M1

Fig. 29: M1 disease. Three enhancing metastases of lung cancer are present in this contrast enhanced T1 magnetic resonance image of the brain.

M1 designates metastasis to distant organ and lymph node sites. It is used also to designate discontinuous tumor lesions outside the parietal pleura in the chest wall or in the diaphragm, and to classify metastasis in ipsilateral non-primary tumor lobe(s).

Fig. 30: M1 disease. A computed tomographic scan of the abdomen shows metastatic lung cancer to the right adrenal gland. The gland is enlarged (arrow) and shows areas of decreased attenuation in keeping with necrosis.