Pheochromocytoma classification On the Web
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Pheochromocytoma may be classified based on nature of the tumor into benign and malignant. Pheochromocytoma can also be classified based on the spread into local, regional, and metastatic. Another classification based on origin, divides pheochromocytoma into familial, non-familial and sporadic forms.
Classification based on nature of tumor:
- Malignant and benign tumors share the same biochemical and histological characters. The only difference is the ability of the malignant tumor to invade local and distant tissues according to WHO Classification of tumors.
- Most cases need follow up for a long duration.
Classification based on spread:
Classification based on genetics:
- Familial pheochromocytoma is associated with multiple endocrine neoplasia 1 (MEN1) and multiple endocrine neoplasia 2B (MEN2B), which are autosomal dominant syndromes, caused by a mutation in the menin and RET genes, respectively. Pheochromocytoma occurs in 50% of patients with MEN2B.
- The MEN1 and MEN2B syndromes consist of the following features:
- The majority of them are positive for KIT expression, some are not. A partial explanation was provided by the finding of activating mutations in another gene encoding an RTK, the platelet-derived growth factor receptor alpha (PDGFRA) gene in some KIT-negative GISTs:
- Most catecholamine-secreting tumors are sporadic. Mutations have been identified in most of the sporadic cases.
- May be due to spontaneous mutation, decreased penetrance or maternal imprinting.
- 50% of patients had a pathogenic mutation in SDHB, SDHD, or VHL.
- Travis WD, Brambilla E, Nicholson AG, Yatabe Y, Austin JH, Beasley MB; et al. (2015). "The 2015 World Health Organization Classification of Lung Tumors: Impact of Genetic, Clinical and Radiologic Advances Since the 2004 Classification.". J Thorac Oncol. 10 (9): 1243–60. PMID 26291008. doi:10.1097/JTO.0000000000000630.
- Buffet A, Venisse A, Nau V, Roncellin I, Boccio V, Le Pottier N; et al. (2012). "A decade (2001-2010) of genetic testing for pheochromocytoma and paraganglioma.". Horm Metab Res. 44 (5): 359–66. PMID 22517557. doi:10.1055/s-0032-1304594.
- Jafri M, Whitworth J, Rattenberry E, Vialard L, Kilby G, Kumar AV; et al. (2013). "Evaluation of SDHB, SDHD and VHL gene susceptibility testing in the assessment of individuals with non-syndromic phaeochromocytoma, paraganglioma and head and neck paraganglioma.". Clin Endocrinol (Oxf). 78 (6): 898–906. PMID 23072324. doi:10.1111/cen.12074.