Department of Thoracic Surgery, Chigasaki Municipal Hospital, Honson 5-15-1, Chigasaki, Kanagawa 253-0042, Japan.
Tokai J Exp Clin Med. 2021 Jul 20;46(2):94-96.
Micronodular thymoma with lymphoid stroma (MNT) is a rare subtype of thymic neoplasms. Therefore, clinical guidelines, histopathological diagnostic criteria, prognostic factors, and therapeutic regimens have not been established.
A 69-year-old woman was admitted to our hospital because of an abnormal shadow detected by chest radiography. Further imaging revealed an anterior mediastinal tumor measuring 65×28×15 mm. We performed thymectomy for diagnosis and treatment. Histopathological examination revealed spindle cells comprised multiple micronodules separated by abundant interstitial lymphocytes and lymphoid follicles. Immunohistochemical staining showed that the tumor was positive for cell adhesion molecule (CAM), cytokeratin (CK) 5/6, and terminal deoxynucleotidyl transferase. The histopathological diagnosis was MNT and the stage was I by the World Health Organization classification. The patient remained free of recurrence for seven years after surgery.
When the lesion is completely resected, MNT has a good prognosis. Therefore, MNT is considered to be a borderline tumor with good prognosis and no reports of recurrences, distant metastasis, or tumor-related deaths exist thus far. However, preoperative diagnosis is difficult in most cases. Hence, complete surgical resection is recommended for suspicious mediastinal masses, if feasible, for both accurate diagnosis and to ensure long-term survival.
伴淋巴间质的微结节性胸腺瘤（MNT）是一种罕见的胸腺肿瘤亚型。因此，尚未制定临床指南、组织病理学诊断标准、预后因素和治疗方案。
一名 69 岁女性因胸部 X 线检查发现异常阴影而入院。进一步的影像学检查显示前纵隔肿瘤大小为 65×28×15mm。我们进行了胸腺切除术以明确诊断和治疗。组织病理学检查显示，肿瘤由多个微结节组成，微结节之间有丰富的间质淋巴细胞和淋巴滤泡分隔。免疫组织化学染色显示肿瘤细胞黏附分子（CAM）、细胞角蛋白（CK）5/6 和末端脱氧核苷酸转移酶阳性。组织病理学诊断为 MNT，世界卫生组织（WHO）分类为 I 期。术后 7 年，患者无复发。
当病变完全切除时，MNT 预后良好。因此，MNT 被认为是一种具有良好预后的交界性肿瘤，迄今为止尚无复发、远处转移或肿瘤相关死亡的报道。然而，大多数情况下术前诊断较为困难。因此，如果可行，建议对可疑的纵隔肿块进行完全手术切除，以便准确诊断和确保长期生存。
