Medullary Thyroid Carcinoma and Papillary Thyroid Carcinoma in the Same Patient as a Collision Tumour

Case Reports in Endocrinology
19 Apr, 2019 ,

A 35-year-old patient was admitted to endocrinology outpatient department with complaint of pain in the neck. Physical examination revealed 2 cm nodule on the thyroid right lobe. Serum thyroid hormone levels were within normal range. Ultrasonography revealed a 23x15 mm hypoechoic nodule with micro calcifications and cystic areas on the right lobe. 

Full content

A 35 years old patient has been admitted to endocrinology outpatient department with the complaint of pain in the neck radiating to ears. Physical examination revealed 2 cm nodule on right lobe of the thyroid. She has no personal history of radiation exposure and family history of thyroid cancer. Serum levels of free triiodothyronine and free thyroxine were within normal ranges. Serum calcitonin level was 2 pg/ml (0-11.5) (postsurgical measurement). Antithyroglobulin antibody (anti-Tg Ab) was negative. A preoperative thyrotropin serum value was suppressed (0.129 μU/ml).

Thyroid ultrasonography revealed 23 mm hypoechoic nodule with microcalcifications and cystic areas on the right lobe. No pathological lymph node was detected on ultrasonography. Magnetic resonance imaging of the neck revealed no lymph node on the jugular region. Fine needle aspiration biopsy from the thyroid nodule was performed. Prominent polychromasia, overlapping on thyrocytes, and occasional bizarre nuclei were detected on cytology. Primarily it was thought papillary carcinoma of thyroid. Bilateral total thyroidectomy was performed. On pathological examination there were two tumours on the right lobe. These are PTC with 1.7 cm in diameter and MTC with 1.8 cm in diameter. Amyloid-like material accumulation and hemorrhagic stroma were detected on MTC.

 Also spindle cells with bizarre nuclear structure covered with capsule with local fibrotic areas were seen on pathologic evaluation. Chromogranin A and calcitonin was positive on immunohistochemical staining which was compatible with MTC.

 Necrosis, lymphovascular invasion, calcification, and capsular involvement of tumour were not detected in PTC. Papillary component had a capsule. On the light microscopy papillary structures with thyrocytes having nuclear clearing, grooving, and overlapping around fibrovascular core were detected.

 Remaining thyroid was compatible with lymphocytic thyroiditis. RET gene analysis revealed no MEN 2 related mutation in this patient. She received radio-ablative treatment with I131sixth month later following surgery. She is under suppressive treatment with levothyroxine sodium. She has been followed up without any evidence of disease since then.