Liccardi Anthony R, Thomas Kristen, Narula Navneet, Azour Lea, Moreira Andre L, Zhou Fang
Center for Biospecimen Research and Development, Office of Science and Research, New York University Grossman School of Medicine, New York, NY, USA.
Department of Pathology, New York University Langone Health, New York, NY, USA.
Mediastinum. 2022 Aug 22;7:6. doi: 10.21037/med-22-15. eCollection 2023.
In mediastinal biopsies that show fibrosis, the differential diagnosis includes fibrosing mediastinitis, immunoglobulin G subclass 4-related disease, Hodgkin lymphoma, as well as reactive fibrotic and inflammatory changes adjacent to other processes including neoplasms.
We report two cases of incidentally detected mediastinal seminoma that contained extensive areas of paucicellular fibrosis, which precluded accurate preoperative biopsy diagnosis. The fibrosis consisted of mildly inflamed, densely scarred tissue with thin dilated vessels, and was present to a significant extent that is suggestive of spontaneous regression. These features are not currently described in the World Health Organization Classification of Thoracic Tumors. In both patients, needle and open biopsies sampled only the fibrotic areas of the tumors, and the final diagnosis was not achieved until surgical excision was performed. After surgery, both patients received chemotherapy, and were alive without evidence of disease at 3.4 years and 1 year post-operatively, respectively. Tumor fibrosis composed approximately 95% and 50% of each patient's tumor, respectively. In one of the patients, correlation of the needle biopsy position with the positron emission tomography (PET) scan revealed that the biopsy needle had sampled a non-metabolically active portion of the tumor.
While pathologic spontaneous regression is well-described in gonadal germ cell tumors, it is not well-reported in extragonadal locations. Prospective knowledge of this diagnostic pitfall and targeting PET-avid regions of the tumor may increase the diagnostic yield and help to avoid non-indicated surgical interventions.
在显示纤维化的纵隔活检中，鉴别诊断包括纤维性纵隔炎、免疫球蛋白G4相关疾病、霍奇金淋巴瘤，以及与包括肿瘤在内的其他病变相邻的反应性纤维化和炎症改变。
我们报告两例偶然发现的纵隔精原细胞瘤，其中含有广泛的少细胞纤维化区域，这使得术前活检难以准确诊断。纤维化由轻度炎症、致密瘢痕组织和细扩张血管组成，且程度显著，提示自发消退。这些特征目前在世界卫生组织《胸部肿瘤分类》中未被描述。在两名患者中，针吸活检和开放活检仅取材于肿瘤的纤维化区域，直到进行手术切除才得出最终诊断。术后，两名患者均接受了化疗，分别在术后3.4年和1年时存活且无疾病证据。肿瘤纤维化分别约占每名患者肿瘤的95%和50%。在其中一名患者中，针吸活检位置与正电子发射断层扫描（PET）的相关性显示，活检针取材于肿瘤的非代谢活跃部分。
虽然性腺生殖细胞肿瘤中病理性自发消退已有充分描述，但在性腺外部位报道较少。对这一诊断陷阱的前瞻性了解以及靶向肿瘤的PET高摄取区域可能会提高诊断率，并有助于避免不必要的手术干预。
