Hirokawa Yu, Michiwaki Yuhei, Tanaka Tatsuya, Kawashima Masatou, Wakamiya Tomihiro, Sashida Ryohei, Shimoji Kazuaki, Suehiro Eiichi, Onoda Keisuke, Yamane Fumitaka, Matsuno Akira
J Neurosurg Case Lessons. 2022 Dec 12;4(24). doi: 10.3171/CASE22433.
Thrombotic aneurysms at the nonbranching segment of the distal anterior cerebral artery (ACA) are extremely rare and difficult to differentiate from cavernous malformations by radiographic features alone.
Computed tomography and magnetic resonance imaging of a 30-year-old female patient with a chronic headache complaint revealed a 22-mm frontal lobe mass. The mass showed heterogeneous mixed intensity and hemosiderin deposits on magnetic resonance images. It was not visualized by conventional angiography, indicating that the mass and ACA/other vessels were not connected. The patient was preoperatively diagnosed with a cavernous malformation. However, during resection, the mass surface was white and smooth, different from a cavernous malformation. Although the mass was adherent to the pericallosal artery branch, no luminal continuity was observed. After detachment, the mass was completely resected. Pathological and immunohistochemical findings indicated a vessel wall and interior thrombus. The patient was rediagnosed with a thrombotic aneurysm at the distal ACA nonbranching segment and discharged 10 days postsurgery without neurological deficits.
Because radiographic findings of thrombotic aneurysm and cavernous malformation are similar, mass lesions in contact with major arteries should be differentiated as thrombotic aneurysms, even when the artery lumen appears disconnected from the mass.
大脑前动脉（ACA）远端非分支段的血栓性动脉瘤极为罕见，仅通过影像学特征很难与海绵状畸形相鉴别。
一名30岁有慢性头痛症状的女性患者的计算机断层扫描和磁共振成像显示额叶有一个22毫米的肿块。该肿块在磁共振图像上表现为不均匀混合密度及含铁血黄素沉积。常规血管造影未显示该肿块，表明肿块与ACA/其他血管不相连。该患者术前被诊断为海绵状畸形。然而，在切除过程中，肿块表面呈白色且光滑，与海绵状畸形不同。尽管肿块与胼周动脉分支粘连，但未观察到管腔连续性。分离后，肿块被完全切除。病理和免疫组化结果显示为血管壁和内部血栓。该患者被重新诊断为ACA远端非分支段的血栓性动脉瘤，术后10天出院，无神经功能缺损。
由于血栓性动脉瘤和海绵状畸形的影像学表现相似，即使动脉管腔看似与肿块不相连，与主要动脉接触的肿块性病变也应鉴别为血栓性动脉瘤。
