The adductor pollicis muscle is a large triangular muscle anterior to the plane of the interossei that crosses the palm. It is the deepest muscle of the thenar eminence, and is one of the intrinsic muscles of the hand.
transverse head: 3rd metacarpal
oblique head: capitate an...
The adductor tubercle is a bony protuberance on the medial condyle of the femur and is located superior to the medial epicondyle. It demarcates the inferior most aspect of the medial supracondylar line. The adductor tubercle is the point of insertion for the adductor minimus and the hamstrings p...
Adenocarcinoma of the endometrium is the commonest histological subtype of endometrial cancer and accounts for up to 90% of such cases 1.
Histological sub types
serous type adenocarcinoma of the endometrium
clear cell type adenocarcinoma of the endometrium
Adenocarcinoma in situ, minimally invasive adenocarcinoma and invasive adenocarcinoma of the lung are relatively new classification entities which replace the now-defunct term bronchoalveolar carcinoma (BAC).
In 2011 the International Association for the Study of Lung Cancer (IASLC) and several...
Adenocarcinomas in situ (AIS) of the lung refer to a relatively new entity for a pre-invasive lesion in the lung. This entity partly replaces the noninvasive end of the previous term bronchoalveolar carcinoma. Adenocarcinoma in situ is defined as a localized adenocarcinoma of <3 cm that exhibits...
Adenocarcinoma of the appendix, also referred to as nonmucinous adenocarcinoma of the appendix, is an uncommon type of appendiceal epithelial neoplasm. Different from the appendiceal mucinous neoplasms, these tumors share similar epidemiology and pathology with colorectal adenocarcinoma.
Adenocarcinoma of the cervix is a histological subtype of carcinoma of the cervix.
Cervical adenocarcinoma is less common than squamous cell carcinomas (SCC) of the cervix, accounting for ~12.5% of all cervical cancer. Their proportionate prevalence is thought to be increasing an...
Adenocarcinoma of the lacrimal glands is rare, with few cases reported in the literature since it was first described in 1996 1. Primary adenocarcinoma of the lacrimal gland is extremely rare; only 9 cases have been reported in the literature 1,2. It can be classified into high- and low-grade ma...
Adenocarcinoma of the lung is the most common histologic type of lung cancer. Grouped under the non-small cell carcinomas of the lung, it is a malignant tumor with glandular differentiation or mucin production expressing in different patterns and degrees of differentiation.
This article brings...
Primary adenocarcinoma of the small bowel is about 50 times less common than colonic carcinoma.
Almost 50% of small bowel adenocarcinomas are found in the duodenum, especially near the ampulla. In the remaining cases, the jejunum is more commonly involved than the ileum1.
Adenocarcinoma of the urinary bladder is rare and accounts for only ~1% of all bladder cancers (90% are transitional cell carcinomas).
Metaplasia of urinary bladder induced by chronic irritation or infection can lead to adenocarcinoma. Pathological types of adenocarcinoma of the urin...
Adenoidal hypertrophy or enlargement in adults is much less commonly seen than in children. It is usually due to chronic infection or inflammation. HIV always needs to be excluded as a cause.
In general, the adenoid tonsils enlarge after birth, maximizing by 6 years old. Thereafter, ...
Adenoidal hypertrophy or enlargement in children is common and due to an increase in the size of the adenoids. For adenoidal enlargement in adults, which is much rarer and usually pathological, please see the separate article, adenoidal hypertrophy (adults).
Adenoid cystic carcinomas are a rare histological subtype of adenocarcinoma.
Adenoid cystic carcinomas are generally considered low grade 4. The tumors have a notable tendency for perineural spread.
They have a wide distribution and mainly occur in relation to the airways,...
Adenoid cystic carcinoma (ACC) of the lacrimal glands is an extraconal malignancy usually originating from the orbital lobe of the lacrimal gland.
It often presents with orbital pain and paresthesia, since this type of tumor is frequently associated with perineural spread...
