HRCT features of surgically resected invasive mucinous adenocarcinoma associated with interstitial pneumonia

BACKGROUND AND OBJECTIVE: Lung cancer is prevalent among patients with interstitial pneumonia (IP). HRCT findings mucinous adenocarcinoma in patients with IP have not been described. METHODS: In 112 consecutive patients with 120 surgically resected IP-associated lung cancers, 42 patients had pathologically proven invasive adenocarcinoma (IA). A total of 14 out of 42 patients (10 men, 4 women, mean age, 68.4 years) had invasive mucinous adenocarcinoma. We reviewed the patients' medical records and HRCT scans. RESULTS: Invasive mucinous adenocarcinoma were most commonly associated with idiopathic IP (n = 13) affecting the lower lobe adjacent to a fibrocystic changes. In 11 patients with invasive mucinous adenocarcinoma or other types of IA, the tumour was adjacent to a fibrocystic lesion. In invasive mucinous adenocarcinoma, malignant signs included lobulation (n = 11), spiculation (n = 9), vascular convergence (n = 10) and pleural indentation (n = 2). Characteristic findings of mucinous adenocarcinoma (i.e. vague margins (n = 10), lobular-bounded margins (n = 11), air bronchogram (n = 11) and bubble-like low attenuation (n = 8)) were more common in invasive mucinous adenocarcinoma than in other IA types. All invasive mucinous adenocarcinoma tumours (n = 11) were closely associated with fibrosis. CONCLUSION: Mixed ground-glass opacity and consolidation adjacent to a fibrocystic lesion with malignant signs and characteristic features of mucinous adenocarcinoma indicate malignancy.