To date, our ability to predict the Recent progress in the genetics of endocrine tumors has resulted in an increased recognition of the genes that predispose to the development of pituitary adenomas in the context of multiple neoplasia syndromes (PA can be divided by size into microadenoma (< 1 cm) and macroadenoma (> 1 cm), the latter being responsible for 40% of the cases (Although only 0.2% of pituitary tumors are classified as malignant, defined by distant metastasis, they cause significant morbidity. On the top-left unenhanced and enhanced CT-images, the main differential diagnosis of the enhancing mass would include meningioma, pituitary adenoma and an aneurysm. On an unenhanced scan, approximately 70% of all pituitary microadenomas can be detected. These findings in a child are virtually pathognomonic for craniopharyngioma (perhaps with only a dermoid in the differential diagnosis). So again in order to analyse a sellar or parasellar mass on MRI we use the following anatomic approach: On the left another example of a pituitary macroadenoma. PA are associated with hormonal disturbances and compression symptoms like headaches, visual disturbances, and hypopituitarism due to mass effect. One of the most difficult differential diagnoses on CT is aneurysm versus meningioma. Coronal T1 and T2-weighted images and T1-weighted images before and after gadolinium. Craniopharyngioma is the third of the three pathologies derived from Rathke's cleft epithelium. The clinical picture of an intrasellar arachnoid cyst resembles that of a nonfunctional pituitary adenoma. The best images to see hamartomas on are enhanced sagittal T1-weighted MR images. Gliomas can occur in any part of the brain and the optic chiasm is a common location, particularly in patients with neurofibromatosis type 1. Further forward at the level of the orbits the optic nerve is abnormal on both sides. By definition, pituitary macroadenomas are adenomas over 10mm in size.
In general, all extra-axial masses , i.e.
Due to pituitary gland localization, they can put pressure on the optic chiasm and the pituitary stalk, as well as invading areas like the cavernous sinus and suprasellar area.Most of PA appear to occur sporadically, but about 5% occur due to an inherited condition, either isolated or as a part of an endocrine tumor syndrome.Several conditions are associated with a known genetic defect causing a predisposition to familial PA. Familial PA can be considered when at least two family members have a PA, but in cases of low penetrance seemingly simplex cases may have an inherited germline mutation, or “de novo” mutations can establish the potential for familial disease in further generations. On these axial images you can see the optic nerves and chiasm enhance after the administration of intravenous gadolinium. This is another example of a right-sided optic nerve glioma with enhancement after gadolinium. The following case concerns a 9-year-old male with a history of headache, nausea and vomiting.T2- and T1 weighted sagittal images of the same patient show a similar mass in the epiphysial area. Intrasellar location of schwannoma is extremely rare, although intracranial schwannomas account for up to 8% of all primary brain tumors. These consecutive coronal MR-images show the mass at the optic chiasm and the swollen optic nerves. The most common intracranial tumor in adults is the meningioma with 20% of occurring at the skull base. Pituitary adenomas (PA) are frequent benign monoclonal tumors representing approximately 15% of all primary intracranial tumors, being the third most frequent tumor type after meningioma and glioma (Scheithauer et al., 2006).Clinically overt pituitary adenomas are less commonly encountered, with recent studies reporting a population prevalence of ~80 cases per 100,000.A majority of patients with PAs have excellent long-term 15-year quality of life and survival Definitive metastasis occurs in less than 0.2% of PAs; tumors with rigorous evidence of extracranial metastasis are defined as pituitary carcinomas, thereby losing their standard designation as a benign tumor Much of the groundwork for defining an intermediate, higher-risk PA group was laid by studies pertaining to clinical disease recurrence/progression, tumor invasion, and histological tumor features. lntratumoral hemorrhage can vary from small focal hematomas (Figs. MR images of a similar small nodule suspended from the floor of the third ventricle. This is an example of a partially thrombosed aneurysm in the suprasellar cistern. Why did the aneurysm cause hyperprolactinemia and galactorrhea in this patient?
Rathke's cleft cysts can occur either in or above the sella turcica. Another common pathway of extension is laterally into the cavernous sinus. Because the pressure above the dura is larger than the pressure below, the macroadenoma then delivers itself into the sphenoid sinus. At medical school they teach you that a rare manifestation of a common lesion is more likely than a rare abnormality. Pituitary adenoma Summary . These T1, T2 and T1-weighted images after gadolinium demonstrate another Rathke's cleft cyst located in the pituitary gland. There is a large intrasellar and suprasellar mass with cystic and enhancing components as well as calcifications. A 39-yr-old man presented a 10-month history of visual disturbance and decreased libido.