Adenoid cystic carcinoma (ACC) of the lung is a type of non-small cell lung cancer. They are classified under lung carcinomas of the salivary gland type. Primary occurrence in the lung parenchyma is rare, while in the thorax they occur more commonly as adenoid cystic carcinoma of the tracheobron...
Adenoid cystic carcinoma (ACC) of the breast is a rare subtype of breast cancer.
They account for only 0.1-0.4% of all breast cancers.
The tumor demonstrates a strikingly characteristic microscopic pattern similar to that of adenoid cystic carcinoma of the salivary gla...
Adenoid cystic carcinoma (ACC) of the salivary glands is the second most common malignancy involving the minor salivary glands behind mucoepidermoid carcinoma and the second most common malignancy involving the parotid gland.
Adenoid cystic carcinomas arise more commonly in the minor...
Adenoid cystic carcinomas of the tracheobronchial tree are a type of low-grade tracheal tumor. They are considered to be the second most common primary tumor of the trachea.
They are usually first recognized in patients in their 4th and 5th decades. There is no recognized gender p...
Adenoid facies, also known as the long face syndrome, refers to the long, open-mouthed face of children with adenoid hypertrophy. Hypertrophy of the nasopharyngeal pad of lymphoid tissues (adenoids) is the most common cause of nasal obstruction in children. The mouth is always open because upper...
The adenoid tonsils, or often just simply the adenoids (also known as the nasopharyngeal or pharyngeal tonsils), are paired foci of lymphatic tissue located on the superoposterior wall of the nasopharynx and form part of Waldeyer's ring.
Adenolipoma of the thyroid gland (also known as a thyrolipoma or a thyroid hamartoma) is a rare, benign fat-containing thyroid lesion. These lesions are usually well encapsulated and are composed of varying degrees of follicular thyroid tissue (thyroid adenoma) and mature adipose tissue; the amo...
The adenoma-carcinoma sequence refers to a stepwise pattern of mutational activation of oncogenes (e.g. K-ras) and inactivation of tumor suppressor genes (e.g. p53) that results in cancer. An oncogene is a gene that has the potential to cause cancer. In tumor cells, these are often mutated or ex...
Adenoma malignum of the cervix, also referred to as minimal deviation carcinoma / minimal deviation adenocarcinoma, is considered a rare variant of cervical carcinoma. It is thought to represent ~1-3% of all cervical adenocarcinomas.
It can present in a wide age group (~25-70 year...
Adenomatoid odontogenic tumors are rare and differ from most other dentition related lesions in that they more frequently occur in the maxilla.
They are also seen more frequently in females, most frequently in the second decade of life.
They present as an e...
Adenomatoid tumors of the scrotum are benign, solid extratesticular lesions that can originate from the epididymis, tunica vaginalis, or spermatic cord (90% derived from the funiculus).
They are the most common extratesticular neoplasm, and most common tumor of the epididymis, and...
Adenomatous breast lesions are benign tumors which grow from glandular parenchyma. The breast is a conglomeration of various glandular tissues, hence they can be of several types.
apocrine adenoma of breast
pleomorphic adenoma of breast
Adenomatous endometrial hyperplasia is a type of endometrial hyperplasia.
The peak incidence is around 40-50 years of age.
Both endogenous and exogenous estrogen exposure are considered important factors in its etiology 1.
An adenomyoma is a focal region of adenomyosis resulting in a mass, which is difficult to distinguish from a uterine fibroid, although in general the degree to which the contour of the uterus is distorted is less marked in adenomyosis 2. Additionally, the 'mass' is poorly defined and blends with...
Adenomyomatosis of the gallbladder is a hyperplastic cholecystosis of the gallbladder wall. It is a relatively common and benign cause of diffuse or focal gallbladder wall thickening, most easily seen on ultrasound and MRI.
Adenomyomatosis is relatively common, found in ~9% of al...
