Intratumour heterogeneity in a BRAV600E-mutated papillary thyroid carcinoma. Intratumour heterogeneity in a BRAV600E-mutated papillary thyroid carcinoma

A 51 year old female was diagnosed with a bilateral PTC (right lobe: 0,6 cm; left lobe: 2,8cm) with concurrent metastatic involvement of the lymph nodes. This corresponded to a stage IVA PTC (pT3N1b). She was treated with a total thyroidectomy and a lymphadenectomy, with 5 nodal metastases in the recurrent and mediastinal areas. Iodine-131 radiotherapy was administered one month after surgery. Twelve months after thyroidectomy, she was operated for nodal recurrences (4 nodal metastases from the left cervical, 3 of which were included in the study, annotated M2, M3 and M4). Histopathological examination revealed a classical PTC developing in a goiter context, and suggested a tumour cell fraction greater than 70%. Exome were sequenced for 4 blocks of the left-lobe tumour, 1 block of the right-lobe tumour, the 3 nodal metastases, 2 normal lymh nodes, 3 blocks of normal adjacent thyroid, and 1 blood sample.

一例51岁女性被诊断为双侧乳头状甲状腺癌（Papillary Thyroid Carcinoma, PTC），其中右叶病灶大小为0.6 cm，左叶病灶大小为2.8 cm，同时伴淋巴结转移，临床分期为IVA期PTC（pT3N1b）。患者接受了全甲状腺切除术及淋巴结清扫术，于复发区域及纵隔区检出5枚淋巴结转移灶。术后1个月予以碘-131放疗。甲状腺切除术后12个月，患者因淋巴结复发再次接受手术：术中发现左侧颈部存在4枚淋巴结转移灶，其中3枚纳入本研究，分别标注为M2、M3和M4。组织病理学检查显示，该肿瘤为伴甲状腺肿背景的经典型PTC，肿瘤细胞占比超过70%。本研究对以下样本进行了外显子组测序：左叶肿瘤4个测序区块、右叶肿瘤1个测序区块、3枚淋巴结转移灶、2枚正常淋巴结、3块癌旁正常甲状腺组织，以及1份血液样本。