Renal Splenosis: Renal Mass Biopsy Diagnosis of a Tumor Clinically Mimicking Renal Cell Carcinoma

Document Type

Article

Publication Date

4-1-2017

Publication Title

Applied immunohistochemistry & molecular morphology

Keywords

Aged, Biomarkers, Biopsy, Needle, CD8 Antigens, Carcinoma, Renal Cell, Diagnosis, Differential, Epithelial Cells, Humans, Immunohistochemistry, Kidney, Kidney Neoplasms, Male, Splenosis

Abstract

Renal mass biopsy is increasingly used to guide conservative tumor management, placing increasing importance on pathologists' ability to diagnose small tumor samples. A 66-year-old man with a history of prior splenectomy for trauma presented for urologic evaluation after identification of a left 5.8 cm renal mass. Partial envelopment of the mass by renal parenchyma and equivocal enhancement on computed tomography raised concern for renal cell carcinoma. Needle-core biopsy revealed blood, subtle vasculature, few aggregates of lymphocytes, and rare renal tubules. Immunohistochemical staining revealed CD8-positive sinusoids but negative reactivity for epithelial antigens (PAX8, keratin, epithelial membrane antigen, carbonic anhydrase IX), supporting diagnosis of renal splenosis. Renal splenosis is a rare phenomenon that can form a sizeable intrarenal mass, mimicking renal cell carcinoma. Pathologists' awareness of this uncommon occurrence may avoid unnecessary surgery. CD8-positive sinusoids and negative epithelial markers are helpful confirmatory features in the biopsy setting.

Medical Subject Headings

Aged; Biomarkers; Biopsy, Needle; CD8 Antigens; Carcinoma, Renal Cell; Diagnosis, Differential; Epithelial Cells; Humans; Immunohistochemistry; Kidney; Kidney Neoplasms; Male; Splenosis

PubMed ID

27028241

Volume

25

Issue

4

First Page

27

Last Page

27

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