The Prostate is a Common Site of Disease in Patients with MEN2B and Medullary Thyroid Carcinoma.

We reviewed the clinical characteristics of male patients with MEN2B associated medullary thyroid cancer (MTC) with prostate lesions and analyzed available imaging and pathology data.Patients were enrolled on a National Cancer Institute (NCI) natural history protocol (NCT01660984) and a University of Texas (UT) MD Anderson Cancer Center study (DR09-0507).Thirty-six male patients (median age of MEN2B diagnosis 12.0 years, range 1.3-25.6) with the RET p.Met918Thr germline mutation were identified.Pelvic imaging was available for 28/36 (78%) patients. Prostate lesions and/or calcifications were noted in eight patients (28.6%). Lesions were identified at a median age of 20.5 years (range 13-30.5 years). Biopsies in three patients with prostate neoplasms were histologically indistinguishable from primary MTC. Two of these patients did not have other sites of distant disease at the time of prostate biopsy. Prostate lesions in males with MEN2B and MTC are more frequent than previously described. Lesions were identified in patients as young as 14 years and often contained calcifications. The prostate is a more common site of disease in patients with MEN2B than previously appreciated and may represent a distant site of metastatic MTC metastasis or a second primary calcitonin-secreting neuroendocrine tumor. Imaging of the prostate should be considered in post-pubertal MEN2B males, especially in case of unexplained increase in calcitonin or onset of urinary tract symptoms.