Pulmonary sclerosing pneumocytoma demonstrated heterogeneous tumor growth rate on serial CT: a retrospective cohort study.

Background: Pulmonary sclerosing pneumocytoma (PSP) is a rare benign tumor with various manifestations, posing a challenge for accurate diagnosis and appropriate management. Imaging, particularly computed tomography (CT), is crucial for the diagnosis of PSP, and imaging surveillance is adopted as a strategy for the management of PSP patients. However, the natural history and growth patterns of PSP remain poorly characterized, creating an urgent need for evidence-based surveillance protocols to guide clinical management. This study aimed to investigate the CT manifestations and tumor growth patterns of PSP to enhance understanding and provide evidence for the clinical management of PSP patients. Methods: A retrospective observational cohort study was conducted among PSP patients diagnosed between August 2014 and August 2025 at a single tertiary hospital in southwestern China. Inclusion criteria were: (I) histopathologically diagnosed PSP registered in the pathology information system; (II) available preoperative chest CT; and (III) complete clinical records. Exclusion criteria included: (I) incorrect diagnosis of PSP; (II) incomplete CT data or CT of poor quality; and (III) prior lung surgery or malignancy affecting follow-up assessment. Baseline clinical factors (age, sex, symptoms, smoking history) and CT features (size, location, morphology, calcification, enhancement patterns) were systematically recorded. For 17 patients with serial CT scans, tumor volume doubling time (TVDT) was calculated using the modified Schwartz formula. Growth patterns were classified as stable or no growth [volume doubling time (VDT) >6,000 days], slow or indolent (600-6,000 days), and rapid (<600 days) according to the TVDT. The predefined primary outcome was tumor growth kinetics; secondary outcomes included CT characteristics and postoperative recurrence. Results: The cohort was predominantly female, with a mean age of 48.4±12.5 years at the time of diagnosis. Most patients were asymptomatic. All of the PSP lesions manifested as solitary, well-circumscribed nodules or masses, predominantly in the lower lobes. The top three most common CT features observed in PSP included oval shape, calcification, and significant enhancement after contrast administration. Twenty-five out of 68 patients were correctly diagnosed as PSP preoperatively. Among 17 cases with serial CT, 5 (29.4%) showed no growth, 6 (35.3%) showed slow growth, and 6 (35.3%) showed rapid growth. All patients underwent surgical resection with no recurrence or metastasis observed. Conclusions: This study indicates that PSP might have characteristic features, and radiological features may suggest the diagnosis of PSP. PSP exhibits heterogeneous growth patterns ranging from no growth to slow-growing and rapid-growing rates. These findings suggest that individualized surveillance intervals should be adopted for PSP-suspicious nodules: while some PSP cases with no growth or slow-growing rates may permit extended follow-up, cases with rapid growth warrant shorter follow-up intervals. This evidence supports tailored clinical management for PSP patients.