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CASE REPORT
Year : 2022 | Volume
: 8
| Issue : 4 | Page : 219-221
Diffuse large B-cell lymphoma: An uncommon diagnosis at the cerebellopontine angle - A case report
Punit Kumar1, Amit Kumar Ghosh1, Soutrik Das2
1 Department of Neurosurgery, Institute of Neurosciences, Kolkata, West Bengal, India
2 Department of Neuropathology, Institute of Neurosciences, Kolkata, West Bengal, India
Correspondence Address:
Punit Kumar
Department of Neurosurgery, Institute of Neurosciences, AJC Bose Road, Kolkata - 700 017, West Bengal
India
Source of Support: None, Conflict of Interest: None
CheckDOI: 10.4103/bc.bc_46_22
Primary central nervous system lymphoma (PCNSL), a rare variant of extranodal non-Hodgkin's lymphoma, has shown an increased incidence over the last 3–4 decades in both immunocompromised and immunocompetent individuals. Only <20 cases of cerebellopontine (CP) angle lymphoma have been reported so far in the literature. Hereby, we report a case of primary lymphoma of the CP angle mimicking vestibular schwannoma and other common pathologies at the CP angle. Hence, while evaluating a lesion at CP angle, PCNSL should always be considered in the differential diagnosis.
Keywords: Cerebellopontine angle, non-Hodgkin B-cell lymphoma, primary central nervous system lymphoma, vestibular schwannoma
Highlights
Primary central nervous system lymphoma should always be considered in the differential diagnosis of CP angle lesionSurgical intervention is limited to establishing tissue diagnosis only. Introduction
Primary central nervous system lymphoma (PCNSL) is a rare entity, generally involving the brain more commonly than the spinal cord.[1] It is predominantly non-Hodgkin's lymphoma type, and diffuse large B-cell lymphoma is the most common form of central nervous system lymphoma. Although PCNSL is mostly thought to be associated with congenital, iatrogenic, or acquired immunosuppression, it is now increasingly recognized in immunocompetent individuals also.[2] Extra-axial PCNSL mainly arises in the white matter of the brain.[3] Despite showing good response to radiotherapy and chemotherapy, a mean survival duration of only 15–45 months and 3–6 months has been reported with and without treatment, respectively.[4] Surgical intervention is limited to establishing tissue diagnosis, as PCNSL is often multifocal with a tendency to involve the subarachnoid space. Only <20 cases of CP angle lymphoma have been reported so far in the literature. Hereby, we report a case of primary B-cell lymphoma at the cerebellopontine (CP) angle. The rarity of this disease location prompted us to report this case.
Case ReportA 36–year-old Asian female presented with a 3-month history of progressive right hemicranial pain involving the right half of her face and imbalance while walking. A thorough clinical examination revealed the involvement of all three branches of the right trigeminal nerve with mild right cerebellum hemispheric involvement.
Magnetic resonance imaging (MRI) revealed a well-defined lesion of approximately 4 cm × 3 cm, in the right cerebellopontine angle. The lesion appeared isointense on T1- and T2-weighted MR images, with significant edema involving the cerebellum and brainstem. It was homogeneously enhanced with gadolinium along with periventricular enhancement, [Figure 1]. Computed tomography (CT) scan brain revealed no erosive changes of the bone. To confirm the diagnosis, surgery was performed. A lateral suboccipital approach was used to obtain a biopsy from the lesion located at the CP angle. An ill-defined lesion was noted in the CP angle, posterior to the 7th and 8th nerve complex, and infiltrating into the cerebellum. Upper and lower neurovascular complexes were not involved by the lesion, [Figure 2]. Hematoxylin- and eosin-stained tissue showed neoplastic lymphocytic invasion and these cells cross-reacted with CD20 antibody suggesting that the lesion was a large B-cell lymphoma [Figure 2]. The patient was sent to the oncology center for further staging and management.
Figure 1: T1, T2, and contrast MRI brain showing enhancing lesion with periventricular enhancement
Figure 2: Intraoperative view of lesion with lymphocytic invasion and CD-20 positivity on immunohistopathology Discussion The abovementioned case describes the occurrence of large B-cell lymphoma at the CP angle. Although metastatic lymphoma at the skull base is previously reported in some cases, primary lymphoma at the CP angle location is very rare, with <20 cases reported in the literature.[5] Genetic analysis has recently identified the role of the JAK-STAT pathway. Other important pathways identified and actively being investigated include NFkB DNA modification, CDKN2A deletions, B-cell receptor signaling, and mutations in MYD88, L265P, and CD79B.[6]
The main differences between lymphoma and other mass lesions at the CP angle are illustrated in [Table 1]. Other MRI sequences, such as dynamic contrast-enhanced MRI and dynamic susceptibility contrast MRI, help differentiating from other pathologies.[7] Systemic spread is assessed by positron emission tomography-CT whole body. The role of surgery in such cases is limited to biopsy of the lesion for tissue diagnosis. Histopathologic examination reveals perivascular cuffing of malignant cells with an almost constant expression of pan-B-cell markers (CD19, CD20, CD22, and CD79a) on IHC.[8] In our case, CD20 positivity was reported on immunohistochemistry.
Table 1: Radiological characteristics of common cerebellopontine angle massesThese tumors are highly sensitive to chemotherapy and radiotherapy. Currently, the first-line treatment standard is HD-MTX (high-dose methotrexate) based induction chemotherapy.[9] Salvage chemotherapy is used in refractory cases or in cases with partial response. Autologous stem-cell transplantation and whole-brain radiotherapy are used for consolidation treatment.
ConclusionThis case report describes a large B-cell lymphoma at a rare location (CP angle). It further emphasizes the importance of clinicoradiological correlation. These rare pathologies should always be kept in mind in the differential diagnosis of CP angle masses.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
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Conflicts of interest
There are no conflicts of interest.
References
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