Fig. 4
Unusual morphologic appearance of common known TFE3 molecular subtype. a–d ASPSCR1-TFE3 renal cell carcinoma. Case 12 (a, b) demonstrated an infiltrative ductal pattern with desmoplastic response and hobnail cells are commonly found, resembling collecting duct carcinoma. Case 17 (c, d) was composed of extensive sclerosis, hyalinization, calcification, and ossification with clear to eosinophilic cells. e–h PRCC-TFE3 renal cell carcinoma. Case 10 (e, f) demonstrated more aggressive morphology, infiltrative growth pattern into the surrounding parenchyma, high-grade atypia, and prominent nucleoli. Case 13 (g, h) demonstrated predominant papillary structure lined by high columnar and overlapping cells with grooves, reminiscent of tall cell variant of papillary thyroid carcinoma. NONO-TFE3 renal cell carcinoma. Case 18 (i, j) demonstrated branching tubules and papillary structure, somewhat like ASPSCR1-TFE3 renal cell carcinoma. Melanocytic mesenchymal neoplasm with SFPQ -TFE3 gene fusion. Case 4 (k) demonstrated trabeculae and cords of epithelioid clear cells with small round nuclei. Immunohistochemistry for PAX8 (l) was negative
