Abstract

Primary CNS Lymphoma is rare aggressive malignancy that originates entirely in the central nervous system. It represents a diagnostic challenge to clinicians as symptoms are frequently non–specific, and overall represents 4% of intracranial neoplasms.¹ Cerebral amyloid angiopathy is characterised pathologically by deposition of amyloid in small and medium vessels arteries of the cortex and leptomeninges. It is usually restricted to the leptomeninges and grey matter and stops abruptly when a perforating vessel reaches the junction of the cortex and subcortex. This explains why the haemorrhages are almost always lobar, CAA Makes vessels fragile and more likely to rupture.²

We present a case that has not been reported in previous literature of an 82 year old man first seen in clinic with probable transient ischemic attacks secondary to a heavily calcified right ICA in October 2012. Magnetic Resonance demonstrated a sizeable area of old hemorrhage in the right frontal lobe, and he discharged with clopidogrel. However he represented In December 2012 on three occasions over the course of a week with similar symptoms of left arm weakness and facial droop. Repeat MRI illustrated no new infarcts but a further hemorrhage in the right frontal region just caudal to the previous hemorrhage which has resolved.

Further collateral revealed a 1 year history of cognitive decline and rapid deterioration in mobility since September 2012. Given the diagnostic uncertainty, an open right frontal biopsy was performed by the neurosurgeons. Histopathology demonstrated brain tissue with a focal infiltrate with large lymphoid cells with conspicuous nucleoli and a diffuse growth pattern consistent with a high grade CNS lymphoma. Immunostaining was Positive for CD20, CD79a, BCL–2, Negative for CD10, Cyclin D–1 and Tdt. Congo red staining was positive for amyloid in parenchymal vessels and Leptomeningeal vessels. Further lumbar puncture did not show any malignant cells.

Therefore in addition to the Primary Diffuse Large B–Cell Lymphoma of the central nervous system he had co–existing cerebral amyloid angiopathy. Due to his poor performance status and multiple co–morbidities after review by the oncologists he was initiated on high dose dexamthasone, and consented for Palliative whole–brain radiotherapy.

In the context of the current biopsy it was established that the two conditions have interacted because there is evidence of an old hemorrhage in addition to the deposit of the Lymphoma. Cerebral amyloid angiopathy due to beta amyloid (as in this case) can be associated with Alzheimer's disease. However cerebral amyloid angiopathy can be inherited or can also be sporadic. The load of amyloid plaques in the present biopsy was small and does not suggest co–existing Alzheimer's disease.³