Case Report: Primary dural based diffuse large B-Cell lymphoma in a 14 year-old boy

Primary dural lymphoma is a subentity of primary leptomeningeal lymphoma which represents 0.1% of all non-Hodgkin’s lymphomas. Only five cases have been reported so far. We report a very rare case of primary dural-based lymphoma in a 14 year-old boy presenting with mass effect. The patient was managed with excision of the lesion and removal of the involved bone. Post-operatively, the patient showed good recovery. He was then referred to the oncology unit for further chemo- and radiation therapy. A high index of suspicion should therefore be kept in order to diagnose the condition in a timely fashion and then plan for appropriate management since diffuse large cell lymphoma has a relatively benign clinical prognosis.


Introduction
Primary dural diffuse large B-cell lymphoma (DLBCL) is an extremely rare entity with only five cases reported so far 1 . The symptoms are nonspecific. The main differential diagnosis of the condition remains meningioma 2 . Currently there is no standard treatment due to a paucity of cases 3 . A high index of suspicion should be kept in order to diagnose the condition in a timely fashion and then plan for appropriate management since diffuse large cell lymphoma has a relatively benign clinical prognosis 4 . Here we report a case of a primary dural based DLBCL in a 14 year-old boy presenting with herniation syndrome, who improved after surgical excision and is currently on chemotherapy.

Case report
A 14 year-old Tharu boy, from Siraha (a remote village in Nepal) presented to our emergency department with a sudden onset altered sensorium which lasted for 1 day. The patient had a history of intermittent headaches and vomiting over the last 3 months. The patient's parents also noticed significant weight loss and the presence of scalp swelling for the last 2 months. There was no remarkable family history. Previous treatment history revealed that the patient had been taken to India 1 month back, where fine needle aspiration cytology (FNAC) of the scalp lesion in the parietal region had revealed Non-Hodgkin's lymphoma. The patient party was told the prognosis and advised for chemo-and radiation therapy but this was refused because of their poor financial status and so the family returned back to Nepal.
On initial examination at our ER room, the patient attained a Glasgow Coma Scale (GCS) of E2M4V2 with anisocoria on the left side. There were two scalp swellings on the left parietal and the frontal regions ( Figure 1) which were soft and fluctuant. Serology performed was negative for human immuno-deficiency virus (HIV) and hepatitis B and C. Computed tomography (CT) scan of the head was performed, revealing a dural-based hyperintense lesion on the frontal and parietal region with subfalcine herniation (Figure 2 and Figure 3) and honeycomb appearance of the involved bone ( Figure 4). Ultrasonography of the abdomen revealed no significant lymph nodes.   Because the child was already herniating, he was started on intravenous dexamethasone (4mg over 8 hours) and a single 100ml dose of 25% mannitol was given. Parents were counseled and written consent was taken for operative management. Surgery revealed a duralbased lesion ( Figure 5) that was moderately vascular, soft and friable in consistency with involved bone showing a moth-eaten appearance ( Figure 6). Both extra-and intra-dural extension ( Postoperatively, the patient improved to GCS 15. The steroids were slowly tapered off as the mass effect and edema were absent on repeat CT image and also prolonged usage would hamper healing of scalp surgical wound. The patient was thoroughly counseled and then referred for free chemo-and radiation therapy in a government oncology hospital.

Follow-up and outcomes
The patient's GCS at 2 weeks follow-up was 4. Patient has been started on chemotherapy and is also advised for regular follow-ups.

Discussion
Primary dural lymphoma, first described by Oberling 5 , is an exceedingly rare disease entity. Only five cases of primary dural diffuse large B-cell lymphoma have been described so far with a      lesions such as meningiomas and hemangiopericytomas 2 . Since the prognosis of intracranial DLBCL is favourable 4 , it is important to make a correct and timely diagnosis. Rapid progression of the symptoms, lytic lesions on the bone and restricted diffusion in magnetic resonance imaging (MRI) may provide additional clues to the diagnosis. In cases where there are no obvious neurological symptoms, it may be advisable to take a needle biopsy of the scalp tumor as described by Ochiai et al. 7 . There has been no consensus on the correct treatment protocol in the management of dural large-cell lymphoma due to a paucity of cases 3 . Previous cases have been treated with tumor resection followed by cyclophosphamide, hydroxy-doxorubicin, oncovin (vincristine) and prednisone (CHOP) with or without rituximab-or methotrexate-based chemo regimes. Additional radiation was also tried in some cases 1 . This case is the youngest age where the entity has been observed and showed good recovery despite initial presentation with herniation syndrome. Therefore, we suggest that maintaining a high index of suspicion and timely intervention is the key to better outcome in the patients.

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

Author contributions
Dr. Sunil prepared and formatted the paper, Dr. Binod and Dr. Balaji revised the paper and Dr. Cherian approved the final draft. All authors agreed to the final content of the manuscript.

Competing interests
No competing interests were disclosed.

Grant information
The author(s) declared that no grants were involved in supporting this work. Tumor immunophenotyping using flow cytometric analysis (CD5, CD10, CD19, and CD20) and by histochemical evaluation of the lymphoid cells is mandatory. These exhibit strong immunoreactivity both to leukocyte common antigen and to B-cell marker (L26). No staining should be noted for chromogranin, synaptophysin, or the epithelial markers AE1 and AE3 .
Even though financial restriction is of concern in our country, contrast enhanced CT chest and abdomen should be the protocol to see for lymph node involvement rather than insensitive USG study.
This may be a typo error, however to correct the same: Mannitol comes in 20% and not in 25% in Nepal.
Image ( figure 9) show a limited craniotomy causing brain herniation from the site of craniectomy and has been taken at a level lower than lesion previously shown in Figure 2. To allow comparison, it is suggested to provide CT images of same level or plane.
Differential diagnosis should include meningiomas, metastases,extradural abscesses with osteomyelitis or extradural hematomas. Clues for diagnosis include a rapid progression of symptoms with permeative growth pattern with large soft tissue component in galeal and extradural compartment, restricted diffusion on MRI, and the presence of bone lytic lesions on CT, limited periosteal reaction and an angiographically avascular lesion except for blush or vascular encasement .