Pleural solitary fibrous tumor

Case contributed by Dr Henry Knipe


Chronic cough.

Patient Data

Age: 45
Gender: Female

Large right lower lobe mass. Left lung is clear. Normal cardiomediastinal contour. 


Very large right lower lobe mass with marked vascularity. Broad pleural attachment posteriorly. No chest wall invasion. No lymphadenopathy. 


CLINICAL NOTES: R lung mass 150 x 110 x 80 mm. The piece is roughly pyramidal in shape with multiple staple lines, 10-85mm. On one side is a thick pale glassy plaque over the surface 170 x 60 mm. The remainder of the tissue has a white/pale/deep red, partially smooth and vaguely nodular surface. A few dilated vessels are seen, that have smooth pale walls <1mm thick. There is a relative well circumscribed area that is firm lobular and with a whorled appearance, 40 mm in greatest dimension.

MICROSCOPIC DESCRIPTION: The sections show a tumor, surrounded by a small amount of lung tissue. The tumor shows mild to moderate increase in cellularity, forming short fascicles. There are intermixed areas of fibrosis in the background. The tumor cells have elongated nuclei with no nuclear pleomorphism, inconspicuous nucleoli and ill-defined cytoplasm. There are scattered staghorn type blood vessels in the stroma. Sparse mitoses are noted, less than 4 per 10 high power fields. No necrosis is present. There is no evidence of lymphovascular invasion. The tumor cells are CD34, CD99 and bcl-2 positive. The Ki-67 index is about 2%. They are EMA, CAM5.2 and TTF-1 negative. The features are those of solitary fibrous tumor. It appears completely excised. Its behavior cannot be predicted on histology alone.

DIAGNOSIS: Right lung mass: Solitary fibrous tumor. 

Case Discussion

Pleural solitary fibrous tumors are rare benign pleural-based tumors that accounts for <5% of all tumors involving the pleura.

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Case information

rID: 51027
Published: 15th Feb 2017
Last edited: 3rd Feb 2021
System: Chest
Inclusion in quiz mode: Included