Endocrine Connections (Nov 2021)
Metastatic cluster 2-related pheochromocytoma/paraganglioma: a single-center experience and systematic review
Abstract
Risk of metastatic disease in the cluster 2-related pheochromocytoma/paraganglioma (PPGL) is low. In MEN2 patients, identification of origin of met astases from pheochromocytoma (PCC) or medullary thyroid carcinoma (MTC) is challenging as both are of neuroendocrine origin. We aim to describe our experience and perform a systematic review to assess prevalence, demographics, biochemistry, diagnostic evaluation, management, and predictors of cluster 2-related metastatic PPGL. Retrospective analysis of 3 cases from our cohort and 43 cases from world literature was done. For calculation of prevalence, all reported patients (n = 3063) of cluster 2 were included. We found that the risk of metastasis in cluster 2-related PPGL was 2.6% (2% i n RET, 5% in NF1, 4.8% in TMEM127 and 16.7% in MAX variation). In metastatic PCC in MEN2, median age was 39 years, bilateral tumors were present in 71% and median tumor si ze was 9.7 cm (range 4–19) with 43.5% mortality. All patients had a primary tumor si ze ≥4 cm. Origin of primary tumor was diagnosed by histopathology of metastatic lesion in 1 1 (57.9%), 131I-MIBG scan in 6 (31.6%), and selective venous sampling and CT in 1 (5.3%) patient each. In subgroup of neurofibromatosis 1 (NF1), median age was 46 years (range 14– 59) with median tumor size 6 cm and 57% mortality. To conclude, the risk of metastati c disease in cluster 2-related PPGL is low, being especially high in tumors with size ≥4 cm and associated with high mortality. One-third patients of NF1 with metastatic PPGL had presented in second decade of life. Long-term studies are needed to formulate management recommendations.
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