RESUMO
Waldenstrom macroglobulinemia (WM) is a low-grade B-cell lymphoma characterized by bone marrow infiltration by monoclonal lymphoplasmacytic cells plus an IgM monoclonal gammopathy. Bing-Neel syndrome (BNS) is a rare manifestation of WM where malignant lymphoplasmacytic cells infiltrate the central nervous system (CNS). Though only present in 0.8% of WM cases, it is likely underdiagnosed and may present before or during WM treatment. Here, we present a case of BNS as an initial sign of WM. A 75-year-old male presented with confusion, gait instability, and expressive aphasia. MRI demonstrated a 5.5-cm mass in the right frontal lobe, crossing midline. Brain biopsy showed CNS lymphoma and later tested positive for the MYD88L265P mutation suggesting WM (as is a mutation in 90-95% WM patients). Indeed, quantitative serum immunoglobulins showed elevated IgM. Initial treatment for WM was started with rituximab, methylprednisolone, carfilzomib, and ibrutinib. MRI two months after initiation showed good response, and the patient was transitioned to ibrutinib monotherapy. Surveillance MRI one year later showed patchy right frontal lobe enhancement indicating disease progression, and therefore the patient was placed back on his initial treatment regimen. However, ibrutinib later had to be held due to thrombocytopenia. Two months after re-starting chemotherapy, he presented with bizarre behavior, and MRI showed extensive disease progression. He was then transitioned to palliative chemotherapy with high-dose methotrexate and rituximab. He has responded well to this regimen, and MRI two years after diagnosis showed no recurrent disease. BNS is a rare but easily missed manifestation of WM. As per the recent National Comprehensive Cancer Network (NCCN) guidelines and the 8th International Workshop on WM (IWWM-8), no standardized diagnostic or management guidelines for BNS is available. Direct brain biopsy is the gold standard for diagnosis. Due to its low incidence, rarity, and limited prospective trial, there is a lack of a clear standard of care therapy. Specific treatment regimen depends on the patient factors and treatment tolerability. IWWM-8 suggests the use of a variety of cytotoxic chemotherapies or ibrutinib. A high-quality meta-analysis of existing reports is critical to characterize the diagnostic features and optimal treatment for BNS. The prognosis of BNS remains unclear, with an estimated three- and five-year survival rate at 59% and 71%, respectively. BNS is an infrequent complication of WM. Clinicians should suspect BNS with persistent, unexplained neurologic symptoms in WM.
RESUMO
The COVID-19 pandemic has underscored the shortcomings in the deployment of state-of-the-art diagnostics platforms. Although several polymerase chain reaction (PCR)-based techniques have been rapidly developed to meet the growing testing needs, such techniques often need samples collected through a swab, the use of RNA extraction kits, and expensive thermocyclers in order to successfully perform the test. Isothermal amplification-based approaches have also been recently demonstrated for rapid severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) detection by minimizing sample preparation while also reducing the instrumentation and reaction complexity. In addition, there are limited reports of saliva as the sample source, and some of these indicate inferior sensitivity when comparing reverse transcription loop-mediated isothermal amplification (RT-LAMP) with PCR-based techniques. In this paper, we demonstrate an improved sensitivity assay from saliva using a two-step RT-LAMP assay, where a short 10 min RT step is performed with only B3 and backward inner primers before the final reaction. We show that while the one-step RT-LAMP demonstrates satisfactory results, the optimized two-step approach allows detection of only few molecules per reaction and performs significantly better than the one-step RT-LAMP and conventional two-step RT-LAMP approaches with all primers included in the RT step. We show control measurements with RT-PCR, and importantly, we demonstrate RNA extraction-free RT-LAMP-based assays for detection of SARS-CoV-2 from viral transport media and saliva clinical samples.
