Gross features: A well-encapsulated, firm, grey nodule measured 3.5 x 3 x 2 cm. The surgeon said it had a pedicle attaching it to the visceral pleura. The cut surface was lobulated.

Histologic Features

This photo shows the inner edge of a fibrous tumor, where it was attached to the visceral pleura. Note that tumor has destroyed the pleura here and invaded lung parenchyma. The epithelium present here is non-neoplastic respiratory epithelium. Non-neoplastic epithelium is often incorporated into these tumors. Sometimes epithelial inclusions are lined by mesothelial cells. Both types of epithelial inclusions are keratin-positive with immunohistochemical stains. Note the alveolar macrophages in the air spaces.

Clinical summary Image 2

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