OBJECT
Xanthogranulomas are rare inflammatory masses most often found in the skin and eye. The incidence of intracranial xanthogranulomas is 1.6%–7%, with those found in the sellar and parasellar region being exceedingly rare and their etiology controversial. Sellar and parasellar xanthogranulomas are rarely reported in the western hemisphere, and their incidence in Western countries is unknown.
METHODS
A prospectively acquired database of all endonasal endoscopic transsphenoidal surgeries performed at Weill Cornell Medical College was queried. Patients with histologically confirmed xanthogranulomas who were diagnosed and treated between 2003 and 2013 were included in the study. Patient history, demographic data, histological findings, and surgical approach were also evaluated.
RESULTS
A total of 643 endonasal endoscopic procedures had been performed at the time of this study. Four patients (0.6%) were identified as having a histologically confirmed xanthogranuloma of the parasellar region, compared with an incidence of 6.7% for craniopharyngioma (CP) and 2% for Rathke cleft cyst (RCC). The most common symptom was visual loss, followed by headache. Preoperative diagnosis was CP in all cases. All patients underwent extended endonasal endoscopic transsphenoidal surgery with gross-total resection. Two patients developed panhypopituitarism after surgery. There were no CSF leaks. The mean follow-up was 61 months, at which time there were no recurrences. The key histological features differentiating xanthogranulomas from CPs were accumulation of foamy macrophages, multinucleated foreign body giant cells, cholesterol clefts, and hemosiderin deposits without stratified squamous epithelium. These histological features appear commonly as part of the spectrum of a secondary inflammatory response in an RCC.
CONCLUSIONS
Parasellar xanthogranulomas most closely approximate CPs clinically but pathological evidence may suggest an RCC origin. Gross-total resection can be achieved through extended endonasal endoscopic transsphenoidal approaches, and is curative.
In vivo calcium imaging is an incredibly powerful technique that provides simultaneous information on fast neuronal events, such as action potentials and subthreshold synaptic activity, as well as slower events that occur in the glia and surrounding neuropil. Bulk-loading methods that involve multiple injections can be used for single-cell as well as wide-field imaging studies. However, multiple injections result in inhomogeneous loading as well as multiple sites of potential cortical injury. We used convection-enhanced delivery to create smooth, continuous loading of a large area of the cortical surface through a solitary injection site and demonstrated the efficacy of the technique using confocal microscopy imaging of single cells and physiological responses to single-trial events of spontaneous activity, somatosensory-evoked potentials, and epileptiform events. Combinations of calcium imaging with voltage-sensitive dye and intrinsic signal imaging demonstrate the utility of this technique in neurovascular coupling investigations. Convection-enhanced loading of calcium dyes may be a useful technique to advance the study of cortical processing when widespread loading of a wide-field imaging is required.
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