Intrarenal Ectopic Adrenal Cortical Mimicking Renal Cell Tracy R. Shachner DO, Raouf Nakhleh MD Department of Laboratory Medicine and Pathology Mayo Clinic, Jacksonville, FL Introduction Discussion Heterotopic adrenal tissue can be identified in many Most cases of ectopic adrenal tissue are composed of sites, including the abdomen and the tracts of cortical tissue; medullary tissue is uncommon. (2) gonadal descent. (1,2) Adrenal tissue can also be Intra-renal adrenal tissue is often discovered located within the kidney, usually subcapsular. (3) incidentally and is clinically insignificant. Occasionally, ectopic tissue develops into a and can be detected on imaging studies. It is important to be Case Report A B aware of this possibility when considering the differential diagnosis for a solid renal mass. Diagnostic A 68-year-old with abdominal pain underwent a CT Figure 1: Adrenal: Encapsulated lesion ([A] H&E, 40x) made of cytologically bland cells with small nuclei and scan, revealing an incidental 2.4 cm mass in the left vacuolated cytoplasm ([B], H&E, 200x). considerations include clear cell RCC and kidney. The bilateral adrenal and right kidney . In ambiguous cases, were reported as unremarkable. The renal lesion was immunohistochemistry can be utilized. Adrenal suspicious for (RCC) and the cortical will show reactivity with inhibin and patient underwent partial nephrectomy. Melan-A, whereas RCC will show reactivity with Intraoperatively, the renal lesion was adherent to a left epithelial markers. Compared to cortical adenomas, adrenal lesion. The adrenal was freely mobilized, more commonly demonstrate and the lesion was resected. The partial nephrectomy increased/atypical mitoses, larger size, and necrosis. was completed without complications. Gross A B examination demonstrated a 3.0 cm orange mass Figure 2: Kidney: Unencapsulated lesion ([A] H&E, 20x) made of cytologically bland cells with small nuclei and within the and a second 3.0 cm orange vacuolated cytoplasm ([B], H&E, 200x), consistent with adrenal tissue. mass in the kidney. Microscopically, the adrenal lesion (Figures 1 and 3A) showed an encapsulated lesion composed of cells with References vacuolated cytoplasm, consistent with cortical 1) Goldblum JR, Lamps LW, McKenny J, et al, eds. Rosai and Ackerman’s Surgical Pathology. 11th ed. Cambridge, MA: Elsevier, 2018 adenoma. The renal lesion was unencapsulated, with 2) Ye H, Yoon GS, Epstein JI. Intrarenal ectopic adrenal tissue and renal-adrenal cytologic features identical to those seen in the fusion: a report of nine cases. Mod Pathol. 2009 Feb;22(2):175-81. doi: 10.1038/modpathol.2008.162. Epub 2008 Sep 26. PMID: 18820668. adrenal lesion (Figures 2 and 3B). 3) Liu Y, Jiang YF, Wang YL, et al. Ectopic in the renal hilum: a case report and literature review. Diagn Pathol. 2016;11:40. Published 2016 Apr 19. doi:10.1186/s13000-016-0490-6 A B Figure 3: Side by side comparison of the adrenal lesion ([A] H&E, 400x) and renal lesion ([B], H&E, 400x), highlighting the identical nuclear and cytoplasmic features.