Adenomyosis is a common uterine condition of ectopic endometrial tissue in the myometrium, sometimes considered a spectrum of endometriosis. Although most commonly asymptomatic, it may present with menorrhagia and dysmenorrhea. Pelvic imaging (i.e. ultrasound, MRI) may show characteristic findin...
An adenomyotic cyst is an extremely rare variation of cystic adenomyosis. The lesion consists of a large hemorrhagic cyst, which is partly or entirely surrounded by a solid wall. It can be entirely within the myometrium, submucosal, or subserosal and frequently is associated with symptoms of men...
Adenosis of the breast is a benign lobulocentric proliferative process in which lobules are enlarged and increased in number in addition to an increased number of glands within each lobule.
Pathologically subclassified into three main subtypes which include:
sclerosing adenosis of the breast
Adenosquamous cell carcinoma (ASC) of the cervix is a rare histological subtype of cervical carcinoma.
It has components of both cervical adenocarcinoma and cervical squamous cell carcinoma.
An adenosquamous histology appears to be an independent predictor of poor outcome...
Adenosquamous carcinoma of the endometrium is a rare histological sub type of endometrial cancer.
In general it occurs in a slightly younger group when compared with pure adenocarcinoma of the endometrium 4.
It contains both malignant glandular and malignant squamous components. Adenosquamous...
Adenosquamous carcinoma (ASC) of the lung is a rare type of non-small cell lung cancer.
It is thought to constituting 0.4-4% of cases non-small cell lung cancer.
The definition of adenosquamous carcinoma indicates a carcinoma showing components of adenocarcinoma and sq...
Adhesive atelectasis refers to the specific form of lung atelectasis that occurs due to the decrease or absence of pulmonary surfactant produced by type II pneumocytes. Without sufficient surfactant the alveoli collapse due to increased surface tension. It is most commonly seen in the neonate wi...
Adhesive capsulitis of the shoulder, also known as frozen shoulder, is a condition characterized by thickening and contraction of the shoulder joint capsule and surrounding synovium. Adhesive capsulitis can rarely affect other sites such as the ankle 8.
The incidence in the genera...
Adhesive otitis media is a form of chronic otitis media where there is an adhesion of medial ear structures as a result of chronic inflammation. There are often complete or partial adhesions between the thin retracted and atrophic pars tensa and the medial wall of the middle ear. Soft tissue deb...
Adie pupil (also known as tonic pupil) is caused by idiopathic degeneration of the ciliary ganglion, which sometimes occurs following a viral or bacterial illness. It is usually unilateral and typically affects young females 1.
Adie pupil represents a large dilated "tonic pupil", which does not...
Adie syndrome, also known as Holmes-Adie syndrome, is a rare neurological disorder.
Adie syndrome is a rare condition which is most commonly seen in young females in their fourth decade of life 2,3.
Patients most commonly present with a classic triad of:
The ADIR (ADduction and Internal Rotation) position relates to MR arthrography of the shoulder joint.
When added to a neutral-position shoulder protocol, MR arthrography in the ADIR position facilitates the diagnosis of labroligamentous lesions in patients with recurrent shoulder dislocations, ...
Adjacent level ossification is a complication of anterior cervical discectomy and fusion (ACDF) with anterior plate stabilization. It represents pathological heterotopic ossification of the soft tissues above or below the ends of the plate, contiguous with the adjacent vertebral body. It occurs ...
Adjacent segment degeneration is a common complication of spinal fusion occurring at the adjacent unfused level above or below the fused segment. It is usually encountered in the cervical spine or lumbar spine and occurs with an incidence of roughly between 2% and 4% per year 4.
Adnexa is a general term that refers to the accessory structures of an organ.
Adnexa have been described with:
hair follicles, sweat glands, nails
structures in the mastoid (posterior) wall of the middle ear, e.g. mastoid antrum, aditus ad antrum, mast...
