Pituitary Mass Effects
Note: pituitary tumors are almost always a benign adenoma. Pituitary adenomas are very common -approximately 1 in 6 individuals. These are usually asymptomatic and are found incidentally. Symptomatic pituitary adenomas that require treatment are much less common and affect approximately 1 in 1000 individuals.
Note: typically (but not always) the anterior hormones will be lost in the following order; GH, LH, FSH, TSH, ACTH, PRL. This order (with the exception of prolactin) is the order of least-essential to most-essential hormones needed for survival. A good mnemonic to remember the order the hormones are is, “Go Look For The Adenoma Please”.
Note: for pituitary masses of all sizes, it is important to determine whether the pituitary tumor is secreting (70%) or non-secreting (30%) as secreting tumors can be targeted with medication. The most common secreting tumors secrete prolactin (most common), growth hormone, and ACTH.
Authors: Chris Oleynick Reviewers: Amyna Fidai Laura Byford-Richardson Joseph Tropiano Hanan Bassyouni* * MD at time of publication
Microadenoma Small size is unlikely to cause mass effects (<10mm on MRI) Asymptomatic Macroadenoma Large size may press on surrounding structures, causing mass effects Headaches Stretching of the meninges Activation of mechanoreceptors Nausea and (>10mm on MRI) vomiting Giant adenoma Extension into hypothalamus —1■• Damage to hypothalamic cells Hypothalamic (>40mm on MRI) dysfunction Obstruction of dopamine Superior tumor growth Impingement of the optic chiasma Bitemporal Loss of pituitary hemianopsia hormones ICP Suprasellar extension Occlusion of ventricles Obstruction of CSF Flow Hydrocephalus Lateral tumor growth Impingement of cranial nerves 3, 4, 5 (V1/V2) and 6 4 Pituitary stalk impingement Diplopia Inferior tumor growth Erosion into sphenoid sinus CSF leak into throat Post-nasal Obstruction of ADH drip Communication between sinus and brain Migration of bacteria from sinus flora Hyper-Diabetes Meningitis prolactinemia insipidus
Published October 1 2017 on www.thecalgaryguide.com