Immunohistochemical Panel for Differentiating Renal Cell Carcinoma with Clear and Papillary Features

Abstract

Renal cell carcinoma (RCC) in which clear cells with papillary architecture are present is a difficult diagnostic challenge. The most common type, clear cell RCC, only rarely has papillary architecture. The second most common one, papillary RCC, only rarely contains clear cells. However, two recently described less-common types, clear cell papillary and Xp11 translocation RCC characteristically feature both papillary architecture and cells with clear cytoplasm. Accurate diagnosis has both prognostic and therapeutic implications. This study aims to highlight the helpful cytomorphologic and immunohistochemical features of each of these entities to enable reproducible classification. Sixty RCC cases with clear cells and papillary architecture were selected and classified according to The International Society of Urological Pathology (ISUP) Vancouver Classification of Renal Neoplasia and graded according to The International Society of Urological Pathology (ISUP) grading system for renal cell carcinoma then stained for CK7, carbonic anhydrase IX (CA IX), α-methylacyl-CoA-racemase (AMACR) and TFE-3. The characteristic immunoprofile of Clear RCC is CK7-, AMACR-, CA IX+ and TFE3-, papillary RCC is CK7+, AMACR+, CAIX- and TFE3-, while for clear cell papillary RCC it is CK7+, AMACR-, CAIX+ and TFE3- and lastly Xp11translocation RCC is CK7-, AMACR+, CAIX- and TFE3+. Immunohistochemical staining for CA IX, CK7, AMACR and TFE3 comprises a concise panel for distinguishing RCC with papillary and clear pattern.

Cutaneous metastases of papillary renal cell carcinoma: A case report and review of the literature

“…10 which is expressed in all RCC subtypes and has a sensitivity of approximately 95%, was a diagnostic clue of the renal origin of the tumor. 11 In recent times, PAX8 has emerged as the most useful marker for…”

Clear Cell Papillary Renal Cell Carcinoma

“…17 On the other hand, the tumor is generally negative for CD10, RCC antigen, AMACR, TFE3, and translocation factor EB (TFEB). Therefore, ccpRCC has a unique immunohistochemical phenotype (CK7 þ , CA IX þ [cuplike], AMACR À , 34bE12 þ , CD10 À , TFE3 À ), 1,10 which allows differentiation of this tumor from other types of renal cancer with overlapping histologic features.…”

“…Clear cell RCC is the most common variant of RCC (70%). 1,10 Grossly, the cut surface typically looks yellow, often with cysts, hemorrhage, and necrosis. Tumor cells commonly have clear cytoplasm, and can have cystic, solid areas, like ccpRCC, but papillary areas are uncommon.…”

“…4 Papillary RCC is the second most common variant of RCC (18%). 1,10 It often presents as a well-circumscribed tumor with a fibrous pseudocapsule, and a variable cut surface with areas of hemorrhage, necrosis, and cystic degeneration. Most PRCCs have papillary architecture with delicate fibrovascular cores, which often contain foamy macrophages, hemosiderin, and psammoma bodies.…”

“…In equivocal cases, a number of immunohistochemical stains will aid in arriving at the correct diagnosis, including cytokeratin 7 (CK7), a-methylacyl-CoA racemase (AMACR), carbonic anhydrase IX (CA IX), CD10, and transcription factor E3 (TFE3). 10…”