Loss of heterozygosity studies indicate that retinal hamartoma is a true component of neurofibromatosis (NF) type 2 and pheochromocytoma a true component of NF type 1 (1). A retrospective cohort study of NF type 1 patients from the Mayo Clinic found the age at presentation to be between age 14 years and 70 years with a pheochromocytoma size between 8 mm and 9.5 cm. In that series, metastatic or recurrent disease occurred in 7.3% of patients. Metastatic adrenal pheochromocytoma in NF1 can present at a size of 2.5 cm at the age of 17 years (2).
The American College of Medical Genetics and Genomics (ACMG) guidelines recommend considering pheochromocytoma in hypertensive NF1 patients age older than age 30 y and do not recommend biochemical or imaging screening in asymptomatic patients.
The authors of the Mayo Clinic study recommend biochemical case detection for pheochromocytoma every 3 years starting at age 10 y and also before elective surgical procedures and conception. In analogy, the screening for pheochromocytoma in patients with von Hippel Lindau disease is recommended at age 4 years, considering that there also are “asymptomatic” individuals with malignant disease (3).
References
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