venerdì 21 aprile 2006
Multiple hemorrhagic intracranial metastases from primary lung carcinoma
Noncontrast enhanced CT of the brain reveals multiple high-density brain lesions with surrounding vasogenic edema, suggestive of hemorrhagic metastases (Figure 1 and Figure 2). Post-contrast images demonstrate enhancement of several of the lesions (Figure 3 and Figure 4).
Medialstinal and lung windows from the CT of the chest (not shown)demonstrated the primary lung carcinoma.
Diagnosis: Multiple hemorrhagic intracranial metastases from primary lung carcinoma
Metastatic spread to the brain is usually arterial, although less commonly spread via the Batson venous (pelvic, GI tumors) may occur. Most metastatic lesions are well-demarcated and tend to cluster at the gray-white matter junction.
Most of the brain metastases originate either from a primary lung tumor or from metastatic lesions in the lungs, since most large aggregates of tumor cells are filtered by the lung capillary network. Single tumor cells, however, can pass through the lung capillary network, and larger tumor emboli can pass from the venous to arterial circulation through a patent foramen ovale or a right to left shift.
The most likely malignancies to produce hemorrhagic metastases are melanoma, renal cell carcinoma, choriocarcinoma, thyroid, lung, breast, and germ cell tumors. Due to their increased prevalence, however, bronchogenic lesions are the most common source of hemorrhagic lesions.
Up to 20% of patients with metastases to the brain present with seizures.
Mnemonic MR CT BB
R: Renal cell carcinoma
T: Thyroid, terratoma
B: Bronchogenic carcinoma
B: Breast carcinoma