Xu Jie, Wu Xiaojun, Reddy Vishnu
Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35244, USA; Department of Hematopathology, MD Anderson Cancer Center, Houston, TX 77030, USA.
Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35244, USA; Department of Pathology, George Washington University Hospital, Washington, DC 20037, USA.
Case Rep Hematol. 2016;2016:2942594. doi: 10.1155/2016/2942594. Epub 2016 Jan 20.
T cell/histiocyte-rich large B cell lymphoma (THRLBCL) is predominantly a nodal disease, with extranodal involvement, such as bone marrow, spleen, and liver. However, primary THRLBCL has never been reported in the thymus in the English literature. Here we report a case of THRLBCL presenting as mediastinal mass and lymphadenopathy. Based on the frozen section diagnosis of "thymoma," a 12 cm mass was excised. A year later she developed multiple enlarged lymph nodes and pulmonary nodules. Consultant review of the excised mediastinal mass showed scattered large atypical cells that were CD20+ and PAX-5+ and negative for pan-cytokeratin, AE1, and AE3, compatible with THRLBCL and excluding thymoma. The excised lymph nodes were replaced by diffuse infiltrate of small CD3+ lymphocytes and histiocytes with intermingled large CD20+ B lymphoma cells scattered throughout the section. A diagnosis of THRLBCL was made in lymph node, similar to previous thymic lesion. A clonal rearrangement of immunoglobulin heavy chain (IGH) gene was detected, further supporting the diagnosis. This is the first reported case of THRLBCL in thymus. Correct recognition of this entity is critical, because of the difference in therapeutic impact on these patients.
富于T细胞/组织细胞的大B细胞淋巴瘤（THRLBCL）主要是一种淋巴结疾病，可出现结外受累，如骨髓、脾脏和肝脏。然而，英文文献中从未报道过原发性THRLBCL发生于胸腺。在此，我们报告1例表现为纵隔肿块和淋巴结病的THRLBCL。基于“胸腺瘤”的冰冻切片诊断，切除了一个12厘米的肿块。一年后，她出现多个肿大淋巴结和肺结节。对切除的纵隔肿块进行会诊复查显示，有散在的大的非典型细胞，CD20+、PAX-5+，全细胞角蛋白、AE1和AE3均为阴性，符合THRLBCL，可排除胸腺瘤。切除的淋巴结被小的CD3+淋巴细胞和组织细胞弥漫浸润，其间散在大的CD20+B淋巴瘤细胞，贯穿整个切片。淋巴结诊断为THRLBCL，与先前的胸腺病变相似。检测到免疫球蛋白重链（IGH）基因的克隆重排，进一步支持该诊断。这是首次报道的胸腺THRLBCL病例。正确识别这一实体至关重要，因为对这些患者的治疗影响有所不同。
