Thymic carcinoids in multiple endocrine neoplasia type 1.

Thymic carcinoid is a rare malignancy with about 150 cases reported to date. It is associated with multiple endocrine neoplasia type 1 (MEN-1), but compared with other MEN-1-related neoplasia little is known about it. We have recently described and studied 20 MEN-1-related cases and found that up to 25% of all reported thymic carcinoids are MEN-1 related. It is an insidious tumour not associated with Cushing's syndrome or carcinoid syndrome. Local invasion, recurrence and distant metastasis are common with no known effective treatment. Its male predominance, the absence of loss of heterozygosity (LOH) in the MEN1 region, clustering in some MEN-1 families and the findings of different MEN1 mutations in these clustered families suggest the involvement of additional aetiological factors. We propose that computed tomography (CT) or magnetic resonance imaging (MRI) of the chest should be included as part of the clinical workup for all MEN-1 patients. Prophylactic thymectomy should be considered during subtotal or total parathyroidectomy on MEN-1 patients to reduce the risk of this malignancy.