Metastatic disease of the brain: extra-axial metastases (skull, dura, leptomeningeal) and tumour spread

Abstract

Extra-axial intracranial metastases may arise through several situations. Hematogenous spread to the meninges is the most frequent cause. Direct extension from contiguous extra-cranial neoplasms, secondary invasion of the meninges by calvarium and skull base metastases, and migration along perineural or perivascular structures are less common. Leptomeningeal invasion gives rise to tumour cell dissemination by the cerebrospinal fluid (CSF), eventually leading to neoplastic coating of brain surfaces. Contrast-enhanced magnetic resonance (MR) imaging is complementary to CSF examinations and can be invaluable, detecting up to 50% of false-negative lumbar punctures. MR findings range from diffuse linear leptomeningeal enhancement to multiple enhancing extra-axial nodules, obstructive communicating and non-communicating hydrocephalus. Both calvarial and epidural metastases infrequently transgress the dura, which acts as a barrier against tumour spread. Radionuclide bone studies are still a valuable screening test to detect bone metastases. With computed tomography (CT) and MR, bone metastases extending intracranially and primary dural metastases show the characteristic biconvex shape, usually associated with brain displacement away from the inner table. Although CT is better in detecting skull base erosion, MR is more sensitive and provides more detailed information about dural involvement. Perineural and perivascular spread from head and neck neoplasms require thin-section contrast-enhanced MR.

Potential of F-18 PET/CT in the Detection of Leptomeningeal Metastasis

“…When three high-volume LPs are obtained, the sensitivity improves to 90% 3 . CE-MRI of the brain and/or spine should be performed when the clinical suspicion for LM is high because positive findings allow clinicians to diagnose LM even with negative CSF findings or without performing LP altogether [7][8][9] . A majority of patients with LM secondary to breast cancer will have co-existing paren-…”

Perineural invasion progressing to leptomeningeal carcinomatosis: Is the absence of peripheral nerves an important sign?

“…Computed tomography (CT) and MRI remain the core technologies. 2 Lee and colleagues 34 retrospectively reviewed imaging studies of 38 patients with histopathologically proven PNI from head and neck cancers. MRI, CT, and positron emission tomography (PET)-CT scans were included.…”

“…1 LMC is a clinical condition that results from carcinomatous invasion of one or more of the 3 domains of neurologic functions: the cerebral hemispheres, the cranial nerves that traverse the subarachnoid space, or the spinal cord and root. 2 Most commonly, LMC develops from metastatic spread or direct extension of tumor masses into the central nervous system (CNS). Herein, we report a case of a patient with this clinical condition that followed the contiguous extension of carcinoma cells via the perineural space from a primary cutaneous site to the leptomeninges.…”

Calvarial metastasis from papillary thyroid carcinoma: A case report

“…Carcinoma of the breast, prostate, lung, and multiple myeloma are more frequent in adult, while in pediatric patients, neuroblastoma and sarcoma are more often observed [1,2]. However, calvarial metastasis from papillary thyroid carcinoma (PTC) is a very rare situation so there is no consensus on post surgery treatment protocol [3,4].…”