CALCITONIN NEGATIVE MEDULLARY THYROID CANCER - IMPORTANCE OF MONITORING THE PATIENTS WITH THYROID NODULES IN TIMELY DIAGNOSIS AND TREATMENT: A CASE REPORT

Abstract

The main types of thyroid cancer are follicular, papillary, anaplastic and medullary. Medullary carcinoma is a rarest of them, that originates from the malignant proliferation of parafollicular C cells. The most of them are associated with high levels of calcitonin and carcinoembryonic acid (CEA). Calcitonin-negative medullary carcinoma of the thyroid is an extremely rare entity that is characterized by classic medullary carcinoma of the thyroid morphology without raised serum calcitonin levels. Fine needle biopsy (FNAB)is a diagnostic test done in people with suspected thyroid cancer and it is very important fortimely diagnosis and treatment of medullar thyroid cancer, especially when calcitonin and CEA levels are in normal levels. Case presentation: A 35-yearold woman visited an endocrinologist due to swelling on the left side of the neck. Thyroid ultrasound showed hypoechogenic, heterogenic nodule in the left lobe with dimensions 29x28x35mmand calcifications. Laboratory tests were normal: TSH 3,0 mlU/ml; fT4 14,3 pmol/l; ATPO 20IU/ml; Human thyroglobulin 35IU/ml; Calcitonin 4,5pg/ml; CEA 0.742ng/ml. The FNAB were performed,with cytological finding for Classification group I. Four months after tne FNAB was repeatedand Hürthlecells were found, cytological founding for classification group III. CT of the neck were performed preoperatively and it showed hypodense nodule (slightly smaller than 4 cm) with numerous calcifications, and no significantly lymph nodes enlarged.Left lobectomy was performed with histopathological findings for Medullar thyroid carcinoma. Immunohistochemical tumor cells were positive for Chromogranin A, CD56, focally for Thyroglobulin and CK 19, and negative for S-100 and NSE.Conclusion: Calcitonin normal levels doesn’t exclude medullar carcinoma. Follow-up and monitoring of the patients with thyroid nodules is very importantfor timely diagnosied and treatment of medullar carcinoma.