Accepted Manuscript Muslin granuloma mimicking parenchymal hematoma in a patient with seizures 30 years after aneurysm wrapping Mougnyan Cox, MD, Neda I. Sedora-Roman, MD, Omar Choudhri, MD PII: S1878-8750(18)31973-9 DOI: 10.1016/j.wneu.2018.08.190 Reference: WNEU 9048 To appear in: World Neurosurgery Received Date: 1 July 2018 Revised Date: 22 August 2018 Accepted Date: 23 August 2018 Please cite this article as: Cox M, Sedora-Roman NI, Choudhri O, Muslin granuloma mimicking parenchymal hematoma in a patient with seizures 30 years after aneurysm wrapping, World Neurosurgery (2018), doi: 10.1016/j.wneu.2018.08.190. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. ACCEPTED MANUSCRIPT Title: Muslin granuloma mimicking parenchymal hematoma in a patient with seizures 30 years after aneurysm wrapping Authors: 1: Mougnyan Cox MD (Corresponding Author) RI PT Fellow, Division of Neuroradiology Hospital of the University of Pennsylvania 3400 Spruce Street, Philadelphia, PA, USA 2: Neda I. Sedora-Roman MD Hospital of the University of Pennsylvania 3400 Spruce Street, Philadelphia, PA, USA 3: Omar Choudhri MD M AN U Fellow, Section of Interventional Neuroradiology, SC Email: mougnyan.cox@uphs.upenn.edu Attending Physician, Division of Neurosurgery TE D Hospital of the University of Pennsylvania 3400 Spruce Street, Philadelphia, PA, USA EP Keywords: Muslinoma; muslin granuloma; mimicking; hematoma AC C Abbreviations: CT= Computed Tomography, MRI = Magnetic Resonance Imaging ACCEPTED MANUSCRIPT Title: Muslin granuloma mimicking parenchymal hematoma in a patient with seizures 30 years after aneurysm wrapping Keywords: Muslinoma; muslin granuloma; mimicking; hematoma RI PT Abbreviations: CT= Computed Tomography, MRI = Magnetic Resonance Imaging Case: M AN U SC An 82-year-old woman was emergently transported to the Emergency Department (ED) of a tertiary-care institution for a witnessed convulsive seizure and fall. No prior imaging or history was available at the time of initial evaluation. Upon evaluation in the ED, she was confused and somnolent, but arousable. She had no focal neurologic deficits. Her vital signs were only notable for mild tachycardia. While undergoing evaluation in the ED, she had another witnessed convulsive seizure which was terminated after the intravenous administration of 5mg lorazepam. Postictally, she had a left facial droop and mild left pronator drift, raising concern for an acute stroke. An acute stroke alert was initiated, and she was transported to the ED CT scanner for a CT angiogram of the head and neck to rule out an intracranial large vessel occlusion. Immediately after the CT scan, she had another convulsive seizure without a return to her mental baseline. She was intubated for airway protection and started on antiseizure medications. AC C Discussion: EP TE D On the CT, there was a 13mm hyperdense intraparenchymal mass with mild surrounding vasogenic edema within the right anterobasal frontal lobe (see Figure 1), immediately adjacent to a broad-based 4mm anterior communicating artery aneurysm (AComm). The constellation of findings was concerning for early rupture of an AComm aneurysm, with a small acute intraparenchymal hematoma. She was taken emergently to the hybrid angiography suite-operating room, where the aneurysm was coiled successfully. Later during the hospital stay, her family brought in hospital records and images showing that she had muslin wrapping of her AComm aneurysm 30 years ago, with stable size and configuration of the right inferior frontal intraparenchymal mass for several years. Imaging findings on CT and MRI combined with the stability of the lesion over several years was consistent with the diagnosis of a muslin granuloma. Muslin foreign body granulomas are a known complication of muslin aneurysm wrapping, and have been associated with vision loss from optochiasmatic arachnoiditis [1,2]. In some instances, the inflammatory reaction surrounding the granuloma may be confused for an abscess as a result of ring-enhancement and/or edema [3,4]. Our case is unique and unusual because the imaging appearance of a hyperdense mass adjacent to an AComm aneurysm were highly suggestive of a ruptured aneurysm with an intraparenchymal hematoma, triggering the ruptured aneurysm pathway. In the absence of prior imaging, muslin granulomas can occasionally be mistaken for intraparenchymal hemorrhage. Careful comparison with prior imaging and knowledge of prior history of aneurysm wrapping can help distinguish a new hematoma from a foreign body granuloma. ACCEPTED MANUSCRIPT Figures: M AN U SC RI PT Figure 1: AC C EP Figure 2: TE D The first image in figure 1 is a noncontrast CT showing a 13mm hyperdense intraparenchymal mass in the right anterobasal frontal lobe (blue arrow), with minimal surrounding low signal. The second image is a concurrently performed CT angiogram of the head, showing a 4mm anterior communicating artery aneurysm (blue arrow) adjacent to the hyperdense mass. These constellation of findings were interpreted by the neuroradiologist as concerning for early rupture of an AComm aneurysm, with a small adjacent intraparenchymal hematoma. M AN U SC RI PT ACCEPTED MANUSCRIPT References: TE D The first image in Figure 2 is a shaded 3D surface display reconstructed from the intraoperative conventional angiogram showing the 4mm AComm aneurysm (arrow). The second image is an intraoperative control angiogram showing interval coil embolization the AComm aneurysm (arrow), with no significant residual filling. 1: McFadzean RM, Hadley DM, McIlwaine GG. Optochiasmal arachnoiditis following muslin wrapping of ruptured anterior communicating artery aneurysms. Journal of Neurosurgery. 1991 Sep;75(3):393-6. EP 2: Haisa T, Matsumiya K, Yoshimasu N, Kuribayashi N. Foreign-body granuloma as a complication of wrapping and coating an intracranial aneurysm: Case report. Journal of Neurosurgery. 1990 Feb;72(2):292-4. AC C 3: Brochert A, Reynolds T, Baker R. MRI in a case of muslin-induced granuloma. Neuroradiology. 2003 Feb 1;45(2):82-4. 4: Kumar R, Jeyaseelan Nadarajah AK, Gamanagatti S. Misery of neurosurgeon: gauzoma causing foreign body granuloma-role of radiologist. Asian Journal of Neurosurgery. 2016 Jan;11(1):74. ACCEPTED MANUSCRIPT Highlights: RI PT SC M AN U TE D EP • Muslin wrapped aneurysms can convincingly mimic parenchymal hematomas on rare occasions Careful comparison with prior imaging and knowledge of aneurysm wrapping can suggest this diagnosis In the absence of prior imaging/history, a patient with acute neurologic symptoms and a hyperdense mass adjacent to an aneurysm should be presumed to have a ruptured aneurysm until proven otherwise AC C • •