Succinate dehydrogenase deficient renal cell carcinoma frequently expresses GATA3 and L1CAM

Succinate dehydrogenase deficient renal cell carcinoma (SDH RCC) is an uncommon, familial RCC that has overlapping morphologic features with other low grade eosinophilic tumors of the kidney. Although the diagnosis of SDH RCC relies on loss of SDHB by immunohistochemistry (IHC), not all laboratories have access to this antibody. GATA3 and L1CAM are increasingly utilized in the diagnosis of eosinophilic renal tumors; however, their expression profile has not been studied in SDH RCC. We evaluated clinical parameters and GATA3 and L1CAM reactivity in a large nephrectomy cohort (n = 40) of patients with SDH RCC. The male-to-female ratio was 3:1 and the median age was 48 years (range: 17 to 79 years). Specimens included 20 radical resections, 19 partial resections, and 1 unknown procedure. Tumor laterality was nearly equal (right:left = 18:20; one case was bilateral). Tumors in 4 (10%) patients were multifocal. Median tumor size was 2.0 cm (range 1 – 14.8 cm). Tumor stage distribution was: pT1a (n = 16, 40%), pT1b (n = 7, 18%), pT2a (n = 5, 13%), pT2b (n = 4, 10%), pT3a (n = 6, 15%), and pT4 (n = 1, 3%). Most cases (n = 33, 83%) exhibited classical morphologic features, whereas 2/40 (5%) had sarcomatoid differentiation. GATA3 was positive in 37/39 (95%) tumors, with more than 50% of cells positive in 35/37 (95%), and with moderate-high intensity (2/3 +) in 33/37 (89%). L1CAM was expressed in 13/18 (72%) tumors, with moderate-high intensity (2/3 +) in 10/13 (77%). When both markers were performed, dual GATA3/L1CAM expression was present in 12/17 (71%) tumors. As L1CAM has been postulated to represent a marker of principal cell of the distal nephron, frequent L1CAM expression in SDH RCC suggests that they may originate from the principal cells of the distal nephron.