Tissue pathology of a mass is often the gold standard for diagnosis of a malignancy. The dilemma is when the lesion is central and a biopsy cannot be safely obtained. The diagnostic burden is then placed on laboratory and imaging, which can be misleading and cause grave consequences. This case is about a 46-year-old male whose initial impression and final pathology results were conflicting and led to a delay in treatment.
A 46-year-old male presented with 6-month history of vomiting, weight loss and diplopia. An MRI of the brain was obtained for further evaluation and showed multifocal areas of parenchymal enhancement. Lesions were noted in the median eminence, dorsal medulla, right lateral fourth ventricular wall and posterior septum pellucidum. Lumbar puncture studies showed elevated protein and WBCs with lymphocytosis. Oligoclonal bands and IgG index were elevated although cytology results were negative. Infectious processes were ruled out, including HIV and other infiltrative processes. CT and Gallium scans were performed and were negative for malignant lesions and peripheral sites for potential biopsy. The patient and family declined biopsy due to the fear of the risks of neurosurgery. With the available data, the patient was diagnosed with possible neurosarcoidosis. Treatment with high dose steroids showed a significant improvement clinically and on repeat MRI. Once steroid tapering was initiated the patient’s health declined and new brain lesions appeared. Biopsy of one of the newer lesions was obtained and showed primary CNS lymphoma with immunoreactivity to CD20. Treatment was then initiated with high dose methotrexate and Rituxan. Though appropriate treatment was started, patient’s health continued to rapidly decline. Less than twelve months since the initial onset of symptoms the patient was referred to hospice for comfort care.
The diagnosis of primary CNS lymphomas, although rare, has been increasing over the past few years. In CNS lymphomas, the time to diagnosis and treatment largely affects the overall survival time. Currently there are no guidelines for evaluation and diagnosis of multiple brain lesions if proper tissue diagnosis cannot be obtained. The diagnosis of possible neurosarcoidosis was made with evidence of CNS inflammation on MRI with compatible CSF studies. In our case, further testing with immunohistochemistry could have improved diagnostic yield for primary CNS lymphoma, as basic CSF cytology has a high false-negative rate. With structured diagnostic guidelines the delay in diagnosis may have been avoided and likely improved overall morbidity and mortality. Identification and discussion of such patients will allow us to broaden our work-up and likely lead to more rapid treatment and better patient outcomes.