Pulmonary sclerosing pneumocytoma masquerading as lung metastasis: A case report

Pulmonary sclerosing pneumocytoma (PSP) is a rare benign neoplasm primarily affecting middle-aged Asian women. Although typically presenting as a well-circumscribed solitary nodule with an indolent clinical course, PSP can occasionally exhibit aggressive radiological features. In patients with a history of malignancy, these atypical findings can lead to a significant diagnostic dilemma, frequently mimicking metastatic disease.

A 42-year-old female with a history of breast cancer was referred for evaluation of a lung nodule identified during surveillance. Contrast-enhanced chest computed tomography (CT) revealed a 1.6-cm juxtapleural mass in the right middle lobe. Notably, the lesion showed apparent vessel abutment and suspected vascular invasion, leading to a presumptive radiological diagnosis of angioinvasive metastasis. F-fluorodeoxyglucose positron emission tomography/CT demonstrated low F-fluorodeoxyglucose uptake with a maximum standardized uptake value of 1.6.

Despite the preoperative suspicion of malignancy based on aggressive CT features, the diagnosis of PSP was confirmed through histopathological examination following surgical intervention.

The patient underwent an open wedge resection. Intraoperative findings revealed a well-demarcated mass without inflammatory adhesions or pericardial involvement.

The postoperative course was uneventful, and no recurrence was observed during the follow-up period.

This case highlights that PSP can radiologically masquerade as angioinvasive metastasis, especially in oncological patients. Clinicians and radiologists should consider PSP as a differential diagnosis for solitary pulmonary nodules with suspected vascular invasion, even when positron emission tomography/CT shows low metabolic activity. Histopathological confirmation remains the gold standard for avoiding overdiagnosis and unnecessary radical treatment.