Inflammatory myofibroblastic tumor of the orbit with associated enhancement of the meninges and multiple cranial nerves

Inflammatory myofibroblastic tumor (IMT), Tolosa-Hunt syndrome (THS), and idiopathic hypertrophic pachymeningitis (IHP) seem to be part of a spectrum of disorders that have diverse locations but similar histologic and imaging findings. We report a case of a 50-year-old man presenting with multiple progressive cranial nerves palsies with leptomeningeal cranial nerve enhancement on MRI (II, V1-V3, and X), orbital and infraorbital masses, prominence within the left cavernous sinus, and diffuse dural enhancement. Biopsies of the orbital lesion and infraorbital nerve revealed IMT. The patient's lesions, symptoms, and dural enhancement quickly improved with steroid administration and nearly resolved over multiple subsequent scans over the next few months. This case illustrates a rare case of pseudotumor mimicking a more aggressive appearance that would usually portend a case of malignancy. There is a potential association of IMT, THS, and IHP, which may have existed in a concomitant fashion in this patient. The case also describes the unique finding of enhancement of the cisternal segments of multiple cranial nerves (simulating leptomeningeal malignant involvement), which may be related to inflammatory perineural edema or ischemic neuropathy.

Metachronous, multicentric giant cell tumor of the sphenoid bone with histologic, CT, MR imaging, and positron-emission tomography/CT correlation

Giant cell tumor (GCT) of the sphenoid bone is a relatively rare entity and metachronous multicentric GCT of the sphenoid is even rarer; we are aware of only 3 previous cases in the literature. We describe here a tumor of the sphenoid bone that was identified 15 years after multiple resections of a GCT of the left inferior pubic ramus. Correlation is made between the histopathologic findings, MR imaging of the brain, CT of the head, and fusion positron-emission tomography (PET)/CT scan performed with fluorine-18 fluoro-2-deoxy-D-glucose (18F-FDG). This report is the first to describe the appearance of a GCT of the sphenoid bone on a fusion PET/CT examination. High metabolic activity in the base of the skull adjacent to the middle cranial fossa was demonstrated in a fashion similar to that of the known pelvic lesion. This case also demonstrates that the increased metabolic activity seen in a GCT of the sphenoid bone may be partially obscured by the adjacent physiologic high metabolic activity of the brain.

Tau suppression in a neurodegenerative mouse model improves memory function

Neurofibrillary tangles (NFTs) are the most common intraneuronal inclusion in the brains of patients with neurodegenerative diseases and have been implicated in mediating neuronal death and cognitive deficits. Here, we found that mice expressing a repressible human tau variant developed progressive age-related NFTs, neuronal loss, and behavioral impairments. After the suppression of transgenic tau, memory function recovered, and neuron numbers stabilized, but to our surprise, NFTs continued to accumulate. Thus, NFTs are not sufficient to cause cognitive decline or neuronal death in this model of tauopathy.

Spectrum of clinical and histopathologic responses to intracranial electrodes: from multifocal aseptic meningitis to multifocal hypersensitivity-type meningovasculitis

PURPOSE

We sought to characterize and compare the histopathologic and clinical changes elicited by subdural and depth electrodes in subjects undergoing epilepsy surgery evaluation.

METHODS

A retrospective review of clinical records, imaging and histopathologic studies of epilepsy surgery cases requiring subdural strips and depth electrodes for localization of epileptogenic tissue was performed between 1993 and 1999. Forty-nine subjects had a combination of subdural and depth, whereas 10 had depth electrodes only. Histopathologic changes were classified as mild, moderate, or severe based on the density, extent, and composition of the inflammatory infiltrate.

RESULTS

Subdural electrodes induced a clinical picture of transient aseptic meningitis; histopathologically, the infiltrates were moderate in degree in the majority (73%) and severe in the remainder (27%), with T cells and eosinophils infiltrating the cortex and arteriolar walls (hypersensitivity-type response). Depth electrodes alone caused minimal or no symptoms of meningeal irritation; the cellular response elicited by these electrodes was mild in five and moderate in the remaining five cases; severe inflammation was not observed in this group. Although the proportion of small clinically silent hematomas was larger in cases with depth (five of 59) compared with subdural electrodes (one of 49), microhemorrhages were considerably more numerous with subdural than with depth electrodes.

CONCLUSIONS

These results suggest that the spectrum of brain responses to foreign bodies is wide, ranging from self-limited physiologic to hypersensitivity-type reactions of varying severity. Subdural strips elicited more intense inflammation than did depth electrodes. The histopathologic extent of the reaction to either type of electrodes could not be precisely defined because of the retrospective nature of this study. History of allergy to latex or previous craniotomies are probable risk factors for the hypersensitivity-type reaction. Surgical outcome, excellent in the majority, was independent of the severity or type of inflammation, and there have not been neurologic or systemic sequelae.