The term adnexal torsion refers to torsion of the pelvic adnexal structures. This can encompass ovarian torsion + / - tubal torsion.
Adrenal abscesses are rare lesions affecting the adrenal glands and are usually encountered in the setting of disseminated infection.
Although cases have been described in both neonates and adults, no systematic literature is available on the epidemiology of adrenal abscesses.
Adrenal adenomas (a.k.a. adenomata) are the most common adrenal lesion and are often found incidentally during abdominal imaging for other reasons. In all cases, but especially in the setting of known current or previous malignancy, adrenal adenomas need to be distinguished from adrenal metastas...
The adrenal glands are supplied by three adrenal (suprarenal) arteries:
superior adrenal artery: arises from ipsilateral inferior phrenic artery
middle adrenal artery: arises from lateral side of abdominal aorta
inferior adrenal artery: arises from the ipsilateral renal artery
Adrenal calcification is not a rare finding in healthy asymptomatic people and is usually the result of previous hemorrhage or tuberculosis. Addison disease patients only occasionally develop calcification.
sepsis: Waterhouse-Friderichsen syndrome
An adrenal collision tumor or collision tumor of the adrenal gland is an uncommon condition where two histologically distinct tumors abut each other or are in close proximity in the same adrenal gland.
Collision tumors have been reported in nearly every organ, for example, collision ...
Primary adrenal cortical carcinoma is a highly malignant but rare neoplasm. It may present as a hormonally active or an inactive tumor.
Although men and women are affected equally, functioning tumors are more common in females, who are also more likely to have an associated endoc...
Adrenal cysts are rare lesions and are commonly incidental findings.
Adrenal cysts are reported to be rare with an incidence of <1% 1.
Patients can present with pain or swelling, although a significant portion (~40%) are incidental findings 1,3.
The adrenal (suprarenal) glands (often shortened to just the adrenals) are paired organs of the endocrine system, often asymmetric in shape.
Each gland is enclosed in the perirenal fascia and each has a body and two limbs: a medial limb and a lateral limb. However, the right adr...
Adrenal gland trauma most commonly results from blunt force trauma.
Adrenal gland trauma is present on 1-2% of CT imaging in blunt trauma although the occurrence is thought to be much higher as injury has been demonstrated at 28% in one autopsy series 1-4.
The right adrenal glan...
Despite its small size, the adrenal gland is affected by a relatively large number of neoplastic entities:
adrenal cortical carcinoma
adrenal lesions: for a more general list of...
Adrenal hemangiomas are rare benign tumors that are usually incidentally identified (one example of an adrenal incidentaloma). Its significance mainly relates to the difficulty in differentiation from other malignant lesions.
Although these can be found at any age, they are most ...
Adrenal hemorrhage can result from a variety of traumatic and non-traumatic causes. When unilateral, it is often clinically silent. In contrast, bilateral adrenal hemorrhage can lead to catastrophic adrenal insufficiency.
The large majority of patients with unilateral adr...
Adrenal hyperplasia refers to non-malignant growth (enlargement) of the adrenal glands and is a rare cause of ACTH-independent Cushing syndrome, with unilateral adrenal cortical adenomas being the commonest. Approximately 20% of Conn syndrome cases are secondary to adrenal hyperplasia. In diffus...
Adrenal insufficiency refers to inadequate secretion of corticosteroids (glucocorticoids and mineralocorticoids).
It may occur from partial or complete destruction of the adrenal cortex, in which case it is termed primary adrenal insufficiency (also known as Addison disease). Secon...
Adrenal lesions cover a broad spectrum from benign to neoplastic entities. Due to increased use of cross-sectional imaging they are frequently detected as incidental lesions (incidentalomas). If found incidentally, please refer to the Management of Incidental Adrenal Masses: American College of ...
An adrenal lipoma is an extremely rare macroscopic fat containing adrenal lesion. with only a handful of cases described in literature 1.
