Primary central nervous system anaplastic large-cell lymphoma mimicking lymphomatosis cerebri

Pathological and imaging features, treatment, and prognosis of primary intraventricular lymphoma: A review of cases from a single center

Purpose

The purpose of this retrospective study was to analyze the imaging and pathological features, treatment, and prognosis of patients with primary intraventricular lymphomas (PIL) in order to enhance physicians' understanding of the diagnosis and treatment of PIL.

Methods

A retrospective analysis was conducted on 13 cases of PIL that were hospitalized in our institution. Clinical and imaging data of the patients were collected and compared with the pathology data to summarize and analyze the qualitative diagnostic value of magnetic resonance (MR) features.

Results

Among the enrolled patients, there were nine males and four females, with an average age of (56 ± 9.0) years. The major clinical features observed in PIL patients were headache and dizziness. All 13 patients underwent plain and contrast-enhanced MR scans, revealing multiple foci in 7 cases and single foci in 6 cases. The lesions were located in the lateral ventricle in 10 cases, the third ventricle in 4 cases, and the fourth ventricle in 4 cases. Plain MR scans demonstrated an isointense or slightly hypointense signal on T1-weighted imaging (T1WI) and an isointense or slightly hyperintense signal on T2-weighted imaging (T2WI). Contrast-enhanced scans showed uniform and consistent enhancement of the tumors. Surgical treatment was performed in all patients, and postoperative pathology confirmed the presence of diffuse large B-cell lymphoma.

Conclusions

PIL exhibits specific imaging and pathological features, with diffuse large B-cell lymphoma being the main pathological type. Pathological examination and immunophenotype analysis serve as the gold standards for PIL diagnosis.

Balanced transformer: efficient classification of glioblastoma and primary central nervous system lymphoma

Objective.Primary central nervous system lymphoma (PCNSL) and glioblastoma (GBM) are malignant primary brain tumors with different biological characteristics. Great differences exist between the treatment strategies of PCNSL and GBM. Thus, accurately distinguishing between PCNSL and GBM before surgery is very important for guiding neurosurgery. At present, the spinal fluid of patients is commonly extracted to find tumor markers for diagnosis. However, this method not only causes secondary injury to patients, but also easily delays treatment. Although diagnosis using radiology images is non-invasive, the morphological features and texture features of the two in magnetic resonance imaging (MRI) are quite similar, making distinction with human eyes and image diagnosis very difficult. In order to solve the problem of insufficient number of samples and sample imbalance, we used data augmentation and balanced sample sampling methods. Conventional Transformer networks use patch segmentation operations to divide images into small patches, but the lack of communication between patches leads to unbalanced data layers.Approach.To address this problem, we propose a balanced patch embedding approach that extracts high-level semantic information by reducing the feature dimensionality and maintaining the geometric variation invariance of the features. This approach balances the interactions between the information and improves the representativeness of the data. To further address the imbalance problem, the balanced patch partition method is proposed to increase the receptive field by sampling the four corners of the sliding window and introducing a linear encoding component without increasing the computational effort, and designed a new balanced loss function.Main results.Benefiting from the overall balance design, we conducted an experiment using Balanced Transformer and obtained an accuracy of 99.89%, sensitivity of 99.74%, specificity of 99.73% and AUC of 99.19%, which is far higher than the previous results (accuracy of 89.6% ∼ 96.8%, sensitivity of 74.3% ∼ 91.3%, specificity of 88.9% ∼ 96.02% and AUC of 87.8% ∼ 94.9%).Significance.This study can accurately distinguish PCNSL and GBM before surgery. Because GBM is a common type of malignant tumor, the 1% improvement in accuracy has saved many patients and reduced treatment times considerably. Thus, it can provide doctors with a good basis for auxiliary diagnosis.

Primary CNS ALK-negative anaplastic large cell lymphoma: A case report and review of the literature

Primary central nervous system (CNS) ALK-negative anaplastic large cell lymphoma (ALCL) is a rare and enigmatic disease, with limited data available in the literature. This case report adds to the existing body of knowledge by describing a unique case of a 68-year-old, immunocompetent male who presented with a single ring-enhancing lesion, which upon further analysis proved to be an ALK-negative ALCL that was primary to the CNS. A comprehensive review of the existing literature is provided, highlighting the genetic characteristics and diverse neuroimaging findings of this disease entity. This report adds valuable information to the understanding of this rare disorder, and highlights the need for further research in the field of primary CNS ALK-negative ALCL.

