Primary lymphomas of the central nervous system (PCNSL) are highly aggressive tumors affecting exclusively the CNS, meninges, and eyes. PCNSL must be separated from secondary spread of systemic lymphoma to the CNS (SCNSL), which may occur at diagnosis or relapse of systemic lymphomas. At present, there are no valid methods to distinguish PCNSL from SCNSL based on tumor biopsy because of similar histological presentation. However, SCNSL and PCNSL are different in terms of prognosis and adequate therapy protocols. MicroRNA expression profiles of CSF samples collected from SCNSL and PCNSL patients were compared using microRNA arrays. MiR-30c revealed the largest differential expression and was selected for validation by RT-PCR on 61 CSF samples from patients with PCNSL and 14 samples from SCNSL. MiR-30c was significantly increased in patients with SCNSL compared to PCNSL (p < 0.001). MiR-30c levels in CSF enabled the differentiation of patients with PCNSL from SCNSL with an area under the curve (AUC) of 0.86, with a sensitivity of 90.9% and a specificity of 85.5%. Our data suggest that miR-30c detected in the CSF can serve as biomarker for distinction between PCNSL and SCNSL. The validation in a larger cohort is needed. With respect to its function, miR-30c may facilitate lymphoma cells to engraft into CNS by interaction with CELSR3 gene that controls the function of ependymal cilia and, thus, affects the circulation of CSF.

Background In patients with presumed primary CNS lymphoma (PCNSL) a systemic manifestation is found only in a small minority. Although bone marrow biopsy (BMB) is recommended for staging, its diagnostic value is unclear. Methods A retrospective analysis of 392 patients with presumed PCNSL from three university hospitals and 33 patients with secondary CNS lymphoma (SCNSL) and initial CNS involvement from a multicentre Germany-wide prospective registry was performed. Results A BMB was performed and documented in 320/392 patients with presumed PCNSL; 23 had pathologic results. One harboured the same lymphoma in the brain and bone marrow (BM), 22 showed findings in BM discordant to the histology of brain lymphoma; n=12 harboured a low grade lymphoma in the bone marrow, the other showed B-cell proliferation but no proof of lymphoma (n=5), monoclonal B-cells (n=3) or abnormalities not B-cell associated (n=2). In the group of SCNSL with initial CNS manifestation 32/33 patients underwent BMB; seven were documented with bone marrow involvement (BMI); one had concordant results in the brain and bone marrow with no other systemic manifestation. Six had additional systemic lymphoma manifestations apart from the brain and bone marrow. Conclusions In only two out of 352 (0.6%) patients with CNS lymphoma (320 presumed PCNSL and 32 SCNSL) BMB had an impact on diagnosis and treatment. While collected in a selected cohort these findings challenge the value of BMB as part of routine staging in presumed PCNSL.

Background: To evaluate outcome and toxicity of High-dose methotrexate (HDMTX)-based induction therapy followed by consolidation with conventional systemic chemotherapy and facultative intraventricular therapy (modified Bonn protocol) in patients with primary CNS lymphoma (PCNSL).Methods: Between 01/2005 and 12/2013 113 patients with newly diagnosed PCNSL presented at our center; 98 of those qualified for HDMTX based chemotherapy, received a modified Bonn protocol and were included in the analysis. The treatment regimen was based on the "Bonn protocol", but modified by omission of systemic drugs not able to cross the intact blood brain barrier. Intraventricular therapy was postponed until completion of three induction chemotherapy cycles or was replaced by intrathecal liposomal AraC and rituximab was added to induction from 2010 onwards.Results: Median patient age was 67 years (range 38-83). Complete response/complete response unconfirmed (CR/CRu) was achieved in 59/98 patients (60%), partial response (PR) in 9/98 patients (9%). Twenty-four patients (23%) had progressive disease (PD), 6 (6%) died on therapy. Median progression-free survival (PFS) for all patients was 11.4 months, median overall survival (OS) 29.1 months. A trend to better outcome for intraventricular therapy versus intrathecal liposomal AraC was found in patients < 65 years ] for OS and 0.46 [0.21-1.02] for PFS. Ommaya reservoir infection occurred in 3/33 patients (9%). Conclusions:The data of this single center experience suggest that the outcome with a modified Bonn protocol was comparable to that of the previous regimen, showed fewer Ommaya reservoir infections and may have a trend for better outcome with intraventricular therapy.

Background: To investigate outcome and toxicity of high-dose systemic methotrexate (HDMTX)-based polychemotherapy and intracerebroventricular (ICV) chemotherapy via an Ommaya reservoir in elderly patients with primary central nervous system lymphoma (PCNSL). Methods: We performed a retrospective analysis on patients ⩾65 years with first diagnosis of PCNSL admitted to our center between January 2015 and December 2019. These patients were treated with a standardized chemotherapy protocol in case of absent contraindications for HDMTX-based chemotherapy. The protocol contained induction therapy with systemic rituximab, methotrexate and ifosfamide and consolidation treatment with systemic cytarabine (AraC) and ICV methotrexate, prednisolone and AraC. Results: Of a total of 46 patients seen in this period, 3 did not qualify for HDMTX. Thus, 43 patients were included in this analysis. Median age was 74 years (range 65–86), median Karnofsky performance score was 50 (range 20–90). Of the 43 patients, 32 (74.4%) completed treatment including ICV therapy. Complete remission/complete remission unconfirmed was achieved in 26 of 43 patients (60.5%), partial response (PR) in 3 (7%); 5 (11.6%) had progressive disease, and 3 (7.0%) died due to treatment-related complications; in the remaining 6 (14.0%) therapy could not be completed. Median progression free survival was 16 months (95% confidence interval 8–24 months) and median overall survival had not been reached after a median follow up of 23 months (range 1–52 months); the 75th percentile survival time was 12 months. No Ommaya reservoir infection was observed. Complications of ICV treatment were pericatheter leucencephalopathy in two patients and surgical scar dehiscence with cerebrospinal fluid leak in one patient. Conclusion: Toxicity of HDMTX plus ICV chemotherapy for elderly patients with PCNSL was manageable and outcome was excellent for patients treated with this protocol.

The implantation of a subgaleal reservoir intracerebroventricular (ICV port) in order to apply ICV chemotherapy in patients with leptomeningeal cancer may be complicated by misplacement of the device, pericatheter leucencephalopathy, hemorrhage and iatrogenic ventriculitis/meningitis. Here we analyzed the occurrence of such complications in patients with primary central nervous system lymphoma (PCNSL) treated with systemic and ICV methotrexate‐ and cytarabine‐based chemotherapy. We retrospectively reviewed the medical records of 94 consecutive patients (1247 installations), who had received an ICV port for intraventricular chemotherapy for treatment of histologically confirmed PCNSL at our institution between September 2005 and October 2018. Infectious and noninfectious complications were systematically recorded including clinical, laboratory, and imaging data. In 9/94 patients (9.6%), a misplacement of the ICV port seen on the postoperative computed tomography scan was corrected immediately and chemotherapy was then continued as planned. In 5/94 patients (5.3%), symptomatic noninfectious complications were observed (four patients with symptomatic pericatheter leucencephalopathy and one patient with surgical scar dehiscence with CSF leak). In 8/94 patients (8.5%), asymptomatic white matter lesions around the catheter were visible on cerebral magnetic resonance imaging after completion of therapy. The rate of infectious complications was 6/94 patients (6.4%). No complication was lethal or required intensive care monitoring. This retrospective study shows that complications of ICV treatment have to be expected in a fraction of patients, however, in this series these complications were manageable and did not result in long‐term deficits.