MAGNETIC RESONANCE IMAGING FEATURES AND OUTCOME FOR SOLITARY CENTRAL NERVOUS SYSTEMCOCCIDIOIDESGRANULOMAS IN 11 DOGS AND CATS

Abstract

Little published information is available to guide therapy for canine and feline patients with Coccidioides infections involving the central nervous system (CNS). The purpose of this cross-sectional retrospective study was to describe magnetic resonance imaging (MRI) features and outcome for a group of dogs and cats with solitary CNS Coccidiodes granulomas. Nine canine and two feline cases met inclusion criteria; four diagnosed and treated with surgery and fluconazole and seven diagnosed by serology or cytology and treated medically. Three cases had left Coccidioides endemic areas long before developing neurological disease. The MRI lesions shared many features with neoplastic masses. The extra-axial granulomas often had a lack of a distinct border between the mass and neural parenchyma. Four cases were extra-axial and seven were intra-axial, but distinguishing between extra-axial and intra-axial locations was sometimes challenging. The surgical cases had good outcomes and histology allowed definitive diagnosis. Medically managed patients also had generally good outcomes, with resolution of clinical signs in most cases. Findings indicated that distinction between neoplasia and focal Coccidioides granulomas based on MRI features is likely to be imprecise. Demonstration of the organism by cytology or histology is required for definitive diagnosis. The role of surgery for improving the outcome of brain or spinal coccidioidomycosis granulomas warrants further study.

A novel form of intracranial coccidioidomycosis is present in dogs and exhibits characteristic clinical and magnetic resonance imaging findings

“…We were unable to find a previous report of this variant in the veterinary literature at the time of this study. Intracranial coccidioidomycosis is comparatively rare, only occurring in specific regions of the world, and has only recently been more thoroughly described in the veterinary literature . The cases described in our study had characteristics that were inconsistent with the more typically described presentation of focal granulomatous lesions in the central nervous system.…”

“…Coccidioidomycosis is a fungal infection caused by the soil fungus, Coccidioides immitis and C. posadasii , common in the southwestern United States, Mexico, and parts of Central and South America . Magnetic resonance imaging (MRI) features of solitary central nervous system granulomas caused by Coccidoides infection in dogs have only recently been thoroughly described in the veterinary literature . Coccidioides is a dimorphic fungus that changes from a mycelial saprophytic form to an endospore form inside an infected animal .…”

“…Focal granulomatous meningitis has been described as well . On MRI, intracranial coccidioidomycosis typically appears as a focal, well‐circumscribed granuloma of variable T2‐weighted intensity, typically appearing T1‐iso to mildly hypointense pre‐contrast and tends to exhibit strong contrast enhancement on T1‐weighted postcontrast sequences . In most cases, there is T2/T2‐fluid attenuated inversion recovery (FLAIR) hyperintensity surrounding the focal granuloma, often extensive throughout adjacent white matter, characteristic in appearance of perilesional vasogenic edema .…”

“…2 In most cases, there is T2/T2-fluid attenuated inversion recovery (FLAIR) hyperintensity surrounding the focal granuloma, often extensive throughout adjacent white matter, characteristic in appearance of perilesional vasogenic edema. 2 Cerebrospinal fluid is often abnormal if it can be safely obtained, and in many cases in our hospital, extensive vasogenic edema, a mass effect, and midline shifts may significantly increase the risk of obtaining a cerebrospinal fluid sample. Cerebrospinal fluid abnormalities commonly include a mixed cell pleocytosis with a predominance of neutrophils compared to mononuclear cells.…”

“…Common MRI imaging characteristics of central nervous system coccidioidomycosis have recently been described. 2 The purpose of this retrospective case series is to document an unusual variant appearance of intracranial coccidioidomycosis that, to the author's knowledge, has not yet been reported in the veterinary literature.…”