Clinical and imaging features of lymphomatosis cerebri: analysis of 8 cases and systematic review of the literature

Lymphomatosis cerebri (LC) is a rare type of primary central nervous system lymphoma with diffuse, nonenhancing infiltrative lesions and is often misdiagnosed. Our study aimed to investigate the clinical characteristics and prognosis of LC through analyzing patients from the literature and our own center, so as to improve early diagnosis and treatment. PubMed, Web of Science and our hospital databases were reviewed, and information on demographic, clinical, pathological, cerebrospinal fluid (CSF), neuroimaging and treatment options was extracted. Univariate survival analysis was conducted by generating survival curves and comparing them using the log-rank test. Multivariate analysis was performed using the Cox proportional hazards regression model to identify the prognostic predictors. A total of 81 patients (median age: 58 years; interquartile range, IQR: 50-66.5 years), 45 males and 36 females, were included. The most common symptoms were cognitive impairment (65.4%) and gait impairment (50.6%). Imaging studies indicated that all 81 patients had supratentorial structure involvement, and 93.8% (76/81) had bilateral hemisphere involvement. There were 53.3% (32/60) patients with CSF pleocytosis and 65% (39/60) patients with increased CSF protein levels. The median time of diagnosis was 4.8 months (IQR: 2.3-6.9 months). Compared with 4 (95% CI: 1.78-6.22) months for all 81 patients, the median OS was 20 (95% CI: 8.24-31.76) months for those who had chemotherapy plus radiotherapy. Multivariate Cox analysis revealed that chemoradiotherapy (HR: 0.12; 95% CI: 0.02-0.68) and higher CSF glucose level (HR: 0.01; 95% CI: 0.00-0.26) were inversely associated with death. The diagnosis of LC should be alerted when neuroimaging with bilateral hemispheric involvement and CSF abnormality with pleocytosis and increased protein. Once the diagnosis is confirmed, the combination of chemotherapy and radiotherapy can be considered if the patient's physical condition permits.Journal standard instruction requires an unstructured abstract. Kindly check and confirm.We have checked and confirmed that there is no problem.

ALK-negative CNS anaplastic large cell lymphoma: case report and review of literature

BACKGROUND

Central nervous system (CNS) lymphomas frequently pose a diagnostic challenge to physicians. CNS anaplastic large cell lymphoma (ALCL) is a rare condition. A majority (80%) of ALCLs harbour anaplastic lymphoma kinase 1 (ALK-1) mutation with only a minority testing negative for this mutation.

METHODS

Here we report a rare case of ALK-negative CNS ALCL with dural involvement. We conducted a literature search using PubMed for published studies in English on cases of patients with ALCL of the brain. The keywords used were 'anaplastic large cell lymphoma', 'ALK' and 'primary central nervous system lymphoma'.

RESULTS

A 63-year-old man presents with waxing and waning cranial nerve and spinal cord symptoms. MRI revealed multiple intracranial and intra-spinal lesions that were highly steroid responsive. A wide range of serum and CSF tests were non-diagnostic during three months of workup before a lesion appeared in the cervical spine that required decompression and allowed us to obtain a tissue sample. Final pathology revealed ALK-negative ALCL. There are only 24 reported adult cases to date of CNS ALCL in the English literature. To our knowledge, this is the first case of ALK-negative ALCL with primarily CNS and meningeal involvement.

CONCLUSIONS

ALK-negative ALCL with CNS involvement is extremely rare, which frequently results in delayed diagnosis (average 40.5 days). The diagnostic challenge posed by this case highlights the importance of a team approach to workup and diligent patient follow-up for such a rare disease.

Central nervous system ALK-negative anaplastic large cell lymphoma with IRF4/DUSP22 rearrangement

Anaplastic large cell lymphomas (ALCL) are mature T-cell neoplasms, approximately half of which harbor rearrangements of the ALK gene that confer a good prognosis. Recent studies have demonstrated that a significant proportion of ALK-negative ALCLs demonstrate rearrangements of the IRF4/DUSP22 locus that also are typically associated with a favorable prognosis. ALCL with primary involvement of the central nervous system (CNS) is extremely rare. We report what may be the first case of ALK-negative ALCL with IRF4/DUSP22 rearrangement involving the brain in a 55-year-old man. Magnetic resonance imaging demonstrated signal abnormalities in the periventricular region, corpus callosum and cingulate gyrus. Biopsy revealed a diffuse parenchymal and angiocentric infiltrate of CD30-positive cells that showed IRF4/DUSP22 rearrangement by fluorescence in situ hybridization. We also review the clinical and pathologic features of primary CNS ALK-negative ALCLs in the literature and highlight the need for awareness of this entity to optimize appropriate management.

