Katsuragawa Hiroyuki, Ito Hiroaki, Handa Tomohiro, Hamaji Masatsugu, Menju Toshi, Sakamoto Ryo, Date Hiroshi, Haga Hironori, Yoshizawa Akihiko
Department of Diagnostic Pathology, Kyoto University Hospital, Kyoto, Japan.
Department of Diagnostic Pathology, Kyoto University Hospital, Kyoto, Japan.
Mod Pathol. 2025 Mar;38(3):100675. doi: 10.1016/j.modpat.2024.100675. Epub 2024 Nov 29.
Fibroblastic foci (FF) are considered important findings of usual interstitial pneumonia (UIP); however, they are not only specific to UIP but also observed in various fibrotic interstitial lung diseases (ILDs). Previous studies have reported the significance of FF comparing UIP with nonspecific interstitial pneumonia (NSIP) or secondary interstitial pneumonia, such as collagen vascular disease-related ILD (CVD-ILD) or fibrotic hypersensitivity pneumonitis (FHP). However, only few studies have mentioned their location, and no reports have shown significant results regarding their location. This study aimed to compare the spatial distribution of FF across various forms of ILDs, based on anatomical location. Among patients who underwent lung transplantation at Kyoto University Hospital between April 1, 2008, and March 31, 2023, those diagnosed with idiopathic pulmonary fibrosis (IPF) (n = 24), idiopathic NSIP (n = 11), CVD-ILD (n = 36), and FHP (n = 12) were included, and 744 slides were obtained. FF were classified into 4 categories: peripheral, such as subpleural/paraseptal; intralobular, along the alveolar wall (aFF); centrilobular (cFF); and distorted or dense fibrotic lesions. The number of total and each location's FF/cm were counted, and the percentage of each location's FF was calculated. IPF showed more total FF and peripheral FF than NSIP. FHP had more cFF than CVD (P = .026) and NSIP (P = .018). The dFF was higher in IPF than that in CVD (P = .018) and NSIP (P = .039). The aFF/total FF ratio was higher in CVD than that in FHP (P = .021) and IPF (P < .001). A high cFF/total FF ratio was correlated with FHP versus IPF (P = .032). In conclusion, FF with existing peripheral and distorted/dense fibrosis were more closely related to IPF, whereas cFF were highly correlated with FHP. Moreover, a high aFF/total FF ratio was suggestive of CVD.
成纤维细胞灶（FF）被认为是普通间质性肺炎（UIP）的重要表现；然而，它们并非UIP所特有，在各种纤维化间质性肺疾病（ILD）中也可见到。既往研究报道了FF在比较UIP与非特异性间质性肺炎（NSIP）或继发性间质性肺炎（如胶原血管病相关ILD（CVD-ILD）或纤维化性过敏性肺炎（FHP））方面的意义。然而，仅有少数研究提及它们的位置，且尚无关于其位置的显著研究结果报道。本研究旨在根据解剖位置比较不同形式ILD中FF的空间分布。在2008年4月1日至2023年3月31日期间于京都大学医院接受肺移植的患者中，纳入诊断为特发性肺纤维化（IPF）（n = 24）、特发性NSIP（n = 11）、CVD-ILD（n = 36）和FHP（n = 12）的患者，共获得744张切片。FF分为4类：外周型，如胸膜下/间隔旁型；小叶内型，沿肺泡壁（aFF）；小叶中心型（cFF）；以及扭曲或致密的纤维化病变。计算每个部位FF/cm的总数和数量，并计算每个部位FF的百分比。IPF的FF总数和外周FF比NSIP更多。FHP的cFF比CVD（P = .026）和NSIP（P = .018）更多。IPF的dFF高于CVD（P = .018）和NSIP（P = .039）。CVD的aFF/FF总数比值高于FHP（P = .021）和IPF（P < .001）。高cFF/FF总数比值与FHP相对于IPF相关（P = .032）。总之，存在外周及扭曲/致密纤维化的FF与IPF关系更密切，而cFF与FHP高度相关。此外，高aFF/FF总数比值提示CVD。
