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16 results found

Parathyroid proliferative disease

Parathyroid proliferative disease is the collective term for a spectrum of parathyroid disorders 1: parathyroid adenoma parathyroid carcinoma parathyroid atypical adenoma: controversial entity parathyroid hyperplasia primary chief cell hyperplasia primary water-clear cell hyperplasia (rare...

Bethesda classification system for thyroid fine needle aspirates

Bethesda classification system for thyroid fine needle aspirates comprises six categories of pathological reporting of thyroid FNA, with each category linked to a malignancy risk. The categories are: category I: non diagnostic category II: benign category III: atypia of undetermined significa...

WHO classification of eye tumors

The World Health Organizatiοn (WHO) classification of eye tumors is a widely used pathologic classification system of neoplasms of the orbit. The current revision, part of the 4th edition of the WHO series, was published in 2018 and is reflected in the article below 1. Classification Tumors of...

Hurthle cell

Hurthle cells are a type of oncocyte arising from thyroid follicular epithelial cells. Terminology The term Hurthle cell is now officially discouraged as the cells discovered by Hurthle were actually parafollicular C cells 5. Pathology Under microscopy, Hurthle cells are larger than typical ...

Hernia (general)

Hernias (or herniae) are a common pathological entity, in which an anatomical structure passes into an abnormal location via an opening. The opening may be a normal physiological aperture (e.g. hiatus hernia: stomach passes through the diaphragmatic esophageal hiatus) or pathological. Iatrogeni...


The term lamellated (or laminated which means the same thing) is a radiopathological term used to describe the layered appearance of many calculi, including those of the renal tract, the salivary glands, and the biliary tree. The internal structure of these calculi has been likened to that of an...


Cerumen, also known as 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 defense of the ear from micro-organisms and optimizing function of the tympanic membrane and EAC. Secretion Cerumen is secre...


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 (...


Iodine (chemical symbol I) is one of the trace elements. Its biological importance is its central place in the physiology of the thyroid gland and, in radiology, as the key chemical constituent of most of the radiographic, fluoroscopic, and CT contrast media. Chemistry Basic chemistry Iodine ...


CDKN2A (cyclin-dependent kinase inhibitor 2A) is a tumor suppressor gene that encodes for the p16 protein, involved in the CDK4/6–RB1 cell-cycle pathway 5.  p16 is a widely used immunohistochemical marker indicating expression of the cell cycle protein, which is upregulated by human papillomavi...

Gene expression classifier

A gene expression classifier (GEC) test is a developing technology in the analysis of indeterminate thyroid nodules, using cells from a fine needle aspiration. The most common commercially available GEC in the United States is known as AFIRMA. The test is designed to use molecular markers to he...

Sinonasal polyposis

Sinonasal polyposis refers to the presence of multiple benign polyps in the nasal cavity and paranasal sinuses. Epidemiology It is most commonly encountered in adults and rare in children. Polyps are the most common expansile lesions of the nasal cavity 8. Associations Conditions known to be...

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...

WHO classification of odontogenic and maxillofacial bone tumors

The WHO classification of odontogenic and maxillofacial bone tumors, last published in 2017, is a subset of the WHO classification of head and neck tumors (4th edition), which lays out a histological classification system for neoplasms and other tumors related to the odontogenic apparatus. Clas...

Psammoma bodies

Psammoma bodies are round microscopic calcific collections. It is a form of dystrophic calcification. Necrotic cells form the focus for surrounding calcific deposition. They have a lamellated concentric calcified structure, sometimes large enough to be seen on CT.  Psammoma bodies are found in ...


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...

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