An Unusual Cause of Mosaic Attenuation.
An Unusual Cause of Mosaic Attenuation.
复制标题
马赛克衰减的异常原因。
DOI：
10.1164/rccm.201908-1618im
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发表时间：
2020
影响因子：
24.7
通讯作者：
Cagnina,RElaine
中科院分区：
文献类型：
--
作者：
Weinberger,JeremyF;Lo,Ying-Chun;Vargas,SaraO;Cagnina,RElaine
一位68岁女性，有慢性粒单核细胞白血病病史，因呼吸急促和低氧血症而入院。她从不吸烟，没有肺部疾病的病史。白细胞增加到75K/ml、单核细胞占51%、外周血细胞占20%时，全血细胞计数显著增加。骨髓活检证实转化为急性粒-单核细胞白血病。胸部CT(图1A和1B)显示弥漫性的支气管血管周围实变、小叶间隔增厚和广泛的马赛克衰减。由于氧气需求高和血小板减少，支气管镜检查被推迟，她接受了可能的潜在感染病因的经验性治疗；然而，广泛的感染检查没有揭示出来。她开始使用羟基脲进行细胞减少，反应良好，细胞计数和低氧血症得到改善。患者于1个月后复诊，开始用氮胞苷和万乃馨进行第一周期化疗。再次入院时，她的白细胞计数为13.15K/ml，其中单核细胞占26%，原始细胞占12%。入院期间重复胸部CT(图1C和图1D)显示，支气管血管周围固结完全消失，但仍存在广泛的马赛克衰减。由于持续的氧气需求和马赛克，她接受了BAL支气管镜检查和经支气管镜活检。来自BAL的感染性研究，包括肺炎的检测，都是阴性的，经纤维支气管镜检查显示含铁血黄素沉着症和少量的粒单核细胞聚集(图2)符合白血病的浸润性。白血病的浸润性和相关的呼吸衰竭是AMML的常见现象，可能是疾病的表现[1]。白血病浸润性病变有许多CT表现，包括小叶间隔增厚、突出的肺血管以及实变性、磨玻璃样和结节状阴影[2]。肿瘤粒单核细胞保留功能，包括吞噬功能、免疫球蛋白G和补体受体活性以及粒细胞集落刺激因子的产生，因此很难将白血病浸润物(代表对任何数量的肺部损伤的炎症反应)从白血病原发浸润物中分离出来(3)。此外，支气管周围间质中的AMML肿瘤细胞(如图所示)，或空隙中的潜在细胞，可能会影响空气通过小气道的运动，导致空气滞留和
A 68-year-old female with a history of chronic myelomonocytic leukemia was admitted for increasing shortness of breath and hypoxemia. She was a never smoker without a history of lung disease. Complete blood count was notable for leukocytosis of 75 K/ml with 51% monocytes and 20% peripheral blasts. Bone marrow biopsy confirmed transformation to acute myelomonocytic leukemia (AMML). Computed tomography (CT) of the chest (Figures 1A and 1B) showed diffuse peribronchovascular consolidations, interlobular septal thickening, and widespread mosaic attenuation. Given high oxygen requirements and thrombocytopenia, bronchoscopy was deferred, and she was treated empirically for possible underlying infectious etiologies; however, a broad infectious workup was unrevealing. She was started on hydroxyurea for cytoreduction with good response and improvement in cell counts and hypoxemia. The patient returned 1 month later to initiate cycle one of chemotherapy with azacytidine and venetoclax. At the time of readmission, her white blood cell count was 13.15 K/ml with 26% monocytes and 12% blasts. Repeat CT of the chest during this admission (Figures 1C and 1D) showed complete resolution of peribronchovascular consolidations but persistence of widespread mosaic attenuation. Given ongoing oxygen requirement and mosaicism, she underwent bronchoscopy with BAL and transbronchial biopsies. Infectious studies from the BAL, including testing for Pneumocystis jiroveci pneumonia, were negative, and transbronchial biopsy showed hemosiderosis and a small peribronchial collection of myelomonocytic forms (Figure 2) consistent with leukemic infiltrate.Leukemic infiltrate with associated respiratory failure is a well-described phenomenon in AMML and may be a presenting sign of disease (1). Numerous CT findings have been described in leukemic infiltrate, including interlobular septal thickening, prominent pulmonary vasculature, as well as consolidative, ground-glass, and nodular opacities (2). Neoplastic myelomonocytic cells retain functional capacity, including phagocytosis, IgG and complement receptor activity, and granulocyte colony–stimulating factor production, and therefore it is difficult to separate a leukemic infiltrate (representing an inflammatory response to any number of pulmonary insults) from a “primary” leukemic infiltrate (3). In addition, AMML neoplastic cells in the peribronchial interstitium (as pictured here), or potentially cells in the airspace, may impinge on air movement through small airways, resulting in air trapping and