An accurate diagnosis of Noguchi classification is possible after the modification of preoperative biopsy-induced fibrosis.

ABSTRACT

PURPOSE: After computed-tomography-guided needle biopsy (CTNB), the lung may undergo iatrogenic fibrosis (post-CTNB fibrosis), which can be misdiagnosed as tumor-induced fibrosis. The purpose of the study was to examine if an accurate evaluation of pulmonary adenocarcinoma can be made using the Noguchi classification (type A or B vs. type C), even after CTNB. MATERIALS AND METHODS: The subjects were 71 patients with primary pulmonary adenocarcinoma of 20 mm or less that had been resected surgically after CTNB. Twenty-four patients who did not undergo a preoperative biopsy served as controls. Resected specimens were stained with hematoxylin-eosin (HE) and elastic-fiber staining for a precise observation of fibrosis. RESULTS: The period from CTNB to surgery ranged from 12 to 153 days. Post-CTNB fibrosis consisted primarily of collagen fibers with a few thin elastic fibers observed only with high magnification, which was able to distinguish post-CTNB fibrosis in 39 of 48 patients (81.3%) with bronchioloalveolar carcinoma (BAC) lesions (types A/B/C) and in 6 of 23 patients (26.1%) without BAC lesions (types D/E/F/E + F), showing a significant difference (p <0.0001). In the control group, no lesions that resembled post-CTNB fibrosis were observed. CONCLUSION: An evaluation of pulmonary adenocarcinoma by Noguchi classification can be accurately performed even after CTNB.