Abstract
Background: Multiple endocrine neoplasia type 2 is an autosomal dominant disorder with an estimated prevalence of 1 per 30,000 in the general population. Classical multiple endocrine neoplasia 2A is the most common variant. It is a heritable predisposition to medullary thyroid cancer, pheochromocytoma, and primary parathyroid hyperplasia. The respective frequency of these tumors in classical MEN2A is over 90 percent for MTC, approximately 10 to 50 percent for pheochromocytoma, and 10 to 20 percent for multigland parathyroid hyperplasia.
Discussion: our interesting patient is a 67-year-old patient with past medical history of prophylactic total thyroidectomy at the age of 25 years after a positive pentagastrin test (sister was diagnosed with MTC, pheochromocytoma),niece with metastatic kidney cancer.at that time, patient had benign pathology. Patient presented to the ED with a complain of shortness of breath after being referred by her PCP for evaluation of possible pneumonia. In the ED, her vitals were within normal, chest X-ray was done and didn’t show pneumonia but the patient was found to have elevated procalcitonin of 22.7 ng/mL(0.09 ng/mL) CT chest was done and showed enlarged necrotic cervical lymphadenopathy which was confirmed by obtaining CT of the neck. Patient had right cervical LN core biopsy, pathology was positive for medullary thyroid cancer with Immunohistochemical studies positive for TTF-1, chromogranin, synaptophysin and calcitonin, testing for pheochromocytoma came back within normal, CEA 70.7ng/ml (<0.25 ng/ml), calcitonin 2949 pg/ml (5 pg/mL) Chromogranin was high at 453 ng/ml (25 - 140 ng/mL) had PET CT with multiple low right cervical and supraclavicular lymph nodes with internal calcifications and abnormal FDG activity, which were suspicious for medullary thyroid cancer metastases, she eventually had radical neck dissection with pathology from inferior parathyroid gland positive for medullary thyroid cancer and 12/15 regional LN positive for malignancy, after the procedure her calcitonin dropped nicely to 194pg/ml, CEA dropped to 4.0, chromogrannin to 394, she was referred to genetic testing and tested positive for pathogenic variant within RET (c.1859G>T, p.Cys620Phe), which is known to be associated with multiple endocrine neoplasia type 2A, she is currently being evaluated for Lutathera treatment.
Conclusion: In contrast to MEN1, in which the long-term benefit of early diagnosis by genetic screening is not well established, early diagnosis by screening of “at-risk” family members in MEN2 with positive RET mutation kindreds is essential because MTC is a life-threatening disease that can be cured or prevented by early thyroidectomy. Total thyroidectomy has been recommended for patients as young as 3 years for MEN2A if they contain the genetic mutation.
Metastatic Thyroid Cancer After Thyroidectomy in Patient With Neuroendocrinal Tumor
