Infundibulomas are tumors of the ependymal prolongation of the infundibulum (ventral hypothalamus) and involve the third ventricle, infundibulum and neurophypophysis. They may also arise from ependymal cells of the third ventricle.
Diagnosis is difficult as imaging with CT or MRI may not reveal a mass within the sella turcica, requiring hypophyseal biopsy or exploratory craniotomy.
Definitive diagnosis usually requires intraoperative or postmortem biopsy, verifying infundibular involvement with neoplastic changes. These tumors have the histological appearance of neurhypophyseal tissue, characterized by fusiform cells with long tapering processes occupying a highly vascular stroma. They resemble papillomas of the choroid plexus and hemangiomas and consist of cuboid epithelium either gathered into broad sheets or thrown into papillary projections.
A differential diagnosis would include lymphoma, hypothalamic-pituitary trauma, dorsally expanding cysts, inflammatory granuloma, lymphocytic hypophysitis, congenital malformations such as empty sella syndrome and neoplasms such as xanthogranuloma, craniopharyngioma, pituitary adenocarcinoma and metastatic tumors such as metastatic mammary carcinoma, lymphoma, malignant melanoma and pancreatic carcinoma.
Treatment has not been reported with this disease, although hypophysectomy would empirically be effective.
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