Clinical Features and Prognostic Factors for Primary Anaplastic Large Cell Lymphoma of the Central Nervous System: A Systematic Review

Simple Summary

Primary anaplastic large cell lymphoma (ALCL) of the central nervous system (CNS) is a subtype of primary central nervous system lymphoma (PCNSL). ALCL is divided into anaplastic lymphoma kinase (ALK)-positive ALCL and ALK-negative ALCL, according to ALK expression. ALK-positive cancers tend to develop at a younger age and tend to have a better prognosis. Almost all past articles on primary ALCL of the CNS have been case reports and there have been no randomized trials or cohort studies on this subject. We thus performed a systematic review of primary ALCL of the CNS. According to the author’s survey, 36 case reports have been published in English-language journals. In this paper, we have summarized the clinical features and prognostic factors for primary ALCL of the CNS based on previous studies.

Abstract

Primary anaplastic large cell lymphoma (ALCL) of the central nervous system (CNS) is a subtype of primary CNS lymphoma (PCNSL). There are very few comprehensive reports on this extremely rare tumor. Therefore, it is necessary to investigate the clinical features and prognostic factors for primary ALCL of the CNS. We performed a systematic review of the published literature. Past cases were comprehensively searched using PubMed, Cochrane Library, and Web of Science. Clinical information, such as age, sex, anaplastic lymphoma kinase (ALK) status, lesion sites, treatment methods, and survivorship were extracted. Thirty-nine cases with information on ALK status and treatment course were identified. The average observation period was 13 months, and the overall 2-year survival rate was 58%. Univariate analyses showed a statistically significantly better prognosis among patients < 40 years of age (p = 0.039, HR 0.32 (0.11–0.95)) and in relation to ALK positivity (p = 0.010, HR 0.24 (0.08–0.71) and methotrexate treatment (p = 0.003, HR 0.17 (0.05–0.56)). Because of the sparsity of cases, it is necessary to accumulate cases in order to perform more detailed analyses.

Case Report: Paraneoplastic Hashimoto's Encephalopathy Associated With Lymphomatosis Cerebri With Periodic Synchronous Discharges Resembling Creutzfeldt-Jakob Disease

Hashimoto's encephalopathy (HE) is an autoimmune encephalopathy that presents with various clinical symptoms, including cognitive deterioration, convulsive seizures, and personality changes. HE is associated with thyroid autoimmunity; however, few cases have been reported to develop as paraneoplastic syndrome. Herein, we report the case of a 73-year-old woman with onset of rapidly progressive dementia. Brain magnetic resonance imaging showed diffuse T2 hyperintensity areas involving the bilateral cerebral white matter, right midbrain tegmental area, left cerebral peduncle, and right middle cerebellar peduncle without clear diffusion hyperintensities and gadolinium enhancement. Her neurological symptoms worsened rapidly, and she presented with the apallic syndrome. Electroencephalogram showed periodic synchronous discharge, suggestive of Creutzfeldt–Jakob disease. However, a brain biopsy revealed infiltration of atypical lymphoid cells expressing CD20, and the anti-NH2 terminal of the α-enolase antibody was detected, diagnosing the complication with lymphomatosis cerebri and HE. High-dose intravenous methylprednisolone therapy and oral prednisolone with whole cranial irradiation enabled her to have simple conversations and consume food orally; however, severe cognitive impairment persisted. Although HE is a rare complication of malignant lymphoma, clinicians should be aware that it could be strongly suspected if the clinical symptoms worsen in the absence of imaging changes.

"Slow and Steady" Infiltrates the Brain: An Autopsy Report of Lymphomatosis Cerebri

Primary central nervous system lymphomas (PCNSL) usually present as single or multiple lesions with mass effect involving the cerebral hemispheres or basal ganglia. An extremely rare pattern of involvement termed "Lymphomatosis cerebri" (LC) presents as diffuse, non-enhancing infiltrative lesions without mass effect. We describe the clinical, radiological, and autopsy findings of one such rare example with a patient presenting with a short history of fever, memory loss, and progressive cognitive decline. Because of subtle yet rapidly progressive clinical symptoms and overlapping neuroimaging features, the diagnosis of LC is challenging with wide ranging differential diagnoses. The dilemma in diagnosing such lesions can lead to delay in diagnosis and institution of appropriate management. Thus, knowledge about its imaging and morphological features is very critical for correct categorization and to avoid potential misdiagnosis of this often-missed disease.

