Pulmonary sclerosing pneumocytomas: the rare chameleon of diagnostic thoracic surgery

Background Pulmonary sclerosing pneumocytomas (PSP) are very rare benign intrapulmonary tumors originating from the primitive respiratory epithelium. Usually an incidental finding without symptoms, diagnostic surgery is the treatment of choice.

Methods & Materials During the retrospective 20-year period between January 2005 and January 2025, we reviewed 17 patients (14 female and 3 male) who were diagnosed for PSP. Chest computed tomography (CT) showed a slow-growing, well-circumscribed nodule with homogenous enhancement.

Results The mean age of the cohort was 53 ± 18.6 years. Women were significantly more frequently affected than men (82.4% vs.17.6%). Mean tumor size was 1.2 ± 1.8 cm. The lower lobes of the lungs were the preferred site. Histologically, cuboidal epithelioid surface cells and round stromal cells with predominant papillary differentiation were detected. Thus, PSP may be confused with papillary adenocarcinoma on frozen section analysis. Immunohistochemistry showed expression of TTF-1, CK7, EMA and AE1/3 with low proliferative activity, which finally confirmed the diagnosis of PSP.

Conclusion PSP is a benign tumor without any tendency to recurrence. They occur mainly as an incidental finding in middle-aged women. The possibility of PSP should be considered in middle-aged women in the context of intraoperative frozen section examinations during diagnostic surgery of an indeterminate smooth pulmonary mass. The predominance in women may be due to hormonal factors. Further studies are necessary.

Publikationsverlauf

Artikel online veröffentlicht:
25. August 2025