“Incidental” Medullary Carcinoma


Question

I have a patient who was operated for a benign goiter (colloid) -age 49-Mother had papillary thyroid cancer-My patient had total thyroidectomy -a 6 mm left lobe only medullary cancer was found in the specimen when the analysis was completed-

My questions are 1. What do we know about the behavior of incidental medullary cancers?- T his lesion was not seen on US prior to surgery and was not the reason she went for surgery (it was total gland size with some increasing awareness with swallowing 2. This patient did not undergo central lymph node dissection at the time of original surgery . -I told the surgeon that I did n o t think she should go back for re-operation-Am I correct with this? 3. How do we follow this patient beyond exams, calcitonin (and maybe CEA), and perhaps periodic ultrasounds- Any role for genetic screening? Thanks as always Jeffrey Sanfield, M.D-Ann Arbor Endocrinolgy , -Sanfielj@Trinity-Health.org

Response

Dear Dr. Sanfield, Y our patient has an incidental microMTC detected at histology. Not very much is know about the natural history of microMTC. except that by screening thyroid nodules by calcitonin measurement we are discovering more and more cases like this. From the practical point of view what I will suggest is to measure calcitonin in basal condition and after pentagastrin stimulation. After total thyroidectomy calcitonin should be undetectable both basal and l ater stimulation. If this is the case, and I strongly believe that it is, the patient may be considered in complete and probably permanent remission and does not need any further test or therapy. If calcitonin is still detectable it means that some parafollicular C cells are still present in the thyroid residue (if any) or in some lymph node of the neck and in this case the follow-up should try to identify the source of calcitonin production. Sincerely , F. Pacini MD