Pulmonary sclerosing pneumocytoma

Pulmonary Sclerosing Pneumocytoma (PSP) is a rare lung tumor that predominantly affects adult women. It was previously known as sclerosing hemangioma of the lung. Despite its name, PSP is neither a hemangioma nor particularly sclerosing. It is a benign neoplasm of uncertain histogenesis, although it is believed to originate from primitive respiratory epithelium.

Epidemiology

Pulmonary Sclerosing Pneumocytoma is an uncommon tumor, with a higher incidence in Asian populations. It has a marked female predominance, with a female-to-male ratio of approximately 5:1. The age of presentation is usually between 30 and 50 years, but cases have been reported in a wide age range.

Clinical Presentation

Patients with PSP may be asymptomatic, with the tumor often discovered incidentally during routine chest imaging. When symptoms do occur, they can include cough, chest pain, hemoptysis (coughing up blood), and dyspnea (difficulty breathing). However, these symptoms are non-specific and can be associated with a variety of lung conditions.

Pathology

Macroscopically, PSP appears as a well-circumscribed, non-encapsulated, lobulated mass that can vary in size. Histologically, it is characterized by two main cell types: surface cells and round cells. The surface cells are cuboidal or flat and line papillary structures, while the round cells are found in solid areas. The tumor also exhibits four histological patterns: solid, papillary, sclerotic, and hemorrhagic, which can coexist in varying proportions within the same tumor.

Diagnosis

The diagnosis of PSP is primarily based on imaging and histological examination. On Computed Tomography (CT) scans, PSP typically presents as a well-defined, solitary nodule that may show a slight enhancement after contrast administration. Definitive diagnosis, however, requires histopathological examination, often following surgical resection.

Treatment and Prognosis

Surgical resection is the treatment of choice for PSP, with lobectomy being the most common procedure. Given its benign nature, the prognosis after complete resection is excellent, with very low rates of recurrence or metastasis. However, long-term follow-up is recommended due to the rare possibility of recurrence.

Differential Diagnosis

The differential diagnosis for PSP includes a variety of benign and malignant lung tumors, such as adenocarcinoma, metastatic tumors, and other rare lung tumors. Accurate diagnosis relies on a combination of radiological and histopathological findings.

Conclusion

Pulmonary Sclerosing Pneumocytoma is a rare, benign lung tumor with a favorable prognosis following surgical resection. Its unique histological features and predominance in adult women make it a distinct entity among lung tumors. Ongoing research into its pathogenesis and long-term outcomes will continue to improve our understanding and management of this uncommon condition.

NIH genetic and rare disease info

• NIH info on Pulmonary sclerosing pneumocytoma

Pulmonary sclerosing pneumocytoma is a rare disease.