Ma YanLing, Gal Anthony, Koss Michael
Department of Lung Pathologist, KEck Medical Center of USC, Los Angeles, California.
Department of Pathology, Emory School of Medicine, Atlanta, Georgia.
Semin Diagn Pathol. 2018 Sep;35(5):324-333. doi: 10.1053/j.semdp.2018.09.001. Epub 2018 Sep 24.
Sarcoidosis is a multi-system disease of unknown etiology, usually affecting the respiratory tract and other organs, and is characterized by the formation of nonnecrotizing epithelioid granulomas. The diagnosis depends on a combination of a typical clinicoradiological presentation, the finding of nonnecrotizing epithelioid granulomas in a tissue biopsy, and exclusion of other possible diseases, especially those of infectious etiology. The granulomas contain epithelioid cells, giant cells, CD4+ T cells in their center, and CD8+ T lymphocytes and B lymphocytes at their periphery. The granulomas are present in a lymphatic pattern around bronchovascular structures and, because of this, may show angioinvasion. The bronchial involvement produces a high diagnostic yield for transbronchial and endobronchial biopsies in this disease. Finally, small amounts of fibrinoid necrosis may occur within granulomas of sarcoidosis and do not exclude the diagnosis. Larger amounts suggest either infection or the rare disease necrotizing sarcoid granulomatosis (NSG). A number of cytoplasmic structures/inclusions can be identified within the granulomas of sarcoidosis, including asteroid bodies, Schaumann's bodies, calcium oxalate crystals, and Hamazaki-Wesenberg bodies; the last two of these can cause difficulties in differential diagnosis. Extra-pulmonary sarcoid can be an important factor in prognosis. Involved sites include (in decreasing frequency): skin, endocrine organs, extra-thoracic lymph nodes, neurologic sites, eyes, liver, spleen, bone marrow, cardiac, ear/nose/throat, parotid/salivary, muscles, bones/joint, and kidney. NSG is a controversial variant of sarcoidosis consisting of granulomatous pneumonitis with sarcoid-like granulomas, variable amounts of necrosis, and granulomatous vasculitis. The lesions are most often confined to lung, and they usually appear as multiple nodules or nodular infiltrates, but occasionally as solitary or unilateral nodules ranging up to 5 cm in diameter. Nodular sarcoidosis is rare, varying from 1.6% to 4% of patients with sarcoidosis, and, as the name suggests, it shows radiographic nodules measuring 1 to 5 cm in diameter that typically consist of coalescent granulomas. Lung transplantation can be used in selected patients with fibrotic late-stage sarcoidosis. There is a high reported frequency of recurrence of disease in the pulmonary allograft, ranging from 47% to 67%, but recurrence is usually not clinically significant. Studies of the pathogenesis of sarcoidosis suggest that it is a chronic immunological response produced by a genetic susceptibility and exposure to specific environmental factors.
结节病是一种病因不明的多系统疾病，通常累及呼吸道和其他器官，其特征是形成非坏死性上皮样肉芽肿。诊断取决于典型的临床放射学表现、组织活检中发现非坏死性上皮样肉芽肿以及排除其他可能的疾病，尤其是感染性病因的疾病。肉芽肿中央含有上皮样细胞、巨细胞、CD4+T细胞，周边含有CD8+T淋巴细胞和B淋巴细胞。肉芽肿以淋巴管样模式存在于支气管血管结构周围，因此可能显示血管侵犯。支气管受累使得经支气管和支气管内活检在该疾病中有较高的诊断率。最后，结节病肉芽肿内可能会出现少量纤维蛋白样坏死，但这并不排除诊断。大量纤维蛋白样坏死提示感染或罕见的坏死性结节病肉芽肿病（NSG）。在结节病肉芽肿内可识别出一些细胞质结构/包涵体，包括星状体、舒曼小体、草酸钙晶体和哈马扎基-韦森堡小体；其中后两者可导致鉴别诊断困难。肺外结节病可能是影响预后的重要因素。受累部位包括（频率递减）：皮肤、内分泌器官、胸外淋巴结、神经部位、眼睛、肝脏、脾脏、骨髓、心脏、耳鼻喉、腮腺/唾液腺、肌肉、骨骼/关节和肾脏。NSG是结节病的一种有争议的变异型，由肉芽肿性肺炎伴结节病样肉芽肿、不同程度的坏死和肉芽肿性血管炎组成。病变最常局限于肺部，通常表现为多个结节或结节状浸润，但偶尔也表现为直径达5厘米的孤立或单侧结节。结节性结节病罕见，占结节病患者的1.6%至4%，顾名思义，它表现为直径1至5厘米的放射学结节，通常由融合的肉芽肿组成。肺移植可用于选定的晚期纤维化结节病患者。据报道，肺移植中疾病复发的频率较高，在47%至67%之间，但复发通常在临床上无显著意义。结节病发病机制的研究表明，它是由遗传易感性和接触特定环境因素产生的慢性免疫反应。
