title: Cystic Renal Oncocytoma and Tubulocystic Renal Cell Carcinoma: Morphologic and Immunohistochemical Comparative Study.
abstract: Renal oncocytoma (RO) may present with a tubulocystic growth in 3% to 7% of cases, and in such cases its morphology may significantly overlap with tubulocystic renal cell carcinoma (TCRCC). We compared the morphologic and immunohistochemical characteristics of these tumors, aiming to clarify the differential diagnostic criteria, which facilitate the discrimination of RO from TCRCC. Twenty-four cystic ROs and 15 TCRCCs were selected and analyzed for: architectural growth patterns, stromal features, cytomorphology, ISUP nucleolar grade, necrosis, and mitotic activity. Immunohistochemical panel included various cytokeratins (AE1-AE3, OSCAR, CAM5.2, CK7), vimentin, CD10, CD117, AMACR, CA-IX, antimitochondrial antigen (MIA), EMA, and Ki-67. The presence of at least focal solid growth and islands of tumor cells interspersed with loose stroma, lower ISUP nucleolar grade, absence of necrosis, and absence of mitotic figures were strongly suggestive of a cystic RO. In contrast, the absence of solid and island growth patterns and presence of more compact, fibrous stroma, accompanied by higher ISUP nucleolar grade, focal necrosis, and mitotic figures were all associated with TCRCC. TCRCC marked more frequently for vimentin, CD10, AMACR, and CK7 and had a higher proliferative index by Ki-67 (>15%). CD117 was negative in 14/15 cases. One case was weakly CD117 reactive with cytoplasmic positivity. All cystic RO cases were strongly positive for CD117. The remaining markers (AE1-AE3, CAM5.2, OSCAR, CA-IX, MIA, EMA) were of limited utility. Presence of tumor cell islands and solid growth areas and the type of stroma may be major morphologic criteria in differentiating cystic RO from TCRCC. In difficult cases, or when a limited tissue precludes full morphologic assessment, immunohistochemical pattern of vimentin, CD10, CD117, AMACR, CK7, and Ki-67 could help in establishing the correct diagnosis.
authors.affiliation: *Department of Pathology and Cytology, Clinical Center of the University of Sarajevo, Sarajevo, Bosnia and Herzegovina †Ljudevit Jurak Department of Pathology, Sestre milosrdnice Clinical Hospital Center ††Department of Pathology, University Hospital Dubrava, Zagreb, Croatia Departments of ‡Pathology ∥Urology, Charles University, Faculty of Medicine and University Hospital Plzeň ‡‡Biomedical Centre, Faculty of Medicine in Plzen, Charles University in Prague, Plzen, Czech Republic §Department of Pathology and Laboratory Medicine, Calgary Laboratory Services and University of Calgary, Calgary, AB, Canada ¶Department of Pathology, East University Riga, Riga, Latvia #Department of Pathology, Institute Nacional de Cancerologia **Department of Pathology, Centro Medico, Mexico City, Mexico.
authors.forename: Faruk
authors.initials: F
authors.lastname: Skenderi
authors.forename: Monika
authors.initials: M
authors.lastname: Ulamec
authors.forename: Semir
authors.initials: S
authors.lastname: Vranic
authors.forename: Nurija
authors.initials: N
authors.lastname: Bilalovic
authors.forename: Kvetoslava
authors.initials: K
authors.lastname: Peckova
authors.forename: Pavla
authors.initials: P
authors.lastname: Rotterova
authors.forename: Bohuslava
authors.initials: B
authors.lastname: Kokoskova
authors.forename: Kiril
authors.initials: K
authors.lastname: Trpkov
authors.forename: Pavla
authors.initials: P
authors.lastname: Vesela
authors.forename: Milan
authors.initials: M
authors.lastname: Hora
authors.forename: Kristyna
authors.initials: K
authors.lastname: Kalusova
authors.forename: Maris
authors.initials: M
authors.lastname: Sperga
authors.forename: Delia
authors.initials: D
authors.lastname: Perez Montiel
authors.forename: Isabel
authors.initials: I
authors.lastname: Alvarado Cabrero
authors.forename: Stela
authors.initials: S
authors.lastname: Bulimbasic
authors.forename: Jindrich
authors.initials: J
authors.lastname: Branzovsky
authors.forename: Michal
authors.initials: M
authors.lastname: Michal
authors.forename: Ondrej
authors.initials: O
authors.lastname: Hes
mesh_terms: D018249:Adenoma, Oxyphilic / Q000175:diagnosis* / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism*; D002292:Carcinoma, Renal Cell / Q000175:diagnosis* / Q000473:pathology; D048708:Cell Growth Processes; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007680:Kidney Neoplasms / Q000175:diagnosis* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D014407:Tumor Cells, Cultured; D014746:Vimentin / Q000378:metabolism*
chemical_list: D014408:Biomarkers, Tumor; D014746:Vimentin