胸腺淋巴上皮样腺炎样增生（LESA-like TH）是一种罕见的胸腺增生形式，其特征是胸腺髓质著名扩张，含有带有生发中心的增殖性淋巴滤泡，而胸腺皮质几乎完全缺失。自2012年首次报道以来，迄今为止仅有少数LESA-like TH病例被文献报道。由于LESA-like TH的罕见性和肿瘤样形态，容易在常规实践中被误诊为其他胸腺常见疾病，如胸腺瘤和淋巴瘤。在此，我们报道了一例52岁的中国女性患者LESA-like TH的病例报告，没有任何不适症状。计算机断层扫描成像显示前纵隔内有一个囊实性肿块，具有良好的边界和多个内部隔板。组织学上，突出的特征是带有生发中心的繁茂淋巴滤泡，以及胸腺上皮细胞的增生和Hassall小体的增殖。然而，富含未成熟T细胞的胸腺皮质几乎完全缺失。此外，成熟浆细胞、淋巴上皮病变和胆固醇裂隙经常可见。我们对该病例做出了LESA-like TH的诊断，并进行了文献回顾，以更好地了解LESA-like TH的临床病理特征，减少误诊。 © 2023. BioMed Central Ltd., part of Springer Nature.

Thymic hyperplasia with lymphoepithelial sialadenitis-like features (LESA-like TH) is a rare form of thymic hyperplasia, characterized by a prominent expansion of the thymic medulla containing hyperplastic lymphoid follicles with germinal centers, while an almost total absence of thymic cortex. Since the first report in 2012, only a few cases of LESA-like TH have been reported in the literature to date. Due to the rarity of LESA-like TH and the tumor-like morphology, it is easy to be misdiagnosed as other common diseases of the thymus in routine practice, such as thymoma and lymphoma.Herein, we present a case report of a 52-year-old Chinese female patient with LESA-like TH, without any discomforting symptoms. Computer-tomography imaging revealed a cystic solid mass in the anterior mediastinum, with well-defined boundaries and multiple internal septa. Histologically, prominent features were florid lymphoid follicles containing germinal centers, as well as hyperplasia of thymic epithelial cells and proliferation of Hassall bodies. However, the thymic cortex rich in immature T cells was almost completely absent. Furthermore, mature plasma cells, lymphoepithelial lesions, and cholesterol clefts were frequently seen.We made a diagnosis of LESA-like TH and performed a literature review to better understand the clinicopathological features of LESA-like TH and reduce misdiagnosis.© 2023. BioMed Central Ltd., part of Springer Nature.