Morphological spectrum of Xp11. Translocation-Associated Renal Cell Carcinoma in a Developing Country

Objective: to determine unusual morphological features and a panel of immunohistochemical markers to diagnose Xp11 translocation carcinoma. Study Design: Retrospective longitudinal study. Place and Duration of Study: Shaukat Khanum Memorial Cancer Hospital, Lahore Pakistan, from Jun 2015 to Feb 2020. Methodoldogy: We analyzed clinicopathological features, and evaulated intensity and extent of TFE 3 immunoreactivity of 18 cases with suggested diagnosis of xp11 translocation associated renal cell carcinoma from 2015-2020. Results: Different morphological pattern includes papillary (8/18, 44%), nested (2/18, 11.1%), alveolar (3/18, 16.7%), nested and papillary (3/18, 16.7%), solid and nested (1/18, 5.6%), cystic and nested (1/18, 5.6%). Four cases show papillary architecture with a linear array of nuclei away from the basement membrane, a pattern seen in SFPQ-TFE3 renal cell carcinoma and NONO-TFE3 renal cell carcinoma. Strong nuclear TFE3 expression was seen in 9/18 (50%) cases. Cathepsin k expression was seen in 6/11 (54%) cases, Ck7 was focal weak positive in 4/12 (25%) cases, PAX8 was positive in 8/8 (100%) cases, and CA IX was focal weak positive in 1/5 (20%) case. According to follow-up data, disease progression was seen in only one case with the low-stage disease. No death was reported due to renal cell carcinoma to date of follow-up. Conclusion: We have suggested that young patient age, unusual morphological features and an immunohistochemical panel may help reach the diagnosis in countries with limited resources.