The utility of proton MR spectroscopy in diagnosing B cell lymphoma.

Abstract

e13536 Background: Diffuse Large B Cell Lymphoma (DLBCL) is the most common and increasingly prevalent subtype of Non-Hodgkin lymphoma in both immunocompromised and immunocompetent patients. Its pathogenesis is thought to represent rearrangements, translocations, and transformations of both the immunoglobulin heavy and light chain genes along with somatic mutations of the variable regions of these same genes. A 66-year old Caucasian male with a past medical history of smoking presented to the hospital due to concerns of mental status change, flat affect, and fronto-orbital headache for one-week duration. The patient denied any drug or substance abuse. Physical exam was diffusely normal with the exception of flat affect. Methods: Magnetic resonance spectroscopy is a noninvasive, non-ionizing diagnostic analytical technique that has been used to measure metabolic changes in brain lesions. Results: Lhermitte’s sign was negative and NIH stroke scale was calculated to be 0. CT demonstrated a 17mm frontal lobe lesion. Follow up with MRI showed three bilateral enhancing brain lesions, but no metastasis or primary tumor was seen via CT of chest, abdomen, and pelvis. Initial differential diagnosis included: Tumefactive Multiple Sclerosis, Acute Demyelinating Encephalomyelitis or CNS lymphoma. EEG did not highlight any focal or epileptiform abnormalities and lumbar puncture was negative for Creutzfeld Jacob Disease and Multiple Sclerosis. The patient was discharged with a course of intravenous steroids only to present a few weeks later with no improvement of symptoms. The patient then had proton magnetic resonance spectroscopy (MRS). MRS pattern spikes and chemical profile suggested lymphoma, which was confirmed by a brain biopsy. The patient was subsequently transferred to the University of Pennsylvania for treatment and further management. Conclusions: This case illustrates the beneficial use of MRS, as data patterns it provides compliments the clinician’s knowledge to proceed with appropriate treatment.