Contributed by Ali Mahta, MD1, Ryan Y Kim, BA1, Ali G. Saad, MD2, Santosh Kesari, MD, PhD1
1Department of Neurosciences, Moores Cancer Center, UC San Diego, 3855 Health Sciences Drive, La Jolla, CA 92093-0819
2Department of Pathology, University of Arkansas for Medical Sciences, 4301 West Markham, Little Rock AR 72205
CLINICAL HISTORY AND IMAGING
A 47-year-old white, right-handed man presented with abrupt onset of left leg numbness while he was at work. He walked around to try to restore circulation when it suddenly became paralyzed and noticed his left arm and leg began to contract rhythmically and involuntarily. There was no report of eye deviation, face involvement, or loss of consciousness. At the time of arrival to the hospital, the movements had stopped. He had no prior history of seizure or stroke. His past medical history was significant for migraine headaches, sinus allergies, chronic uveitis and a history of parathyroidectomy in the past. He had an episode of severe uveitis at age eight with bilateral eye redness and soreness and was treated with steroids and Cytoxan. His medications were oxymetazoline nasal spray for nasal congestion and daily prednisolone eyedrops. He has a 20-year history of tobacco use and drinks alcohol socially. He denied any unusual exposure history and to his knowledge had never been exposed to tuberculosis. His family history was notable for a mother with breast cancer, and sister with Sjögren's syndrome who had uveitis as well.
On admission vital signs were unremarkable. He was awake, alert, and following commands. The physical and neurological exam was only remarkable for decreased sensation to light touch on his left lower extremity. Complete blood cell count and metabolic panel were all within normal limits. He was started on phenytoin 100 milligrams po tid and dexamethasone 8 milligrams iv q4h. MRI of the brain demonstrated an intra-axial mass in the post-central gyrus, measuring 2.7 x 1.5 x 2.2 cm: it was slightly hyperintense on T1 (Figure 1a), enhanced with gadolinium peripherally (Figure 1b) and hypointense on FLAIR with surrounding edema (Figure 1c). A CT scan of the chest, abdomen and pelvis demonstrated paraesophageal and mediastinal adenopathy with calcifications and was otherwise negative. Given his history and clinic findings, he was felt to most likely have metastatic disease to the brain and resection was recommended. A craniotomy was performed with resection of the right parietal brain mass.
Histologic examination of the resected specimen showed cerebral gray and white matter. At the gray-white matter junction, multiple non caseating granulomata were identified (Figure 2). The adjacent gray and white matter showed reactive gliosis but no evidence of a neoplastic process was noted. Scattered blood vessels with perivascular lymphocytes were also present including the leptomeninges. Each granuloma was composed of histiocytes with a peripheral rim of benign lymphocytes which were further characterized as T-cell using immunohistochemistry for CD3 (Figure 3). Before arriving at the diagnosis, several other entities (fungal or mycobacterial infection) were ruled out with special stains including Periodic acid-Schiff (PAS) and acid fast bacilli (AFB). Because of the presence of perivascular lymphocytic cuffing, vasculitis of the central nervous system (CNS) was considered; however, it was ruled out by the absence of fibrinoid necrosis (necrosis of the vascular wall due to the inflammatory infiltrate). Another important diagnosis that needed to be ruled out was a lymphoproliferative neoplasm involving the CNS. While angiocentric lymphocytic infiltrate is a common finding in lymphomas of the CNS, the lymphocytes looked cytologically normal and flow cytometry showed no clonal lymphocytic population.