Intraparenchymal low-grade B-cell lymphomas of the central nervous system: Clinicopathologic and molecular analysis of three cases and a review of the literature

Primary central nervous system (CNS) lymphomas represent 1 % of all non-Hodgkin lymphomas, with diffuse large B-cell lymphomas as the prevailing subtype. Low-grade B-cell lymphomas are exceptional with only 24 marginal zone B-cell lymphomas (EMZL) and 1 follicular lymphoma (FL) previously reported so far. While their molecular profiles are studied elsewhere, data on primary intraparenchymal CNS cases remain limited. The objective of the present study is to contribute new cases of primary intraprenchymal low-grade B-cell lymphomas in the CNS and characterize their mutational profile. We conducted a comprehensive review of cases and a literature review to identify similar instances. Clinical, imaging, histological, immunohistochemical, and molecular characteristics were analyzed. Diagnoses were established according to established criteria. We present three novel cases of intraparenchymal CNS low-grade B-cell lymphomas. One case of intraparenchymal EMZL exhibited plasmacytic differentiation, while another lacked a plasma cell component. The third case was diagnosed as FL. The L265P mutation of MYD88 was absent in all cases. Next generation sequencing revealed pathogenic mutations in SPEN (Glu1970ValfsTer64) and ARID1A (Pro1355LeufsTer118) genes in one EMZL case. In conclusion, intraparenchymal CNS low-grade B-cell lymphomas are rare, with few reported cases. Our findings expand knowledge on their clinical and molecular features. We present the first molecular profile of primary CNS intraparenchymal EMZL, underscoring the need for further research to understand their biology and optimize treatment strategies.

Unusual localization and clinical presentation of primary central nervous system extranodal marginal zone B‑cell lymphoma: A case report

Primary central nervous system (CNS) extranodal marginal zone B-cell lymphoma (MZBL) is a rare low-grade non-Hodgkin lymphoma, characterised predominantly by small B cells, plasma cells, monocytoid cells and scattered large immunoblasts. Primary CNS MZBL is a slow-growing tumour that remains localised and is characterised by an excellent clinical prognosis. The present study describes the case of a 48-year-old HIV-negative female patient with a history of head trauma 1 year prior, who presented with worsening neurological symptoms and a magnetic resonance imaging finding of a ~3-cm extra-axial mass within the left lateral ventricle. From histopathology and immunohistochemistry, the lesion was diagnosed as a CNS MZBL; as no other primary lesions were found, the base of the choroid plexuses of the left lateral ventricle was considered the primary site. To the best of our knowledge, the current case is the first study to report on primary CNS MZBL arising in this anatomical site and paves the way for further studies on the role of chronic inflammation (in the present case resulting from trauma) in the pathogenesis not only of primary CNS MZBL but also of lymphoma in general. Additionally, this report could serve as a starting point for studies analysing the role of meningothelial cells in the pathogenesis of primary CNS MZBL.

Intraparenchymal Mucosa-Associated Lymphoid Tissue Lymphoma: A Case Report

Marginal zone B-cell lymphoma (MZBCL) of mucosa-associated lymphoid tissue (MALT) type, which is primary to the central nervous system (CNS), is a rare lesion, with those originating within the parenchyma even more so. We present the case of a 64-year-old male with weakness in the left hand and focal motor seizures of his arm, who was found to have a right frontal intraparenchymal lesion. Following resection, histopathological and immunohistochemical evaluations were completed, leading to a diagnosis of a primary CNS MZBCL of MALT type in the context of a negative workup of systemic disease. Neuroimaging, histopathological, and immunohistochemical findings, as well as a comprehensive literature review of similar cases, are discussed.

Primary mucosa-associated lymphoid tissue lymphoma in the midbrain: A case report

BACKGROUND

Primary non-dural central nervous system mucosa-associated lymphoid tissue (MALT) lymphoma is a rare indolent B-cell lymphoma, with only a few reported cases worldwide.

CASE SUMMARY

A 33-year-old man presented with a 5-mo history of left blepharoptosis and a 4-mo history of right limb numbness and weakness. Magnetic resonance imaging showed a significantly enhanced mass in the left midbrain. Subsequent positron emission tomography revealed that the lesion had increased glucose uptake. A stereotactic robotic biopsy supported a diagnosis of MALT lymphoma. Then he was treated with radiation therapy (30Gy/15F), which resulted in complete remission. We also review the literature on brain parenchymal-based MALT lymphoma, including the clinical presentation, treatment options, and outcomes.