Diffuse large B-cell lymphoma of the central nervous system presenting as "lymphomatosis cerebri" and dementia in elderly man: Case report and review of the literature

RATIONALE

Lymphomatosis cerebri is a rare form of PCNSL, characterized by diffuse infiltration of lymphoma cells in cerebral parenchyma, without mass-formation and mild or no contrast enhancement on magnetic resonance (MR) imaging. There are less than 50 cases described in the literature under the term Lymphomatosis cerebri.

PATIENT CONCERNS

A 74-year-old man presented to our service with progressive dementia for 12 months and accelerated cognitive decline within the last two months. Brain magnetic resonance imaging showed areas of hyperintensity involving predominantly the white matter of frontal lobes and knee of the corpus callosum, along with areas of blood-brain barrier disruption and areas of restricted diffusion. Stereotaxy brain surgery was indicated into contrasting areas and histologically there was heterogeneous foci of discreet infiltration of rare medium-large lymphoid cells intermingled with inflammatory cells and these atypical lymphoid cells were placed on breakdown neuropil and did not form tumor mass or sheets of cells, but occasionally displayed perivascular distribution. Immunohistochemically, these atypical lymphoid cells expressed CD20, Bcl2, Bcl6 and, heterogeneously, IRF4/MUM1.

DIAGNOSIS

The diagnosis of a primary CNS diffuse large B-cell lymphoma manifested as lymphomatosis cerebri was performed.

INTERVENTIONS

The treatment of choice was: temozolomide 100 mg/m (D1 to D5), methotrexate 3 g/m (D1, D10, and D20) and rituximab 375 mg/m.

OUTCOMES

The patient evolved with progressive neurological deterioration, regardless of the improvement on neuroimaging.

LESSONS

We described the diagnostic dilemma we faced with an elderly man with rapid cognitive impairment and a myriad of differential diagnoses, diagnosed with primary CNS diffuse large B-cell lymphoma with a lymphomatosis cerebri-like pattern.

Neuroradiological features of lymphomatosis cerebri: A systematic review of the English literature with a new case report

Lymphomatosis cerebri is a rare form of diffusely infiltrating primary central nervous system (CNS) lymphoma (PCNSL). The neuroradiological findings of lymphomatosis cerebri have not been adequately characterized, as the relevant literature consists only of case reports and small case series. The present study describes an unusual presentation of lymphomatosis cerebri in a 56-year-old immunocompetent woman who presented with diffusely infiltrating lesions with perivascular curvilinear enhancement on initial magnetic resonance imaging (MRI) and multiple nodules on the later follow-up computed tomography (CT) scan. A systematic review of the literature is also performed searching PubMed between January 1996 and December 2016 to collect all pertinent case reports and series written in the English language with pathologically confirmed lymphomatosis cerebri and diffuse infiltrative PCNSL without cohesive masses on initial MRI. A total of 45 cases were identified from 39 articles and the present case report. The patient ages ranged from 28 to 85 years (mean, 57.3 years). Only 3 patients (6.7%) were immunosuppressed (acquired immune deficiency syndrome patients). The most common clinical presentation was cognitive changes or dementia (46.7%). Cerebrospinal fluid analysis in all cases was non-specific. Diffuse and asymmetric abnormal T2-hyperintensity in deep and subcortical white matter was observed in all cases. Gray matter involvement (17.8%), spreading along the corticospinal tract (35.6%) and a slight mass effect (51.1%) also were observed. Contrast-enhanced patterns on MRI could be divided into three forms of non-enhancement (64.4%) and non-mass-like enhancement (35.6%) on initial MRI, as well as nodular or mass-like enhancement on the later follow-up MRI (15.6%). There were non-specific findings on magnetic resonance spectroscopy for 4 patients, on positron emission tomography/CT for 12 patients and on single-photon emission CT for 1 patient. Diagnosis was established by brain biopsy in 35 cases (77.8%) and autopsy in 9 cases (20%), involving B-cell lymphoma in 40 cases (88.9%) and T-cell lymphoma in 4 cases (8.9%). In conclusion, lymphomatosis cerebri, namely diffuse PCNSL or diffuse lymphoma of the CNS, is characterized by rapidly progressive dementia in the elderly, diffusely infiltrated CNS white matter along the corticospinal tract, possible involvement of the gray matter, a slight mass effect and varied contrast-enhancement patterns on MRI. Non-enhancement or non-mass-like enhancement on MRI may be a special form of diffuse PCNL during disease development and progression.

