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Neuroradiology Case of the Week

Case 139

Fariha Ahsan, Ravinder Sidhu, MD, Sudhir Kathuria, MD
and PL Westesson MD, DDS, PhD

Clinical Presentation: A 57-year-old female status breast cancer presented with headache and confusion.

Radiological Findings: NCCT scan showed thickened cortical gyri in the left frontal lobe with slight increased density (Fig. 1). Axial T1-weighted MR image showed thickened cortical gyri (Fig. 2). T2 and FLAIR images revealed hyper intense foci with thickened gyri (Figs. 3A&B). Post contrast images showed irregular, gyral enhancement in left frontal lobe, and cerebellum (Figs. 4A&B).

Discussion: Leptomeningeal metastasis is a clinically important neurological complication of cancer and called meningeal carcinomatosis (MC). It occurs in approximately 1-8% of patients with cancer. Adenocarcinomas are the most common tumors to metastasize to the leptomeninges, although any systemic cancer can do so. Small-cell lung cancers spread to the leptomeninges 9-25% of the time, melanomas 23%, and breast cancers 5%; however, because of the differing relative frequencies of these cancers, most patients with meningeal carcinomatosis have breast cancer.
     Leptomeningeal cancer can invade the brain and spinal parenchyma, nerve roots, and vessels that supply the central nervous system. Pain and seizures are the most common presenting complaints. Other presentations include headaches (usually associated with nausea, vomiting, and lightheadedness), mild gait difficulties from weakness or ataxia, memory problems, incontinence, sensory abnormalities, papilledema and cranial nerve involvement.
     The diagnosis is made with positive CSF cytological results, subarachnoid metastases identified on radiologic studies, or a history and physical examination suggestive of meningeal carcinomatosis along with abnormal CSF findings. Only 50% of the patients have abnormal imaging findings, most commonly contrast enhancement of the basilar cisterns, cortical convexities, cauda equina, or hydrocephalus without a mass legion, but this enhancement usually follows positive cytological findings by 6 months. CT scan may reveal unexplained communicating hydrocephalus or abnormal enhancement of tentorium, sylvian fissures and basal cisterns, cortical subarachnoid space, and ventricular walls.
     Contrast enhanced MR is more sensitive than contrast enhanced CT, especially when most of the meningeal enhancement is against the skull vault. Normal meningeal enhancement is seen as a thin, markedly discontinuous rim covering the surface of the brain. The enhancement is primarily seen in the dura and venous structures. The enhancement pattern depends upon the mode of spread of tumor cells. It may be seen as diffuse, nodular, and sheet like enhancement.

References:

1. Jayson GC, Howell A, Harris M, Morgenstern G, Chang J, Ryder WD. Carcinomatous meningitis in patients with breast cancer. An aggressive disease variant, Cancer 1994 Dec 15;74(12):3135-41. [Medline]
2. Sze G, Soletsky S, Bronen R, Krol G. MR imaging of the cranial meninges with emphasis on contrast enhancement and meningeal carcinomatosis. AJR Am J Roentgenol. 1989 Nov;153(5):1039-49. [Medline]