Pulmonary pneumocytoma

Case contributed by Dr Henry Knipe



Patient Data

Age: 50 years
Gender: Female

Soft tissue density 35 mm mass in the left cardiophrenic angle. Lungs are otherwise clear. No lymphadenopathy. 


A lung wedge 65x35x25 mm with smooth pleura. Sectioning reveals a well circumscribed firm grey subpleural tumor 25x25x20 mm.

Courtesy Dr Alpha Tsui, Department of Pathology, The Royal Melbourne Hospital. 


Sections of the lung show a well-demarcated, moderately cellular tumor. It shows variable morphological patterns. In some parts, there are papillae, which are lined by cuboidal epithelial cells. A second population of stromal round cells is present. The epithelial cells have bland nuclei, inconspicuous nucleoli and moderate amounts of eosinophilic to occasionally clear cytoplasm. In other parts, there are more solid nests. The stroma is focally sclerosed and hemorrhagic. Sparse psammoma bodies are present. Mitoses are difficult to find. There is no evidence of lymphovascular invasion. No visceral pleural invasion is seen. The tumor is completely excised with clear parenchymal margin. The adjacent lung parenchyma is unremarkable. The cuboidal surface cells are TTF-1 and CK7 positive. The stromal round cells are TTF-1 and progesterone receptor positive. 

Courtesy Dr Alpha Tsui, Department of Pathology, The Royal Melbourne Hospital. 

Case Discussion

The main pre-operative differential diagnosis was a carcinoid. However, the pathological features are those of a pulmonary pneumocytoma, which is a benign tumor that was previously known as pulmonary sclerosing hemangioma. 

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Case information

rID: 48683
Published: 23rd Oct 2016
Last edited: 14th Aug 2019
System: Chest
Inclusion in quiz mode: Excluded