B cell-rich non-neoplastic sentinel lesion preceding primary central nervous system lymphoma

Usefulness and pitfalls of neuroendoscopic tumor biopsy for intracranial malignant lymphoma

PURPOSE

Neuroendoscopic biopsy has various advantages, such as being able to collect larger tissue samples and achieving more efficient hemostasis compared to needle biopsy. The purpose of this study is to review the surgical techniques, accuracy of pathological diagnosis, and perioperative complications of patients with intracerebral malignant lymphoma who were diagnosed mainly by neuroendoscopic biopsy.

METHODS

A total of 65 patients diagnosed as having malignant lymphoma, via mainly neuroendoscopic biopsy, were analyzed retrospectively. A flexible neuroendoscope was used for ventricular and paraventricular lesions, which was inserted via the lateral ventricle. For intraparenchymal lesions, rigid scopes with navigation systems were used.

RESULTS

The main location of the tumors was in the intraventricular/paraventricular regions in 22 patients, in the deep white matter in 22 patients, in the basal ganglia in 14 patients, and in the cerebellum in 5 patients. Two patients had a lymphomatosis cerebri-like lesion. Lymphoma was diagnosed in 58 of the 65 patients, with most patients diagnosed as having diffuse large B-cell lymphoma. Incorrect diagnoses were owing to inappropriate samples, sentinel lesions, or preoperative treatments, such as with steroids. Complications included small cerebral hematoma in 5 patients, severe cerebral edema in 3 patients (2 fatal), and brain abscess and arterial bleeding leading to infarction in 1 case each.

CONCLUSION

Neuroendoscopic biopsy is a reliable diagnostic approach for intracranial malignant lymphomas, particularly those in deep or intraventricular/paraventricular locations. However, caution is particularly required for patients with severe cerebral swelling, which may cause death, and those with prior sentinel lesions.

Could Cerebral Inflammatory Lesions be the Cellular Origin of Primary Central Nervous System Lymphoma?

INTRODUCTION

Primary central nervous system lymphoma (PCNSL) presents a diagnostic enigma due to the inherent absence of lymphoid tissue in the central nervous system (CNS). The hypothesis posits that lymphocytes infiltrating the CNS during inflammatory responses could represent a cellular source for PCNSL, challenging traditional understandings of its etiology.

PATIENT CONCERNS

In 2 illustrative cases, patients presented with neurological symptoms initially misdiagnosed as encephalitis and demyelinating disease, respectively. These diagnoses were established based on clinical assessments and initial biopsy findings.

DIAGNOSIS

Subsequent biopsies, conducted months after the first signs of disease, confirmed the diagnosis of PCNSL in both patients. Identifying CD20-positive tumor cells was pivotal, indicating a B-cell lymphoma origin.

INTERVENTIONS

Treatment strategies included high-dose methotrexate chemotherapy for both patients. In addition, the second patient underwent adjuvant whole-brain radiotherapy after the chemotherapy regimen.

OUTCOMES

The therapeutic approach significantly reduced tumor size in both cases, with no evidence of recurrence observed during the follow-up period. This outcome underscores the potential efficacy of the chosen interventions.

CONCLUSION

In response to inflammatory lesions, lymphocyte infiltration into the CNS may serve as a pivotal origin for tumor cells in PCNSL. These cases highlight the complexity of diagnosing CNS disorders and suggest that various forms of encephalitis in the early stages could influence the prognosis of lymphoma. This insight into the cellular origins and treatment responses of PCNSL contributes to a broader understanding of its pathophysiology and management.

Myelin oligodendrocyte glycoprotein antibody-associated disease preceding primary central nervous system lymphoma: causality or coincidence?

INTRODUCTION

Primary central nervous system lymphoma (PCNSL) is a rare extranodal lymphomatous malignancy that affects the brain, spinal cord, leptomeninges, or eyes, in the absence of systemic diffusion. Myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD) is a newly identified benign immune-mediated CNS inflammatory disorder with specific anti-MOG antibody seropositivity. These two seemingly unrelated nosological entities both have abundant clinical and radiological manifestations, and whether there is a potential link between them is unclear.

CASE REPORT

We describe a 49-year-old man who presented progressive headache, dizziness, and unsteady gait with multifocal scattered T2 hyperintensities with contrast enhancement. The serum anti-MOG antibody test was positive, and a brain biopsy showed inflammatory infiltration. Initially, he was diagnosed with MOGAD and his condition improved after corticosteroid therapy. The patient relapsed with exacerbation of symptoms and neuroimaging showed new mass-forming lesions four months later. A second brain biopsy confirmed PCNSL.

DISCUSSION

This is the first report of histologically confirmed successive MOGAD and PCNSL. Our case broadens the phenotypic spectrum of sentinel lesions in PCNSL. Though rare, PCNSL should be considered in patients diagnosed with benign CNS inflammatory disorder and responding well to steroid treatment when their clinical symptoms worsen and the imaging deteriorates. A timely biopsy is critical for accurate diagnosis and appropriate therapy.

