Lung metastasis

Lung metastasis, also pulmonary metastasis and metastatic lung disease, is relatively common and generally carries a poor prognosis.

General

• Relatively common.

Microscopic

Features:

• Variable - dependent on site of origin.

Colorectal adenocarcinoma - usually distinctive morphologically:

• Typically gland forming.
  • Ellipsoid/elongated pseudostratified nuclei with moderate nuclear atypia.
  • +/-Dirty necrosis.

Others:

• Urothelial carcinoma - may mimic squamous cell carcinoma of the lung.
• Upper GI adenocarcinoma (e.g. gastric adenocarcinoma) - may mimic lung adenocarcinoma.
• Breast carcinoma - esp. ductal carcinoma of the breast - may mimic lung adenocarcinoma.

IHC

• TTF-1 -ve (may be positive).
• CK20 +ve/-ve (+ve in colorectal carcinoma, -ve in lung primaries).
• GATA3 +ve/-ve (usu. +ve in urothelial carcinoma, -ve in lung primaries).

See also

• Metastasis.