Lymphomatosis cerebri: a rare variant of primary central nervous system lymphoma and MR imaging features

BACKGROUND

Lymphomatosis cerebri (LC) is a rare variant of primary central nervous system lymphoma (PCNSL), characterized by diffuse infiltration without the formation of a discrete mass. The diagnosis of LC is a challenge because the imaging findings are atypical for lymphoma. The purpose of present study is to investigate MRI characteristics and clinical features of LC and potentially facilitate an early and accurate diagnosis of this often-missed disease.

METHODS

Seven patients (average 44 years, 19-58 years) with LC proved basing on MRI and histology were retrospectively reviewed the clinical data and cerebral MR imaging findings.

RESULTS

The common presenting symptoms were cognitive decline, behavioral disturbance, gait disturbance. All patients had both deep and lobar lesion distribution, and two of them had infratentorial involvement. Lack of contrast enhancement and subtle patchy enhanced pattern were observed in two and three patients, respectively. The remaining two patients presented multiple patchy enhancement. Most of the lesions were slightly hyperintense to normal brain on DWI as well as hyperintense on ADC maps. Three patients presented a pattern of marked decrease of NAA/Cr, increase of Cho/Cr, and two of the three cases showed increased Lip/Cr and Lac/Cr on MRS.

CONCLUSIONS

We conclude that diffuse bilateral lesions especially in deep and lobar region including white and gray matter, without enhancement or with patchy enhancement, marked decrease of NAA/Cr and increase of Cho/Cr, and increased Lip/Cr and Lac/Cr are suggestive of LC. Prompt recognition of these imaging patterns may lead to early diagnosis of LC and brain biopsy with improved prognosis.

Primary CNS T-cell Lymphomas: A Clinical, Morphologic, Immunophenotypic, and Molecular Analysis

Primary central nervous system (CNS) lymphomas are relatively rare with the most common subtype being diffuse large B-cell lymphoma. Primary CNS T-cell lymphomas (PCNSTL) account for <5% of CNS lymphomas. We report the clinical, morphologic, immunophenotypic, and molecular characteristics of 18 PCNSTLs. Fifteen cases were classified as peripheral T-cell lymphoma, not otherwise specified, 2 of which were of γδ T-cell derivation and 1 was TCR silent; there was 1 anaplastic large cell lymphoma, ALK-positive and 2 anaplastic large cell lymphoma, ALK-negative. Median age was 58.5 years (range, 21 to 81 y), with an M:F ratio of 11:7. Imaging results showed that 15 patients had supratentorial lesions. Regardless of subtype, necrosis and perivascular cuffing of tumor cells were frequently observed (11/18 cases). CD3 was positive in all cases but 1; 10/17 were CD8-positive, and 5/17 were CD4-positive. Most cases studied had a cytotoxic phenotype with expression of TIA1 (13/15) and granzyme-B (9/13). Polymerase chain reaction analysis of T-cell receptor γ rearrangement confirmed a T-cell clone in 14 cases with adequate DNA quality. Next-generation sequencing showed somatic mutations in 36% of cases studied; 2 had >1 mutation, and none showed overlapping mutations. These included mutations in DNMT3A, KRAS, JAK3, STAT3, STAT5B, GNB1, and TET2 genes, genes implicated previously in other T-cell neoplasms. The outcome was heterogenous; 2 patients are alive without disease, 4 are alive with disease, and 6 died of disease. In conclusion, PCNSTLs are histologically and genomically heterogenous with frequent phenotypic aberrancy and a cytotoxic phenotype in most cases.

Lymphomatosis cerebri: a rare form of primary central nervous system lymphoma. Analysis of 7 cases and systematic review of the literature

BACKGROUND

Primary central nervous system lymphomas may present as diffuse, nonenhancing infiltrative lesions. This rare variant is termed lymphomatosis cerebri (LC). We did a systematic review and analysis of the literature, adding our own cases, to better characterize LC in order to improve early diagnosis and treatment.

METHODS

PubMed, ISI Web of Knowledge, and hospital databases were reviewed. Information was extracted regarding demographic, clinical, histological, cerebrospinal fluid (CSF), neuroimaging, and treatment variables. The impact of single parameters on overall survival (OS) was determined by applying univariate and multivariate analyses.

