Nonclinical Safety, Pathology Department, Janssen R&D, Beerse, Belgium * Both authors are first authors.
Toxicol Pathol. 2020 Dec;48(8):1017-1024. doi: 10.1177/0192623320965895. Epub 2020 Nov 18.
Two similar benign, nonneoplastic vascular lesions have been described in the lymph nodes of humans and animals: angiomyomatous hamartoma (AMH), which is characterized by the replacement of lymphoid tissue by blood vessels, smooth muscle, and fibrous tissue, and vascular transformation of sinuses (VTS), which is considered a reactive transformation of lymph node sinuses into capillary-like vascular channels. We hereby report a lesion with features common to both lesions in the mediastinal lymph nodes of a 1-year-old beagle dog in a 1-month toxicity study. Grossly, enlargement and red discoloration were observed, while microscopically, the lesion was characterized by effacement of the lymph node parenchyma with replacement by mature blood vessels, smooth muscle, and fibrous tissue, associated with lymphoid atrophy, which is consistent with AMH. However, multifocal areas of anastomosing or plexiform capillary-like channels lined by normal to slightly plump endothelium, similar to those described for VTS, were also present. Immunohistochemistry analysis revealed abundant positive staining for smooth muscle actin and endothelial cells (von Willebrand factor/factor VIII) and the absence of proliferation (Ki67). In conclusion, these lesions most likely represent a mixture of both AMH and VTS.
两种类似的良性、非肿瘤性血管病变已在人和动物的淋巴结中被描述：血管肌脂肪瘤（angiomyomatous hamartoma，AMH），其特征为淋巴组织被血管、平滑肌和纤维组织所取代；窦状血管转化（sinusoidal vascular transformation，VTS），被认为是淋巴结窦状结构向毛细血管样血管通道的反应性转化。我们在此报告一例 1 岁比格犬在 1 个月毒性研究中的纵隔淋巴结病变，其特征符合这两种病变。大体上，观察到淋巴结肿大和红色变色，显微镜下，病变表现为淋巴组织被成熟的血管、平滑肌和纤维组织取代，伴有淋巴组织萎缩，符合 AMH。然而，也存在多灶性吻合或丛状毛细血管样通道，由正常至轻度肿胀的内皮细胞（von Willebrand 因子/因子 VIII）排列，类似于 VTS 中描述的那样。免疫组织化学分析显示平滑肌肌动蛋白和内皮细胞（von Willebrand 因子/因子 VIII）阳性染色丰富，增殖（Ki67）缺失。总之，这些病变很可能代表 AMH 和 VTS 的混合。
