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2005 WHO histological classification of odontogenic tumours

The 2005 WHO histological classification of odontogenic tumours lays out a classification system for neoplasms and other tumours related to the odontogenic apparatus. At the time of writing (2016), it is still the most widely used classification system although a new revision is due to come up i...

Carcinoembryonic antigen

Serum carcinoembryonic antigen (CEA) is a cell-adhesive glycoprotein that was discovered in colorectal cancer in 1965, and is hence one of the oldest and most used tumour markers. Its name derives from its normal expression in fetoembryonic liver, gut and pancreas tissue. Normal range of CEA is...


Cerumen (or earwax) is a natural secretion produced by, and found within the external auditory canal (EAC). It has important roles as part of the first-line of defence of the ear from micro-organisms and optimising function of the tympanic membrane and EAC. Secretion Cerumen is secreted by the...

Charcot-Leyden crystals

Charcot-Leyden crystals consist of collections of bipyramidal crystalloid made up of eosinophilic membrane proteins, which occur in:  asthma other eosinophilic lung disease 2 certain cases of sinusitis (e.g. allergic fungal sinusitis) They may be detected in the sputum or sinus secretions wi...


A choristoma is simply a collection of microscopically normal cells or tissues in an abnormal location. This is different to a hamartoma which is derived only from local tissues. Examples include: adrenal choristoma (myelolipoma) nasopharyngeal choristoma facial nerve choristoma optic nerve...


P16 is a widely used immunohistochemical marker. It can be expressed in other neoplasms and in several normal human tissues. It can play an important role gynaecological malignancy and is a surrogate marker for HSIL's (high-grade squamous intraepithelial lesions). It has been applied to facilita...

Senile calcific scleral plaques

Senile calcific scleral plaques, also known as senile scleral plaques (SSP), are benign scleral degenerations common in elderly individuals. They are a common incidental finding on CT imaging. Epidemiology The prevalence of SSP increases with age, from ~2.5% at age 60, to 25% at age 80 years a...


Thyroseq® is an expanded gene classifier test designed for further evaluation of indeterminate thyroid nodules on fine needle aspiration (FNA). In particular, it is designed to further evaluate nodules that show atypia of undetermined significance / follicular lesion of undetermined significance...

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