Bangerter M, Behnisch W, Griesshammer M
Department of Medicine III, University of Ulm, Germany.
Acta Cytol. 2000 Sep-Oct;44(5):743-7. doi: 10.1159/000328555.
Thymic hyperplasia in the anterior mediastinum can occur in healthy children as idiopathic thymic hyperplasia or as a rebound effect after administration of chemotherapy in patients with malignancies. Thymic hyperplasia after chemotherapy is a well-documented phenomenon, particularly in children and less frequently in adults. Both forms of thymic hyperplasia are a diagnostic challenge, and most patients undergo surgical exploration. Fine needle aspiration cytology (FNAC) has supposed to be inadequate to diagnose benign thymic hyperplasia and to separate it from malignant disease.
We report the cytologic findings on eight patients presenting with a mass in the anterior mediastinum that was diagnosed as thymic hyperplasia on FNAC. In five patients the masses developed after chemotherapy. The remaining three patients were healthy children. Three patients underwent ultrasound-guided aspiration; in five cases the procedure was performed under computerized guidance.
In all eight patients the cytologic smears showed a mixed population of lymphoid cells. Cytologic diagnosis of thymic hyperplasia was confirmed by immunophenotyping in three patients and by follow-up studies in all of them (median, 68 months; range, 8-113).
In contrast to previous reports, this study demonstrated the utility of FNAC as a front-line investigative procedure in diagnosing thymic hyperplasia.
前纵隔胸腺增生可发生于健康儿童，表现为特发性胸腺增生，也可发生于恶性肿瘤患者化疗后的反弹效应。化疗后胸腺增生是一种有充分文献记载的现象，尤其在儿童中常见，在成人中较少见。这两种形式的胸腺增生均是诊断难题，大多数患者需接受手术探查。细针穿刺细胞学检查（FNAC）据认为不足以诊断良性胸腺增生并将其与恶性疾病区分开来。
我们报告了8例前纵隔肿块患者的细胞学检查结果，这些患者经FNAC诊断为胸腺增生。其中5例患者的肿块在化疗后出现。其余3例患者为健康儿童。3例患者接受了超声引导下穿刺；5例在计算机引导下进行了该操作。
所有8例患者的细胞学涂片均显示淋巴细胞混合群体。3例患者通过免疫表型分析证实了胸腺增生的细胞学诊断，所有患者均通过随访研究得到证实（中位数68个月；范围8 - 113个月）。
与先前的报道相反，本研究证明了FNAC作为诊断胸腺增生的一线检查方法的实用性。
