Non-Hodgkin Lymphoma Mimicking Chronic Subdural Hematoma: Case Report

67-year-old white female patient with a history of behavioral change and chronic headache. Magnetic resonance imaging showed hypointense concave-convex subdural collection. In the intraoperative period, a mass was evidenced and biopsy material was collected. The histo-pathology result revealed a non-Hodgkin’s B-cell lymphoma. This case highlight the importance of performing biopsy when intraoperative is identified noncombatant lesion with the diagnostic hypothesis raised based on findings of radiology and to realize the fact that MRI may not safely differentiate between chronic subdural hematoma and other subdural lesions.

Primary lymphomas of the central nervous system correspond to 0.85% to 2.0% of tumors of the central nervous system. They may present as subdural collections in up to 15% of cases and, in the first analysis, be confused with chronic subdural hematoma. This is a report of a patient with a radiological image suggestive of chronic subdural hematoma (CSH), but the final diagnosis was a B-cell non-Hodgkin's lymphoma in the central nervous system.  Chronic subdural hematomas (CSH) occur more frequently in elderly patients and the signs and symptoms expressed are nonspecific.
Any mass lesion occupying the subdural space may theoretically reproduce a chronic subdural hematoma in an initial evaluation [1].
There was no report of fever, weight loss or seizures. There was no evidence of infection; CSF examination was normal. Test for HIV and Epstein-Barr Virus were negative. She underwent trephination surgery, with two holes to the right. In the intraoperative period, a mass was evidenced and biopsy material was collected ( Figure 3). A small craniotomy was performed to amplify the surgical field. During hospitalization, the patient developed generalized tonic-clonic seizures well controlled with antiepileptic drugs. There was no deterioration of the neurological status.
The patient was referred to follow-up with oncology team but unfortunately died without quimo-heraphy and radio-therapy treatment being completed.
A literature review of the articles related to the case was carried out and the patient's medical history was collected in the medical record.
Primary lymphomas of the central nervous system (LNPS) present as extra-axial collections with radiological characteristics similar to chronic subdural hematoma [2]. On magnetic resonance imaging, T1-weighted images reveal isointense or hypointense lesions. In T2-weighted images may appear hyper-intense. Catana., et al. demonstrated the CSH is hypointense at T1-weighted in 41% of cases and hyperintense at T2-wieghted in 72% [3]. In our case, the T1-weighted image appeared hypo-intense, although on T2-weighted the subdural mass was hypo-intense.

Conclusion
There was no conflict of interest.

Bibliography
Another diagnosis mimicking a subdural hematoma is present in other cases described in the literature. Reys and coworkers presented a case of a patient diagnosed with a chronic encapsulated subdural hematoma which, in fact, was dural lymphoma [4]. Souza Filho., et al. reported a case of Burkit's lymphoma presenting with characteristics of chronic subdural hematoma [5]. In addition, if the patient presented a history of traumatic brain injury (TBI), it is possible to confuse the diagnosis. For example, Ramnarayan., et al. reported a case of a patient with a previous history of TBI with extra-axial collection on initial imaging examination suggestive of chronic subdural hematoma that was, in fact, a lymphoma [6].
LPSNCs present perivascular infiltrate, which spreads by centrifugation, and may invade the cerebral parenchyma [7]. The brain lesions may be multiple and involve deep structures of the gray matter, as well as of the white matter, often presenting areas of necrosis.
However, they may occur exclusively in leptomeninges [8,9], as seen in our case. In a systematic review, Catana., et al. identified 29% of cases of lymphoma in a patient with subdural collection on imaging examination [3].
We report the case to highlight the importance of performing biopsy when the something unusual is identified during surgery, mostly when the lesion can lead to a disease with other treatment than surgery alone. It's important to the surgical team that the MRI may not safely differentiate between chronic subdural hematoma and other subdural lesions, so we must have as differential diagnosis of subdural lesions also lymphomas.
It is important to make an adequate evaluation in cases of subdural mass and include in the differential diagnosis the possibility of a lymphoma.