39例中老年重症肌无力患者淋巴样滤泡性胸腺增生的CT表现

CT apperances of lymphoid follicular hyperplasica of thymus in middle aged and elderly patients with myasthenia gravis

目的探讨中老年重症肌无力患者淋巴样滤泡性胸腺增生的发生情况和CT表现. 方法对39例经手术病理确诊为淋巴样滤泡性胸腺增生的中老年重症肌无力患者作了影像学分析,并与健康中老年人、青年重症肌无力患者淋巴样滤泡性胸腺增生作对比分析.凡无胸腺区形态正常的软组织影、无胸腺区脂肪内边缘清楚的肿块(>3 cm)或结节(<3 cm)和边缘模糊的斑片影者视为不典型淋巴样滤泡性胸腺增生. 结果 31例(79.5%)呈不典型表现,全部表现为胸腺区脂肪内夹杂＜5 mm的斑点和细索条影;与健康中老年人和青年重症肌无力患者比较差异均有统计学意义(分别为χ2=4.135,P＜0.05;χ2=9.584,P＜0.01).其中1级7例, 2级14例, 3级8例, 4级2例,1～3级与健康中老年人比较,差异有统计学意义(P＜0.01).仅8例(20.5%)呈典型表现, 包括胸腺区结节2例、胸腺软组织影2例和胸腺区边缘模糊的斑片致密影4例. 结论大多数中老年重症肌无力患者淋巴样滤泡性胸腺增生的CT表现不典型,以男性多见,容易漏诊.

Objective To study the CT apperances of lymphoid follicular hyperplasica of thymus in middle aged and elderly patients with myasthenia gravis. Methods Thirty-nine myasthenia gravis （MG）patients with lymphoid follicular hyperplasica of thymus in middle aged and elderly proven by pathology were evaluated by CT and/or enhanced CT scan. Results Thirty-one（79.5 %） cases had atypical findings of lymphoid follicular hyperplasica of thymus at presentation. The atypical appearances on CT were thymic spots and/or fine lines, and had difference （P〈0.05）compared with the findings of the normal middle aged and elderly, including type 1 （7 cases）, type 2 （14 cases） , type 3 （8 cases） and type 4 （2 cases） . Only 8 （20.5%） cases had typical findings of lymphoid follicular hyperplasica of thymus on CT, include 2 cases with thymic nodules（〈3 cm）,2 cases with thymic soft-tissue density and 4 cases with mottling（〉5 mm）. Conclusions The most patients with lymphoid follicular hyperplasica of thymus in the middle aged and elderly MG have atypical CT appearances. It frequently occurs in men, and the diagnosis is easily mistaken on CT scan.