Hayama Makio, Yoshitomi Seiji, Tamura Maiko, Ohnishi Nobuhiko, Moriyama Shigeharu
Department of Surgery, Japanese Red Cross Okayama Hospital, 2-1-1 Aoe, Kita-ku, Okayama city, Okayama, 700-8607, Japan.
Department of Pathology, Japanese Red Cross Okayama Hospital, 2-1-1 Aoe, Kita-ku, Okayama city, Okayama, 700-8607, Japan.
Surg Case Rep. 2019 Feb 18;5(1):29. doi: 10.1186/s40792-019-0593-x.
Ectopic hamartomatous thymoma, which usually occurs in the lower neck, is a rare benign tumor containing spindle cells, epithelial nests, and adipose tissue. Although the origin of this tumor is still unknown, recent reports suggest that the designation of this tumor is inappropriate.
A 38-year-old with an anterior cervical mass in the suprasternal region of her neck was referred to our hospital. An ultrasound examination showed that the well-defined oval mass was 31 × 23 × 17 mm in size. A non-enhanced computed tomography scan of the neck revealed that the distinct neck mass in the subcutaneous tissue had a mixture of soft tissue and fatty components. The cervical tumor was clinically diagnosed to be an unusual lipoma with degeneration. The patient underwent the neck mass extirpation. During the surgery, the cervical mass was well demarcated and did not adhere to the surrounding tissues. The postoperative course was uneventful. The gross pathology report showed that the neck mass measured 3.0 × 2.5 × 2.0 cm. Microscopically, the tumor was composed of spindle cells, epithelial nests, and mature adipose tissue. Immunohistochemical examination revealed that both spindle cells and epithelial nests were positive for cytokeratin AE1/AE3. These histopathological findings were consistent with the features of ectopic hamartomatous thymoma. Over a follow-up period of 30 months, this patient exhibited no evidence of recurrence.
Ectopic hamartomatous thymoma should be considered in the differential diagnosis of subcutaneous tumors in the lower neck, when the CT shows the tumor has the mixed components of fat and soft tissues.
异位错构瘤性胸腺瘤通常发生于下颈部，是一种罕见的良性肿瘤，包含梭形细胞、上皮巢和脂肪组织。尽管该肿瘤的起源尚不清楚，但最近的报告表明该肿瘤的命名并不恰当。
一名38岁女性因颈部胸骨上区前方肿物被转诊至我院。超声检查显示，边界清晰的椭圆形肿物大小为31×23×17mm。颈部非增强计算机断层扫描显示，皮下组织中明显的颈部肿物含有软组织和脂肪成分的混合物。该颈部肿瘤临床诊断为退变的不寻常脂肪瘤。患者接受了颈部肿物切除术。手术过程中，颈部肿物边界清晰，未与周围组织粘连。术后恢复顺利。大体病理报告显示，颈部肿物大小为3.0×2.5×2.0cm。显微镜下，肿瘤由梭形细胞、上皮巢和成熟脂肪组织组成。免疫组织化学检查显示，梭形细胞和上皮巢的细胞角蛋白AE1/AE3均呈阳性。这些组织病理学表现与异位错构瘤性胸腺瘤的特征相符。在30个月的随访期内，该患者无复发迹象。
当CT显示肿瘤具有脂肪和软组织混合成分时，在下颈部皮下肿瘤的鉴别诊断中应考虑异位错构瘤性胸腺瘤。
