Ota Hisashi, Hirokawa Mitsuyoshi, Suzuki Ayana, Oshita Maki, Ito Aki, Fukushima Mitsuhiro, Kobayashi Kaoru, Miyauchi Akira
Kuma Hospital, Department of Clinical Laboratory, Kobe, Japan.
Kuma Hospital, Department of Diagnostic Pathology and Cytology, Kobe, Japan.
Ultrasound Int Open. 2018 Oct;4(4):E119-E123. doi: 10.1055/a-0747-6453. Epub 2018 Oct 19.
The aim of this study was to investigate the ultrasound characteristics and clinical significance of slightly hyperechoic lesions, referred to as phantom nodules, in the perithyroidal area in patients.
A total of 128 patients who underwent thyroidectomy with central neck lymph node dissection at Kuma Hospital in Hyogo, Japan were included in the study. We detected 16 phantom nodules during preoperative ultrasound examinations, defined as slightly hyperechoic masses located in the perithyroidal areas, in 13 of these 128 patients (10.2%; mean age: 55.6 years, range: 36-75 years).
All phantom nodules were located in the caudal region of the thyroid gland, and the mean maximum dimension was 7.2 mm. 12 of the 16 nodules were round or oval, while the remaining 4 were fusiform and molded by the surrounding tissue. All nodules were well-defined, solid, homogeneous, hyperechoic masses. No speckled echo pattern, internal linear echo, or vascular flow signal was observed. All 4 nodules subjected to histological examination were composed of ectopic thymic tissue. In 2 of these 4, the parenchyma was severely involuted and almost entirely replaced by adipose tissue.
To the best of our knowledge, this is the first report wherein some of the detected hyperechoic perithyroidal masses were composed of ectopic thymic tissue, and some were primarily composed of adipose tissue that completely replaced involuted ectopic thymic tissue. The results of the study suggest that these so-called phantom nodules are clinically insignificant and do not require fine needle aspiration cytology or further investigation.
本研究旨在探讨患者甲状腺周围区域内被称为“幻影结节”的略高回声病变的超声特征及临床意义。
本研究纳入了日本兵库县久留米医院128例行甲状腺切除术并同期行中央区颈部淋巴结清扫术的患者。在这128例患者中，有13例（10.2%；平均年龄：55.6岁，范围：36 - 75岁）在术前超声检查中检测到16个幻影结节，定义为位于甲状腺周围区域的略高回声肿块。
所有幻影结节均位于甲状腺尾侧区域，平均最大径为7.2毫米。16个结节中有12个呈圆形或椭圆形，其余4个为梭形且被周围组织塑形。所有结节均边界清晰，为实性、均匀的高回声肿块。未观察到点状回声模式、内部线状回声或血流信号。接受组织学检查的4个结节均由异位胸腺组织构成。其中4个结节中有2个，其实质严重萎缩，几乎完全被脂肪组织替代。
据我们所知，这是首篇报道，其中部分检测到的甲状腺周围高回声肿块由异位胸腺组织构成，部分主要由完全替代萎缩异位胸腺组织的脂肪组织构成。研究结果表明，这些所谓的幻影结节临床意义不大，无需进行细针穿刺细胞学检查或进一步检查。
