SUBSOLİD PULMONER NODÜLLERİN KLİNİK, RADYOLOJİK, METABOLİK VE PATOLOJİK ÖZELLİKLERİNİN DEĞERLENDİRİLMESİ

Abstract

The widespread use of computed tomography (CT) has led to a rise in detected subsolid nodules, yet there is no consensus on follow-up or treatment criteria. This study examines the clinical, radiological, metabolic, and pathological characteristics of these nodules and their interrelationships. The study includes 92 subsolid nodules from 86 patients who underwent surgery at our center, detected on thoracic CT between 2012 and 2022. Patient clinical data were retrospectively obtained from the hospital database, and CT, positron emission tomography (PET)/CT images, and tissue sections were re-evaluated by the respective departments. The patients had a mean age of 61±10 years, with 53.5% female, 73.5% having a smoking history, and 47% a history of malignancy. All nodules were incidentally detected; half were excised immediately, while the others were removed after a follow-up of ≥3 months (median: 29.6, range: 4-134.4 months). Percutaneous biopsy was performed on 43 nodules (46.7%), with a sensitivity of 95.3% and a 2.3% major complication rate. Preoperative CT scans showed that 27 nodules were pure ground-glass, 61 were part-solid, and 4 were solid (having become solid during follow-up). Postoperative pathological diagnoses included 1 atypical adenomatous hyperplasia (AAH), 2 adenocarcinoma in situ (AIS), 26 minimally invasive adenocarcinoma (MIA), 51 invasive adenocarcinoma (IA), 1 squamous cell carcinoma, 3 metastases, and 8 benign lesions. Part-solid nodules showed more frequent air bronchograms, vascular and bronchial signs, and pleural retraction within the nodule structure compared to pure ground-glass nodules, and IA was diagnosed more frequently in part-solid nodules (64% versus 37%; p=0.019). Among pure ground-glass nodules, a coronal long diameter greater than 12 mm could differentiate IA from AAH/AIS/MIA/benign pathologies with 70% sensitivity and 81.3% specificity. In part-solid nodules, a long diameter of the solid component of 7 mm or greater allowed for a similar distinction with 71.8% sensitivity and 66.7% specificity. The presence of both pleural contact and retraction on CT indicated visceral pleural invasion with 66.7% sensitivity and 78.9% specificity. Pathological analysis showed a negative correlation between the lepidic pattern and the coronal long diameter in pure ground-glass nodules, and with the solid component diameter in part-solid nodules. Furthermore, irregular shape of the nodule, presence of air bubbles or cysts within the nodule, vascular signs, pleural retraction, high Brock score, and increased metabolic uptake values on PET/CT were associated with the invasive nature of the nodule. In conclusion, the preoperative radiological and metabolic characteristics of subsolid nodules correlate with their postoperative pathological features. These findings are valuable in guiding long-term follow-up and treatment decisions for subsolid nodules.