A 51/2-year-old boy, with a family history of multiple endocrine neoplasia (MEN)-2A syndrome, was evaluated for presence of MEN-2A and medullary thyroid carcinoma (MTC). DNA diagnostics confirmed MEN-2A. Basal (360 ng/L) and pentagastrin stimulated (430 ng/L) calcitonin (CT) levels were slightly elevated, plasma carcinoembryonic antigen (CEA) was normal. Within a year both tumor markers increased and total thyroidectomy was performed. Histologic examination did not show MTC. In the following years, both tumor markers increased progressively but despite the use of multiple imaging techniques no metastases were localized. After 6 years, biopsy of a palpable lymph node showed MTC. The boy was treated with total cervical, suprahyoidal, and mediastinal lymph node dissection, showing MTC in almost all nodes. Again, the tumor markers remained high. At this point in time, the disadvantages of further medical interventions were outweighed against the chance for cure and it was decided to shift the goal of treatment toward palliation rather than cure. At the last visit the boy was clinically well with persistent extremely high levels of plasma CEA and CT. In conclusion, when prophylactic thyroidectomy in the MEN-2A syndrome has failed, it may be best to withdraw from further interventions to prevent more damage.