Pseudocavity on Thin-slice CT Can Be a Suggestion of Bronchiolar Adenoma: A Preliminary Study on 80 Cases With Bronchiolar Adenoma of the Lung.

Objectives: At present, the study of bronchiolar adenoma (BA) mainly focuses on its pathologic characteristics, but there is limited understanding of its clinical manifestations and imaging signs. This article aims to summarize the clinical manifestations and imaging features of 80 cases of BA, with the goal of achieving a comprehensive and systematic understanding of BA.

Materials and methods: We retrospectively analyzed 80 patients with BA confirmed by surgical pathology in our hospital. All subjects underwent thin-slice CT examination. The basic information, tumor history, clinical manifestations, and CT imaging features of the lesions were collected. The subjects' age, maximum diameter of BA, and shortest distance from the pleura were analyzed by t-test or 1-way ANOVA, while other clinical and radiologic characteristics were compared for differences among different BA types by the χ2 test or Fisher exact probability method.

Results: The majority of the 80 patients were female, with an average age of 59.08±10.16 years. The majority of them do not manifest any clinical symptoms. All lesions are located in the subpleural area, including 63 cases in the lower lobe of the lungs. The average size of the tumors was 10.31±5.01 mm. The majority of the lesions exhibited irregular morphology (53 cases, 66.25%) and predominantly comprised solid nodules (46 cases, 57.50%). There were statistically significant differences in lesion morphology, boundary, and pseudocavity among pure ground-glass nodular BA, mixed ground-glass nodular BA, and solid density nodular BA. Compared with pure ground-glass density BA (1 case, 1.25%) and mixed ground-glass density BA (7 cases, 8.75%), the boundary of solid nodules BA (42 cases, 52.50%) was significantly clearer (P<0.001). The presence of pseudocavity was found to be significantly higher in individuals with solid nodules compared with those with pure ground-glass nodules (P<0.0167). Compared with BA without pseudocavity, BA with pseudocavity exhibited a clearer lung interface (P<0.001), more abnormal vessel signs (P=0.007), and a higher incidence of malignant preoperative diagnosis (P=0.020).

Conclusions: BA mostly occurs in middle-aged and elderly women without any clinical symptoms. The imaging manifestations of BA are diverse, mainly presenting as irregular solid nodules. The interface between the tumor and lung is clear, and pseudocavity formation is common. In addition, BA with pseudocavity often exhibits abnormal vascular signs, which can lead to misdiagnosis as malignancy before surgery.