Primary dural lymphoma: Case report

Primary Dural lymphoma (PDL) is a rare pathology that occurs in immunocompetent patients. In such cases, these lesions may mimic more common intracranial tumors. We present the case of a patient who presented an intra cranial hypertension syndrome; the brain MRI showed a tissular mass that we took for a meningioma; upon surgical intervention, an occult mass was discovered. Major excision and immunohistochemistry demonstrated PDL. Our case report highlights the rarity of these pathology and the importance of combined surgery and medical treatment, as the latter can be treated with chemoradiation with good clinical outcomes.


Introduction
Primary central nervous system lymphoma (PCNSL) is a rare variant of non-Hodgkin's lymphoma (NHL), which is restricted to the brain, leptomeninges, cranial nerves, spinal cord, or intraocular compartment without involvement of other organ systems [3]. Primary dural lymphoma (PDL) is a subtype arising from this larger group. This pathology is accounted for less than 1% of all central nervous system (CNS) lymphomas and <0.1% of all non-Hodgkin's lymphomas generally [1,6]. Based on the site of arising the lymphomas can be divided nodal or extra nodal. In this observation we report a case of primary dural lymphoma in immune competent patient revealed by a intra cranial hypertension (see Figs. 1-5).

Case report
Our patient is 61 years old with no pathological history. Her symptoms began with an inaugural seizures 2 months before her admission associated to headaches, without any other symptoms.
The clinical examination did not find anything in particular, in particular no sensory-motor deficit or damage to the cranial nerves. Optical examination was also normal.
The surgical intervention was programmed, and a subtotal excision was realized with our professor. The tumor attachment was on falx, and it was fibrous non-vacuumable.
The post operative follow-up simple without hemorrhagic complications and without the occurrence of a deficit. The patient was transferred to hematology department. This case has been reported in line with the 2020 SCARE guidelines [7].

Discussion
Primary dural lymphoma (PDL) is a subtype arising from a larger group called primary central nervous system lymphomas (PCNSL). PCNSL are extra nodal non-Hodgkin lymphomas originating from the brain, meninges or spinal cord [1]. PDL are defined as an extra nodal lymphoma in the absence of systemic disease. Primary dural lymphomas (PDL) are very rare and are in general low-grade B cell lymphomas in anatomopathological examination [2]. The incidence of PCNSL is higher in immunocompromised patients, whereas PDL is seen in immune competent patients. PDL is rare and very few cases are reported in the literature that doesn't exceed the fifteen cases [1].
Our case exposes a PDL in a immune competent patient with small cell B lymphoma objectified in immunohistochemical examination.
PDL arises from the dura mater and belongs to the low-grade B-cell marginal zone group of tumors which is non-specific for CNS pathologies which are mostly high-grade diffuse large B-cell lymphomas [1].
PCNSL is a chemo sensitive and radiosensitive tumors. PDL has a better prognosis than PCNSL. Chemotherapy is used as a first-line treatment in dural lymphomas 7,8: chemotherapy drugs reach the dural tumor without passing the blood-brain barrier [2].
PDL tends to respond positively to surgery and radiotherapy. They are preferable choices due to its indolent character and high radio sensitivity but requires relatively low doses of radiotherapy [4,5]. Although there are limited reports and PDL is quite rare [1].
PDL has a better prognosis than other PCNSLs [2]. Without treatment, the prognosis for PCNSL is dismal (median survival of 1.5 months after diagnosis). Standard of care therapy with high dose methotrexate (MTX) in combination with other chemotherapy agents (rituximab, cytarabine) followed by whole brain radiation greatly improves overall survival up to a median of three years [3].

Conclusion
Primary dural lymphoma are a very rare type of central nervous tumor. Its radiologic aspect can lead to misdiagnosis in the radiological examination. Anatomopathological examination is the key to the diagnosis. Surgery associated with chemo and radiotherapy can improve the prognosis, which remains poor.   2. A brain MRI showed the same image with dural attachment on the right frontal lobe.

Financial disclosure
The authors declared that this study has received no financial support.

Ethical approval
Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.

Provenance and peer review
Not commissioned, externally peer-reviewed.

Sources of funding
None.

Consent
Written informed consent for publication of their clinical details and/or clinical images was obtained from the patient.

Ethical approval
Ethical approval has been exempted by our institution.

Research Registration Unique Identifying Number (UIN)
None.

The trial registry number -ISRCTN
None.

Author contributions
Jihane Saidy: writing the paper. Abderrazzak Bertal: writing the paper. Saad Hmada: writing the paper. Nidal Aamara: writing the paper. Yassine Tahrir: writing the paper and Corresponding author. Sarah Moukhlis: writing the paper. Mohamed Karkouri: Correcting the paper. Abdessamad Naja: Correcting the paper. Abdelhakim Lakhdar: Correcting the paper.

Declaration of competing interest
The authors declare having no conflicts of interest for this article.