CONCLUSION

Although there is no consensus on the optimal treatment for this rare disease, patients can respond well when treated with radiotherapy alone.

Extranodal Marginal Zone Lymphoma of the Central Nervous System Includes Parenchymal-Based Cases With Characteristic Features

OBJECTIVES

To define the clinicopathologic features of extranodal marginal zone lymphoma (EMZL) of the central nervous system (CNS), including cases arising in CNS parenchyma, which have been reported only rarely.

METHODS

Twelve cases of CNS EMZL were identified, including 5 based in CNS parenchyma and 7 nonparenchymal cases arising in dura or choroid plexus.

RESULTS

Histologically, parenchymal cases were perivascular infiltrates without a dominant lymphoid mass, whereas nonparenchymal cases were masses of small lymphocytes. Plasma cells were a larger component of the infiltrate in parenchymal cases (median, 30%; range, 20%-50%) than nonparenchymal cases (median, 0%; range, 0%-5%; P < .001), and plasma cells were clonal by immunohistochemistry in 4 of 5 parenchymal vs 1 of 7 nonparenchymal cases (P = .07). Fluorescence in situ hybridization for MALT1 rearrangement was positive in 1 of 3 parenchymal and none of 3 nonparenchymal cases. Chromosomal microarray was abnormal in 5 of 7 cases (71%), with chromosome 6/6q alterations identified in 3 cases. No patients with parenchymal disease but all 6 (100%) with nonparenchymal disease achieved complete remission.

CONCLUSIONS

This case series, the first to include multiple parenchymal cases, clarifies the spectrum of clinical, pathologic, and genetic findings in CNS EMZL and suggests that parenchymal-based lesions may show less favorable prognosis than dural-based disease.

Extranodal Marginal Zone Lymphoma of the Central Nervous System

Extranodal marginal zone lymphoma of the central nervous system (CNS EMZBL) is a rare disease. We present a review of the literature and describe its presentation, differential diagnosis, treatment options, and outcomes. Systematic search of PubMed, Medline, and Embase databases via the Ovid engine for primary articles and case reports yielded 37 unduplicated peer-reviewed articles of CNS EMZBL. We identified 69 cases in these articles and 1 unreported case at our institution, which were included for this review's analysis. Median age at diagnosis was 55 years (range, 18-78 years), with a female preponderance of 77% (n = 54). Most common presenting symptoms were headache in 43% (n = 30), seizures in 31% (n = 22), and visual defects in 27% (n = 19). The most common treatment modalities were localized therapies, which were provided to 67% (n = 47) of cases. These included radiotherapy in 27% (n = 19), radiotherapy with surgery in 24% (n = 17), and surgery alone in 16% (n = 11). Ninety percent (n = 63) of patients had a median follow-up of 23 months. Complete remission was experienced by 77% (n = 49) patients, and 22% (n = 14) were alive with disease. Three patients had evidence of relapse, and one patient died. CNS EMZBL is an indolent, low-grade, radiosensitive lymphoma with good treatment outcomes and prognosis. It is an important differential to consider in extra-axial dural-based masses. Individualized management plans, with preference given to localized treatment options, should be considered after factoring in the site and extent of disease, its resectability, and the expected adverse effects of systemic therapy.

Masses in the membranes

A 24-year-old woman with systemic lupus erythematosus presented with a 1-year history of painless vision loss in the right eye. Examination was notable for a bitemporal hemianopia. Brain imaging revealed multiple contrast enhancing dural masses, including one along the planum sphenoidale. She underwent excisional biopsy for a presumed diagnosis of multiple meningiomas. Five years later, she developed worsening vision in the left eye, hypesthesia in the V1 distribution, and oculomotor nerve palsy. Repeat imaging showed an enhancing mass in the cavernous sinus and orbital apex. Biopsy demonstrated a lymphoplasmacyte rich infiltrate in dense extracellular material. She was diagnosed with lupus-induced hypertrophic pachymeningitis and started on immunosuppressive therapy. On further worsening of symptoms, her initial biopsy was reexamined and revealed a kappa light chain restricted B-cell and plasmacyte population. This led to the final diagnosis of central nervous system extranodal marginal zone lymphoma.