RESULTS

Forty-two patients were included (median age: 58 y; range: 28-80 y). At consultation, 52% of patients had a poor KPS. The most common presenting symptom was cognitive decline (59.5%). Imaging studies showed supratentorial and infratentorial infiltration in 55% of patients and bilateral hemispheric involvement in 95%. CSF pleocytosis was present in 51.5% of the patients. Median time to diagnosis was 4.5 (range: 1-30) months, and the diagnosis was not established until autopsy for 33% of patients. The median OS was 2.95 (range: 0.33-56) months; however, those patients who received methotrexate had a median OS of 13.8 (range: 0.7-56) months. Analysis identified KPS ≥ 70 (HR: 0.32; 95% CI: 0.114-0.894; P = .03) and treatment with methotrexate (HR: 0.19; 95% CI: 0.041-0.886; P = .034) as independent favorable prognostic factors, whereas T-cell lymphoma was independently related with a worse outcome (HR: 6.62; 95% CI: 1.317-33.316; P = .022).

CONCLUSIONS

LC is a misdiagnosed entity associated with considerable diagnostic delay. MRI evidence of bilateral hemispheric involvement and CSF pleocytosis should be alerts for this diagnosis. Treatment with methotrexate-based chemotherapy must be considered, especially for patients with good KPS.

Neurocognitive features distinguishing primary central nervous system lymphoma from other possible causes of rapidly progressive dementia

OBJECTIVE

Define the neurocognitive features of primary central nervous system lymphoma (PCNSL) presenting with dementia, and compare with other causes of rapidly progressive dementia (RPD).

BACKGROUND

PCNSL can present as an RPD. Differentiating PCNSL from other RPDs is critical because lymphomatous dementia may be reversible, and untreated PCNSL is fatal.

METHODS

We performed a meta-analysis of case reports of dementia from PCNSL (between 1950 and 2013); 20 patients (14 with lymphomatosis cerebri) met our criteria. We compared these patients to a case series of patients with RPD from Creutzfeldt-Jakob disease and other non-PCNSL etiologies (Sala et al, 2012. Alzheimer Dis Assoc Disord. 26:267-271).

RESULTS

Median age was 66 years (range 41 to 81); 70% were men. Time from symptom onset to evaluation was <6 months in 65%. No patients had seizures; 5% had headaches; 45% had non-aphasic speech difficulty. There was significantly more memory impairment in patients with PCNSL than other RPDs and significantly less myoclonus and parkinsonism. Behavioral changes and cerebellar signs were not significantly different. Significantly more patients with PCNSL than other RPDs had white matter changes; significantly fewer had atrophy. Elevated CSF protein and pleocytosis were more frequent in PCNSL; patients with other RPDs tended to have normal CSF±14-3-3 protein.

CONCLUSIONS

Unlike patients with RPD from other causes, those with PCNSL commonly present with impaired memory, apathy, and abnormal speech and gait, without headache, seizure, or myoclonus. White matter changes and CSF abnormalities predominate. Improved clinical awareness of PCNSL can prompt earlier diagnosis and treatment.

Clinical presentation of anaplastic large-cell lymphoma in the central nervous system

The majority of primary central nervous system (CNS) lymphomas are diffuse large B-cell lymphomas (DLBCLs) and anaplastic large-cell lymphoma (ALCL) is a type of T-cell tumor that is rare in the CNS. The aim of this study was to elucidate the clinical presentation and standard therapy of ALCLs by investigating reported cases. Additionally, a case of anaplastic lymphoma kinase (ALK)-positive ALCL in a 20-year-old man who exhibited no recurrence for >5 years following high-dose methotrexate (HD-MTX) treatment was described. Twenty-six immunocompetent patients with ALCL of the CNS that were previously reported and 1 case of ALCL of the CNS treated at our hospital were investigated. Overall survival (OS) was analyzed in relation to survival factors such as age, ALK status and the treatment regimen. The male:female ratio of the patients was 19:8. Of the 27 patients, 13 (48.1%) were ALK-positive, 9 (33.3%) were ALK-negative and the ALK status was not determined in the remaining 5 patients (18.5%). ALK-positive ALCL occurred at a younger age (median age, 17 years) and exhibited a favorable course (5-year OS, 75.0%), whereas ALK-negative ALCL presented at an older age (median age, 65 years) and resulted in fatal outcomes (5-year OS, <12.5%). Similar to the findings for systemic ALCL, ALK positivity, age <40 years and chemotherapy are associated with long-term survival for ALCL of the CNS. Chemoradiotherapy including methotrexate is recommended for ALCL and the possibility of treatment with chemotherapy alone for ALK-positive ALCL is currently under consideration.