pituicytoma is an extremely rare low - grade glioma that presumably arises from pituicytes , modified specialized glial cells located in the perivascular zones of the neurohypophysis . the rarity of this tumor has contributed to its poor characterization and difficulty in diagnosis . to date , only 51 cases of pituicytomas have been reported , mostly in pathology , neurosurgery , and radiology journals . to the best of our knowledge , we report a case of this rare tumor causing decreased vision and a junctional scotoma . when she presented to us , her visual acuity was 20/15 in the right eye , and she was able to count fingers at 2 feet in the left eye . automated perimetry showed a superotemporal defect in the right eye and central scotoma in the left eye , consistent with a junctional scotoma ( fig . magnetic resonance imaging ( mri ) of the brain with gadolinium revealed a solid , homogeneously enhancing sellar and suprasellar mass measuring 1.9  1.7  1.5 cm with compression of the optic chiasm ( fig . transsphenoidal surgery was attempted , but could not be achieved due to the highly vascular nature of the tumor . postoperative neuro - ophthalmologic examination showed that the visual acuity improved to 16/13 in the left eye . postoperative mri with gadolinium showed that the lesion had largely been resected , measuring 1.1  1.5  1.0 cm , with improvement in the displacement of the optic chiasm ( fig . postoperatively , the patient developed central hypothyroidism and hyperprolactinemia , and was placed on levothyroxine and cabergoline . given the subtotal resection of the tumor , treatment with radiation was discussed but we decided on observation . at her most recent follow - up 10 months after surgery , her ophthalmologic examination , mri results , and endocrinological status were stable . histopathological evaluation revealed a moderately cellular tumor composed of elongated cells with abundant eosinophilic cytoplasm arranged in a storiform pattern ( fig . there were no mitotic figures , necrosis , rosenthal fibers , or perivascular pseudorosette formation . immunohistochemical stains showed that the tumor was diffusely positive for glial fibrillary acidic protein ( gfap ) and focally positive for s-100 ( fig . these histological and immunohistochemical features raised the differential diagnosis of oncocytoma , granular cell tumor , and pituicytoma . electron microscopy of tumor cells showed no evidence of cytoplasmic accumulations of lysosomes or mitochondria , thus supporting the diagnosis of pituicytoma ( fig . the clinical presentation of pituicytomas is similar to that of other pituitary tumors , with patients typically presenting with visual or endocrinopathic symptoms . on neuroimaging , pituicytomas are characterized as a discrete , solid sellar mass that is isointense to the surrounding brain on t1-weighted mri and homogeneously enhancing after gadolinium administration [ 2 , 3 ] . preoperative diagnosis of pituicytomas is often challenging because of the lack of distinctive clinical or radiological features differentiating them from other pituitary tumors . for instance , our patient was initially suspected of having a pituitary adenoma . only after histological and immunohistochemical analysis was it determined to be a pituicytoma . pathologic analysis of pituicytomas shows elongated spindle cells arranged in interlacing fascicles with little or no nuclear atypia or mitotic activity . immunohistochemistry demonstrates s-100 and gfap positivity , but negative staining for synaptophysin , chromogranin a and b , and neurofilament . the histological and immunochemical profiles distinguish pituicytomas from other lesions of the sellar and suprasellar region , including pituitary adenoma and meningiomas . pituitary adenomas are synaptophysin reactive , frequently chromogranin positive , and negative for gfap and s-100 . in contrast to meningiomas , pituicytomas lack whorls , psammoma bodies , and nuclear pseudo - inclusions . differential diagnosis from other gfap - positive sellar lesions includes pilocytic astrocytomas and diffuse astrocytomas . pilocytic astrocytomas are composed of smaller , more elongated cells with coarse fibrillary processes and often have a myxoid background with scattered eosinophilic granular bodies and rosenthal fibers . other rare sellar lesions with a similar histological appearance are granular cell tumor and oncocytoma characterized on electron microscopy by intracytoplasmic accumulations of lysosomes ( granular cell tumor ) or mitochondria ( oncocytoma ) . surgical resection is the mainstay of treatment for pituityctomas . in the largest series to date , brat et al . reported that , among the 6 patient who underwent total surgical resection , no recurrences of the tumor occurred . recurrence after subtotal resection is common , with 4 of the 7 cases reported in the literature , among patients with a follow - up period of more than 6 months [ 4 , 6 , 7 , 8 , 9 ] . fractionated radiation therapy has been recommended for subtotal resection , but there is little data to suggest any benefit . this report adds to the rare cases of pituicytoma currently in the literature and is the first case to be reported in the ophthalmic literature . ophthalmologists should become familiar with the clinical , radiological , and histopathological features of this rare neoplasm as pituicytomas can cause significant visual symptoms .
pituicytomas are rare neoplasms of the sellar region . 
 we report a case of vision loss and a junctional scotoma in a 43-year - old woman caused by compression of the optic chiasm by a pituitary tumor . 
 the morphological and immunohistochemical characteristics of the tumor were consistent with the diagnosis of pituicytoma . 
 the tumor was debulked surgically , and the patient 's vision improved .