甲狀腺腫瘤 - 醫生

家父前些日子作健康檢查發現甲狀腺腫瘤，今天去醫院檢查拿了份報告回來，醫生建議腫瘤太大需要開刀切除，報告內容如下。查了一下字典應該不是惡性腫瘤？想再請醫生幫忙告知詳盡的報告內容，另外開刀是否有甚麼危險，還有其他注意事項及建議，謝謝了！！
Echo:
R’t lobe: 2.68 x 1.83 x >3.7 cm
L’t lobe: 3.18 x 2.65 x > 3.7 cm
A heterogenous iso-hyopechoic nodule (1.11 x 0.76 x 1.19 cm) is located at
upper poriton of left lobe. A cyst (0.51 x 0.36 x 0.35 cm) is located in the
upper portion of left lobe. An ill-defined heterogenous isoechoic nodule
(2.99x3.04x3.78 cm) with cystic changes and microcalcification occupied
almost the middle and the lower portion of right lobe.
Aspiration:
Two times from right nodule via 25G neddle
Cytology
Some clusters of follicular cells with mild anisonucleosis and slightly
coarse chromatin, some are of pyknotic changes.
Diagnosis
Multinodular goiter with cystic changes and microcalcification
Suggest
Surgical treatment due to huge mass or follow up