Neuroinflammation preceding primary central nervous system lymphoma (PCNSL) - Case reports and literature review

Primary central nervous system lymphoma (PCNSL) is a rare and aggressive form of extra-nodal non-Hodgkin's lymphoma. Corticosteroids cause transient regression of PCNSL at the radiological and histological level. A growing number of case reports describe histologically confirmed neuroinflammation (sentinel lesions) heralding the development of PCNSL. We present two further cases of sentinel lesions contextualised by a review of past literature. Our aims are to collate existing knowledge on sentinel lesions in PCNSL and explore their pathophysiological significance. Two cases were identified (n = 2) from a cohort of 104 patients with PCNSL referred to a tertiary neurosurgery centre. A literature search identified previously reported cases (n = 14). Median age was 57.5 (range; 26-72); pre-biopsy corticosteroid administration was reported in 50% of cases (n = 8); mean time between biopsies was 10 months (range; 3-60). Common MRI features were homogenous enhancement (10;71.4%) and T2-hyperintensity (11;100%). Histochemical analysis of sentinel lesion biopsy revealed inflammatory CD3/4/5/8-positive T-cells (14; 100%), demyelination (13; 81.3%), rare/scattered CD20-postive B-cells (11;78.6%) and CD68-positive macrophages (10;71.4%). Repeat biopsy confirmed PCNSL in all cases. Waxing and waning CNS inflammation has been identified in 16 patients ultimately diagnosed with PCNSL. Neuro-specialists should be aware of this atypical presentation and maintain a high index of suspicion for lymphoma despite histopathology negative for lymphoma when clinical or radiological features indicate PCNSL.

Histopathological variation in the demyelinating sentinel lesion of primary central nervous system lymphoma

Background:

Primary central nervous system lymphoma (PCNSL) is one of the least common malignant brain tumors. It is usually diagnosed initially as diffuse large B cell lymphoma (DLBCL). In rare cases, however, a demyelinating lesion referred to as a “sentinel lesion” precedes the actual diagnosis, which usually depicts two distinct patterns of inflammatory cells during histological analysis. This case report describes a unique histological finding and describes the recognized variations in sentinel lesion histopathology.

Case Description:

A 78-year-old female patient was found to have multiple white matter lesions of various degrees of enhancement on post-contrast T1-weighted magnetic resonance imaging. A stereotactic biopsy of a heterogeneous lesion in the left occipital lobe was performed, which revealed demyelination along with lymphocytic infiltration, reactive astrocytosis, abundant T cells, and foamy macrophages. There was no evidence of monoclonality, rapid regression of all lesions occurred, and the patient was thus treated for tumefactive demyelination. Three months later, all of the residual lesions had enlarged and were homogeneously enhancing. An endoscopic-guided biopsy of the right periventricular lesion showed diffuse atypical lymphoid cells.

Conclusion:

The sentinel lesion of PCNSL expresses a variable histological pattern of inflammatory cells. This case demonstrates a unique and rare picture of mixed perivascular and parenchymal infiltration of inflammatory cells, highlighting the importance of repeated biopsies and/or radiological examinations to obtain an accurate diagnosis.

Inflammatory Demyelinating Lesions: True Sentinel Lesion or Immune-Mediated Response to Lymphoma?

BACKGROUND

Inflammatory demyelinating changes in the absence of malignant cells can sometimes be found on initial biopsies preceding the diagnosis of primary central nervous system lymphoma (PCNSL), resulting in the term "sentinel" lesion. Sentinel lesions have been reported sporadically in literature, resulting in many cases of misdiagnosis and delayed treatment. We aim to address the problem of misdiagnosis in PCNSL presenting as inflammatory demyelinating changes or sentinel lesions on initial biopsies, and to discuss our view of the mechanism underlying this phenomenon.

CASE DESCRIPTION

Herein we report 3 cases of PCNSL that were diagnosed via brain biopsy. We retrospectively reviewed 2 cases of initially misdiagnosed PCNSL presenting with sentinel lesions at our institution. Careful revision of preoperative magnetic resonance imaging (MRI) revealed heterogeneously enhancing tumors with strong peripheral enhancement and hypoenhancing cores. Analysis of our 2 cases revealed that initial biopsy samples in both patients were taken from the hypoenhancing regions on MRI. In the third case, we targeted the peripherally enhancing region for sampling and arrived at the proper diagnosis of PCNSL on initial biopsy.

CONCLUSIONS

Based on our cases and those reported in literature, we speculate that the inflammatory demyelinating changes observed on initial biopsies are immune-mediated responses that coexist with PCNSL in different tumor regions, and that they are the direct result of inadvertent sampling from hypoenhancing regions of the tumor, rather than sentinel lesions, as their name implies. We strongly recommend that biopsy target the most enhanced region on MRI when there is high clinical and radiologic suspicion for PCNSL.

A diagnostic challenge of primary Central nervous system lymphoma: from the eyes to the brain

Background: Being a subtype of primary central nervous system lymphoma (PCNSL), primary vitreoretinal lymphoma (PVRL) is a rare and fatal intraocular malignancy manifesting as blurred vision and floaters, and is usually combined with, or eventually progresses to, central nervous system lesions. The diagnosis of PVRL/PCNSL remains challenging because of the nonspecific clinical features and diagnostic dependency on biopsy.Case presentation: In this paper, we present the clinical, imaging, laboratory, brain biopsy, and vitreous biopsy findings of a 56-year-old immunocompetent woman who presented with blurred vision of the left eye, but which rapidly evolved into lesions of the central nervous system. The dramatic changes on brain imaging and the undiagnostic brain and vitreous biopsy results presented great challenges for the diagnosis. PCNSL was eventually presumed according to comprehensive consideration of the disease progression pattern, the characteristic neuroimaging, and molecular hints.Conclusions: PCNSL is a highly invasive tumor, and timely diagnosis is the key point in clinical practice. However, the requirement for biopsy and the existence of sentinel lesions impedes the diagnosis. Therefore, follow-up and repeated biopsy is always necessary for a definitive diagnosis. This case indicates that a complete evaluation of neuroimaging, ophthalmic testing, cytologic examination of the cerebrospinal fluid, diagnostic vitrectomy, and brain biopsy are essential for diagnosis of PCNSL. Moreover, molecular and cytokine analyses are useful adjuncts to the diagnostic cytology. Of note, the analysis of cytokine levels (IL-10/IL-6) is an important auxiliary diagnostic strategy in the diagnosis of diffuse large B-cell lymphoma.