2019-21 / JULY 8

25-year-old white male presents with large renal mass with pulmonary metastases. A nephrectomy was performed. SDH B immunostain is shown.


1. What testing is appropriate for this patient?

a. Germline testing for SDH B mutation

b. Germline testing for fumarate hydratase mutation

c. Mismatch repair enzyme immunohistochemical stains on tumor tissue

d. PD-L1 immunohistochemical stain on tumor tissue


2. What other tumors might this patient have?

a. Colonic adenocarcinoma

b. Extra-adrenal paraganglioma

c. Pancreatic islet cell tumor

d. B cell lymphoma


3. What of the following features is not a prognostic features in this tumor?

a. WHO/ISUP grade

b. Sarcomatoid features

c. Coagulative tumor necrosis

d. Presence of a synchronous paraganglioma

1. a
2. b
3. d

1. Germline testing for SDH B mutation
2. Extra-adrenal paraganglioma
3. Presence of a synchronous paraganglioma

Succinate dehydrogenase deficient renal cell carcinoma is a rare subtype of inherited renal cell carcinoma that is tied to germline mutations in one of the SDH genes, most commonly SDH B. The SDH genes encode for proteins that form the mitochondrial complex II that is involved in the citric acid cycle and electron transport chain and catalyze succinate to fumarate with the reduction of ubiquinone to ubiquinol. Mutations in these genes are also referred to as “Mitochondrial Complex II deficiencies”, and biallelic loss of these genes is associated with significant abnormalities. Renal tumors arise in young patients, and these tumors are typically associated with indolent behavior and excellent outcome following excision. Infrequently (approximately 10% of cases), tumors may act aggressively, and features that predict aggressive behavior include high grade, coagulative tumor necrosis and sarcomatoid and rhabdoid features. This patient had a germline mutation in SDH B.

Succinate dehydrogenase (SDH)-deficient renal carcinoma: a morphologically distinct entity: a clinicopathologic series of 36 tumors from 27 patients. Gill AJ, Hes O, Papathomas T, et al.
Am J Surg Pathol 2014;38:1588-602.

John Cheville
Mayo Clinic, Rochester


SDH B, renal cell carcinoma, high-grade