The first case of a solitary peripheral adenopapilloma of the lung with a risk of cancer.

Background: Solitary peripheral ciliated adenopapilloma of the lung (SPCAP) is a rare benign lung tumor, rarely located in the peripheral lung, and there is no report of canceration. Our case report suggests that it is likely to be cancerous. SPCAP classification remains inconclusion.Therefore, our case report can enrich the pathological database, improve clinicians' understanding of this disease and provide help for clinical diagnosis.

Case presentation: A 41-year-old woman found a pulmonary nodule for 2 years by chest computed tomography (CT) and this chest -enhanced CT follow-up found that the wall of the nodule was slightly thickened, which could not rule out malignant tumor. Therefore, we recommend that patients be hospitalized for surgery.The patient had no notable habits such as a smoking history, drug dependence, or history of sexual misconduct. Physical examination and blood tumor markers were normal. Initially diagnosed with a benign lung tumor, SPCAP was finally diagnosed by thoracoscopic wedge resection of the right lower lobe, accompanied by a small area of atypical adenomatous hyperplasia of the alveolar epithelium.One week after the operation, the patient re-examined the chest CT, and was discharged without secondary lesions.

Conclusions: SPCAP is a benign tumor with no previous reports of carcinoma in the literature, and the pathological manifestations of our case suggest atypical adenomatous hyperplasia and nuclear atypia.This may suggest the possibility of cancerous transformation of this tumor, and this case provides more knowledge about this tumor and it also provides a basis for surgical treatment.