Multiple endocrine neoplasia type 1 laboratory findings

{{}} Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Ammu Susheela, M.D. [2]

Overview

==Laboratory Findings? Laboratory tests may be performed periodically to screen for MEN1 tumors. Screening can catch tumors in their early stages of development, detect tumors that have come back, and indicate how large they are and where they are located. Catching tumor development early allows doctors to take steps to prevent serious complications from occurring in people with MEN1. Types of tests used for tumor screening can include

blood tests-for example, to measure insulin or PTH to detect excess hormone production by a MEN1 tumor. other biochemical tests-for example, to measure urinary calcium to detect the results of excess hormone production. immunoradiometric assays, a type of blood test-for example, to measure PTH to detect parathyroid tumors. imaging tests-for example, ultrasound, computerized tomography (CT), and magnetic resonance imaging (MRI) to allow the doctor to detect tumors that are not secreting hormones. Because imaging tests are more expensive, they are typically done less often than blood tests.

The types of tests performed depend on the purpose of the screening. Periodic screening for MEN1 tumors can have two different purposes:

To recognize possible carriers of MEN1. First, screening may be performed to determine if an individual is a carrier of the MEN1 mutation. This screening includes close relatives of a person known to carry MEN1. Although gene testing is one way to identify a carrier of MEN1, sometimes these other methods are used due to a lack of resources, or when the underlying mutation cannot be identified. For this screening purpose, tests are directed at tumors that are most frequent and develop the earliest. Examples of these tests include PTH, calcium, and prolactin tests. To detect early tumors in known carriers of MEN1. Second, screening may be performed in known carriers ofMEN1 to look for any tumor that could develop as a result of the mutation. This periodic testing can recognize a tumor early to optimize its treatment. When an individual is a known carrier of MEN1, more detailed testing is performed to screen for some of the less likely but still harmful tumors.

Laboratory tests for MEN1 tumors can be repeated yearly without waiting for symptoms to appear. This testing can begin at age 5. In known carriers, imaging tests may be performed every 3 years to locate tumors that cannot be found with other laboratory testing.

If an individual's tests are normal, periodic tumor testing should continue indefinitely. However, an unproven carrier with normal tests beyond age 50 is unlikely to have inherited a MEN1 gene mutation.