Intracranial pressure (ICP) is the pressure exerted by fluids such as cerebrospinal fluid (CSF) inside the skull and on the brain tissue. ICP is measured in millimeters of mercury (mmHg) and at rest, is normally 7–15 mmHg for a supine adult. The body has various mechanisms by which it keeps the ICP stable, with CSF pressures varying by about 1 mmHg in normal adults through shifts in production and absorption of CSF. Changes in ICP are attributed to volume changes in one or more of the constituents contained in the cranium. CSF pressure has been shown to be influenced by abrupt changes in intrathoracic pressure during coughing (which is induced by contraction of the diaphragm and abdominal wall muscles, the latter of which also increases intra-abdominal pressure), the valsalva maneuver, and communication with the vasculature (venous and arterial systems). Intracranial hypertension (IH), also called increased ICP (IICP) or raised intracranial pressure (RICP), is elevation of the pressure in the cranium. ICP is normally 7–15 mm Hg; at 20–25 mm Hg, the upper limit of normal, treatment to reduce ICP may be needed. Signs and symptoms of raised intracranial pressure
In general, symptoms and signs that suggest a rise in ICP include headache, vomiting without nausea, ocular palsies, altered level of consciousness, back pain, and papilledema. If papilledema is protracted, it may lead to visual disturbances, optic atrophy, and eventually blindness. The headache is classically a morning headache that may wake the person up.
All cells are positive with pancytokeratin and epithelial membrane antigen; only the luminal cells are positive with CK7; only the basal  cells are positive with CK5/6, p63, S100 protein. CD117 can be positive in either population. The cells are negative with chromogranin, synaptophysin and CK20. Diagnosis
The major diagnosis from which to separate ceruminous adenoma is ceruminous adenocarcinoma, which shows an infiltrative growth, pleomorphism, mitoses, necrosis, and lacks ceroid pigment granules. Other tumors which need to be excluded include a neuroendocrine adenoma of the middle ear (middle ear adenoma), paraganglioma, and endolymphatic sac tumor. Management
The tumors are usually removed in small pieces due to the anatomic confines of the area. Prognosis
Patients treated with complete surgical excision can expect an excellent long term outcome without any problems. Recurrences may be seen in tumors which are incompletely excised. Epidemiology
While there is a wide age range at clinical presentation (12–85 years), most patients come to clinical attention at 55 years (mean). There is no gender difference. References
Further reading
Lester D. R. Thompson; Bruce M. Wenig (2011). Diagnostic Pathology: Head and Neck: Published by Amirsys. Hagerstown, MD: Lippincott Williams & Wilkins. pp. 7:42–45. ISBN 978-1-931884-61-7.