According to WHO, succinate dehydrogenase (SDH)-deficient renal cell carcinoma is characterized by negative immunostaining for SDHB, which remains positive in non-tumor tissue despite germline mutations in the SDHB gene. We now report a patient with a SDHB mutation, c.166_170del (p.Pro56Tyrfs*5) who developed renal cell carcinomas with characteristic morphological features of SDH-deficient renal cell carcinoma but had positive SDHB immunostaining.
Within a 6-year period, the patient developed two different renal cell carcinomas, which had characteristic morphological features of SDH-deficient renal cell carcinoma (uniform cells characteristically displaying eosinophilic granular material intermixed with fewer cells exhibiting clear intracytoplasmic inclusions and bland centered nuclei) but displayed immunohistochemistry for SDHB with a cytoplasmic granular positivity (mitochondrial pattern) in tumor cells. For the second case, this was initially interpreted as positive by IHC, but on review some subtle differences were identified.
SDHB immunostaining may be positive in renal cell carcinoma associated to germline SDHB deficiency which have other typical morphological features. Immunohistochemistry interpretation may be complex.
Diagnostic pathology. 2019 May 15*** epublish ***
Marina Ugarte-Camara, Raul Fernandez-Prado, Isabel Lorda, Gabriela Rossello, Carmen Gonzalez-Enguita, Pablo Cannata-Ortiz, Alberto Ortiz
Nephrology, Hospital Universitario Virgen del Rocio, Sevilla, Spain., Nephrology and Hypertension, IIS-Fundacion Jimenez Diaz UAM and REDINREN, Madrid, Spain. ., Genetics, IIS-Fundacion Jimenez Diaz UAM, Madrid, Spain., Nephrology and Hypertension, IIS-Fundacion Jimenez Diaz UAM and REDINREN, Madrid, Spain., Urology, IIS-Fundacion Jimenez Diaz UAM and REDINREN, Madrid, Spain., Pathology, IIS-Fundacion Jimenez Diaz UAM and REDINREN, Madrid, Spain.