Dikbas Oguz, Duman Aslihan Alpaslan, Guvendi Gulname Findik
Giresun University School of Medicine, Department of Internal Medicine, Turkey.
Giresun University School of Medicine, Department of Pathology, Turkey.
Case Rep Endocrinol. 2019 Mar 12;2019:4038628. doi: 10.1155/2019/4038628. eCollection 2019.
Papillary thyroid carcinoma (PTC) and medullary thyroid carcinoma (MTC) are two different types of thyroid carcinoma with significant different clinical and histological findings. Their coexistence in the same patient is a very rare event which demands different clinical approach.
We report a case with concurrent MTC and PTC in the same thyroid having characteristics of a collision tumour. A 35-year-old patient has 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. Preoperative serum calcitonin was 2 pg/ml (0-11.5). PTK 1.7 cm and MTK 1.8 cm in the same thyroid with healthy tissue in between them were detected on pathological examination. RET gene mutation was negative. She has been followed up to now without any evidence of disease.
This is a collision tumour since lesions with features of MTC and PTC were detected in two different locations and separated by normal thyroid tissue. Germline point mutation of the RET gene had a potential role in the development of both MTC and PTC. On the other side, familial concurrent MTC and PTC without RET gene mutation was also published. Both RET and BRAF genes had a role in the development of the medullary and papillary collision tumours. We do not know the presence of BRAF gene mutation in this case report yet.
甲状腺乳头状癌（PTC）和甲状腺髓样癌（MTC）是两种不同类型的甲状腺癌，具有显著不同的临床和组织学表现。它们在同一患者中共存是非常罕见的情况，需要不同的临床处理方法。
我们报告一例同一甲状腺内同时存在MTC和PTC的病例，具有碰撞瘤的特征。一名35岁患者因颈部疼痛就诊于内分泌门诊。体格检查发现甲状腺右叶有一个2厘米的结节。血清甲状腺激素水平在正常范围内。超声检查显示右叶有一个23×15毫米的低回声结节，伴有微钙化和囊性区域。术前血清降钙素为2皮克/毫升（0 - 11.5）。病理检查在同一甲状腺内检测到PTC为1.7厘米，MTC为1.8厘米，两者之间有健康组织。RET基因突变阴性。到目前为止，她一直在接受随访，没有任何疾病迹象。
这是一个碰撞瘤，因为在两个不同位置检测到具有MTC和PTC特征的病变，且被正常甲状腺组织分隔。RET基因的种系点突变在MTC和PTC的发生中可能起作用。另一方面，也有关于无RET基因突变的家族性MTC和PTC并存的报道。RET和BRAF基因在髓样和乳头状碰撞瘤的发生中都起作用。在本病例报告中，我们尚不知道BRAF基因突变的情况。
