A Unique Case of Intraparenchymal Chemotherapy due to Ventricular Access Device Misuse: A Cautionary Tale

Background: Ommaya reservoirs are ventricular access devices used for chemotherapeutic treatment of hematological malignancies with CNS involvement. We report a case describing inadvertent intra-parenchymal spread of chemotherapy resulting from unrecognized failed access of the device. Presentation: A 56 year old male had an Ommaya reservoir placed for relapsed monoclonal acute myeloid leukemia with CNS involvement. Routine post-operative CT was unremarkable and demonstrated satisfactory device placement. After the device was accessed and utilized, subsequent CT disclosed new moderate sized intra-parenchymal hemorrhage centered on the Ommaya catheter with significant scalp hematoma. Fluoroscopic ventriculogram demonstrated faulty access with contrast filling around the reservoir and tracking through the burr holes into brain parenchyma. Reaccessing the device correctly showed a patent system without extravasations and normal drainage into ventricular CSF pathways. Conclusions: Adequate training and supervision is necessary for accessing ventricular reservoirs to prevent local extravasation. This case illustrates that extravasation may extend through the burr hole to affect adjacent brain parenchyma, falsely simulating a detached catheter. Fluoroscopic ventriculograms are useful in diagnosing problems with intraventricular catheters and in this case the patency of the Ommaya reservoir system was demonstrated, allowing its ongoing use after correct cannulation.