Endocrine Abstracts

Introduction: Medullary thyroid carcinoma MTC represents 5% of all thyroid cancers. It is familial in 30% of the cases. The most frequent metastatic localizations are lymph nodes, liver, lung and bone. We describe prostatic and vesical localizations of a MTC in a patient with multiple endocrine neoplasia (MEN 2B).

Case report: A 44 years old patient with MEN 2B operated in 1989 for MTC, bilateral pheochromocytoma and had a cutanuous neurofibroma. He presented with persistent dysuria and abdominopelvic pain with testicular irradiation. Computed tomography detected a heterogeneously enlarged prostate and another mass at left uretero-vesical junction. Histopathological study after a radical operation in 2009 confirms the existence of a neuroendocrine tumor (NET) with positive immunostaining to chromogranin A, synaptophysine and calcitonine. Re-analysis of the two lesions with the previous thyroid slides confirms the identity of a MTC with its metastatic lesions. Serum calcitonin declined postoperatively from 233 to 65 pg/ml.

Discussion and conclusion: Few metastatic localizations of NET in the prostate are described. Calcitonin positive prostatic tumor is reported in the literature. It might be an indicative of either a MTC or a NET, as calcitonin immunostaining is possible in a normal endocrine tissue of the prostate. Bladder localizations are never documented. Absence of a primary NET, bladder localization devoid of prostatic tissue and improvement of elevated calcitonin levels in our patient make us to consider these localizations as metastatic lesions of MTC rather than a NET of prostate.

Elevated neuroendocrine markers with unexplained chronic urinary tract symptoms and/or a prostatic tumor in young patients in the context of a NET should evoke a NE localization. Neuroendocrine immunohisochemical staining should be done to line out the management of these rare tumors, as the prognosis of a MTC, primary prostatic adenocarcinoma or a NET is not identical.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector