Cyto‐histological correlation of Xp11.2 translocation/TFE3 gene fusion associated renal cell carcinoma: Report of a case with review of literature

Abstract

The MiT family translocation renal cell carcinomas (RCCs) are relatively rare in comparison to the conventional RCC. The cytologic features overlap with conventional clear cell RCC and papillary RCCs, thereby making the diagnosis extremely challenging. Here, we describe a case of TFE3 translocation associated RCC in a 58-year-old patient, with emphasis on cytomorphologic features and clues toward this diagnostic entity. Correlating the cytohistologic findings and review of touch imprints revealed that presence of hyaline nodules resembling leisegang rings and psammoma bodies in cytologic smears from kidney tumors serve as an important clue in raising a suspicion for the diagnosis of MiT family translocation RCCs.

New entities, new technologies, new findings: A review of the cytologic features of recently established subtypes of renal cell carcinoma

“…It is noteworthy that, when performed, the melanocytic markers Melan A and HMB45, as well as cathepsin K, were negative . Most specific, TFE3 was positive in all cases tested, and molecular confirmation was obtained in 4 cases …”

“…The t(6;11) RCC subtype has a distinctive biphasic morphology, consisting of the nested or solid growth of large epithelioid cells with ample cytoplasm and round, small nuclei interspaced with smaller cells that have hyperchromatic nuclei forming rosette‐like structures around basement membrane‐like material. However, the second cell population may be not present, very focal, or present as an overlapping feature in Xp11 translocation RCC . Xp11 ASPL ‐ TFE3 translocation RCC is characterized by a papillary or nested pattern, often with psammomatous calcifications, of large epithelioid cells with abundant clear‐to‐oncocytic cytoplasm and high‐grade nuclei.…”

“…Overall, through their variety of patterns and morphologic features, the cytologic interpretation raised the suspicion for RCC, favoring clear cell, papillary, or an unusual type. In one instance, the presence of a putative second population of smaller cells distributed around acellular hyaline globules raised upfront the possibility of t(6;11) RCC …”

“…However, the second cell population may be not present, very focal, 45 or present as an overlapping feature in Xp11 translocation RCC. 44,46 Xp11 ASPL-TFE3 translocation RCC is characterized by a papillary or nested pattern, often with psammomatous calcifications, of large epithelioid cells with abundant clear-to-oncocytic cytoplasm and high-grade nuclei. PRCC-TFE3 translocation RCC has a more nested growth pattern of cells, sometimes papillary or solid, with less cytoplasm, often lower nuclear grade features, and fewer psammomatous calcifications.…”

“…In one instance, the presence of a putative second population of smaller cells distributed around acellular hyaline globules raised upfront the possibility of t(6;11) RCC. 46 An analysis of voided or catheterized urine also was very interesting, 54,55 with cytospin slides revealing variably sized papillary clusters along with large cells that had clear-to-eosinophilic cytoplasm. Despite the presence of papillary clusters, the cytologic interpretations did not favor urothelial carcinoma, which was excluded with an UroVysion test in one instance.…”