Table 3. Summary of studies on the recent advances in the immunohistochemistry of PPGLs.

Authors	Journal	Year	Findings
Papathomas et al. (77)	Modern Pathology	2015	SDHB/SDHA immunohistochemistry reliably identifies patients with SDHx mutations and can be used to evaluate variants of unknown significance for pathogenicity
Menara et al. (78)	Journal of Clinical Endocrinology and Metabolism	2015	SDHD immunostaining can be used to predict or validate SDHx gene variants particularly if there is a weak diffuse SDHB immunostaining
Udager et al. (79)	Human Pathology	2018	Confirmation of the utility of SDHB immunostaining in the identification of SDHx mutations
			First report of FH-deficient immunostaining in a patient with known PGL and FH germline mutation
Farhat et al. (80)	Endocrine Pathology	2019	Identification of CD163 and CD68 positive cells indicative of a monocyte-macrophage lineage in PPGLs
Favier et al. (81)	Modern Pathology	2019	Use of CA9 immunostaining in the identification of VHL mutation

PPGL, pheochromocytomas and paragangliomas.