A, Sejben I, Imre D, Pósfai B, Kóczián K, Semjén D, Bajory Z, Kulka J, Iványi B. Clinicopathological Findings on 28 Cases with XP11.2 Renal Cell Carcinoma. Pathol Oncol Res. 2020 Oct;26(4):2123-2133

10.Ma W, Liu N, Zhuang W, Li W, Qu F, Sun J, Xu W, Zhang L, Jia R, Xu L, Zhao X, Li X, Zhang G, Guo H, Li D, Gan W. Comparative Clinicopathologic Characteristics and Outcomes of Paediatricand Adult Xp11 Translocation Renal Cell Carcinomas: a Retrospective Multicentre Study in China. Sci Rep. 2020 Feb 10;10(1):2249.

Suelen Cunha Santana
Federal University of Bahia / Hospital Universitário Professor Edgard Santos Salvador, Bahia, Brazil

Maria Estela Pompeu do Amaral and Daniel Athanazio
Imagepat, Laboratory of Pathology
Federal University of Bahia / Hospital Universitário Professor Edgard Santos, Salvador, Bahia, Brazil

Kidney

Kidney Neoplasms, Xp11 translocation associated renal cell carcinoma, Melanin