Like other lipomas elsehwre in the body, they are benign tumors of mesenchymal origin that contain mature fatty tissue and are surrounded by a fib...
Adrenal lymphangiomas, also known as cystic adrenal lymphangiomas, are rare, benign cystic adrenal lesions.
Adrenal lymphangiomas are extremely rare; prevalence is estimated at 0.06% 8. They can occur at any age, with a peak incidence between the 3rd and 6th decades of life. Accor...
Adrenal lymphoma can refer to
primary adrenal lymphoma: rare
can be bilateral in around 70% of cases 1
secondary involvement of the adrenal glands with lymphoma: more common
Can be variable and can include adrenal insufficiency, worsening general state, weight loss an...
Adrenal metastases are the most common malignant lesions involving the adrenal gland. Metastases are usually bilateral but may also be unilateral. Unilateral involvement is more prevalent on the left side (ratio of 1.5:1).
They are present at autopsy in up to 27% of patients with ...
Adrenal myelolipomas are rare, benign and usually asymptomatic tumors of the adrenal gland characterized by the predominance of mature adipocytes.
On imaging, they usually present as large masses with a variable amount of fat-containing components.
Rare tumors with estimated aut...
Adrenal pseudocysts account for ~40% of adrenal cysts and are more likely than simple adrenal cysts to be symptomatic.
Pseudocysts do not have an epithelial lining and typically arise after an episode of adrenal hemorrhage. There is an ~7% association with malignancy (e.g. from hemor...
An adrenal teraoma is a very rare adrenal lesion. They account for around 0.7% of all primary adrenal tumors. As with teratomas in general, they are composed of mature tissues arising from more than one germinal layer.
They classically demonstrate a large fatty/lipomatous...
Tuberculous adrenalitis is the result of adrenal mycobacterium tuberculosis (TB) infection. Its incidence has decreased in the western world with the declining incidence of tuberculosis.
As the tuberculous infection causes destruction of the adrenal cortex, primary adrenal insufficie...
The venous drainage of the adrenal (suprarenal) glands is typically comprised of a single vein draining each adrenal gland. Like the gonadal veins each side drains differently:
left suprarenal vein drains into the left renal vein 1.
right suprarenal vein drains directly into the inferior vena ...
Adrenal vein sampling (AVS) is a procedure where blood is collected from the adrenal veins via catheter to confirm autonomous hormone production, if it is unilateral or bilateral, and to guide further treatment.
Adrenal vein sampling is commonly performed in primary aldosteronism, b...
Adrenal washout can be calculated using the density value of an adrenal mass on non-enhanced, portal venous phase and 15 minutes delayed CT scans (density measured in Hounsfield units (HU)). It is primarily used to diagnose adrenal adenoma.
[(HUportal venous phase) - (HUdelaye...
Adrenocorticotropin independent macronodular adrenocortical hyperplasia (AIMAH) is considered a rare form of macronodular adrenal hyperplasia. It is an uncommon cause of primary adrenal hypercortisolism.
Patients with AIMAH tend to present 10 years earlier on average than...
Adrenomyeloneuropathy is a form of X-linked adrenoleukodystrophy characterized by pronounced involvement of the spinal cord with only minor involvement of the cerebral white matter.
Clinical presentation depends on whether or not there is also cerebral involvement.
Adult acquired flatfoot disease is a common condition that results in foot pain and disability.
Most commonly affects middle-aged and elderly females 1.
Adult acquired flatfoot disease is a combination of:
flattened medial arch (pes planus)
Cervical lymphadenopathy in an adult can result from a vast number of conditions. They include:
from head and neck tumors
other neoplastic lesions
Adult chest radiograph common exam pathology is essential to consider in the build up to radiology exams. The list of potential diagnoses is apparently endless, but there are some favorites that seem to appear with more frequency.
When dealing with the adult chest radiograph in the exam setting...
A chest radiograph in the exam setting may contain a vast variety of pathology. However, consider the history and correlate the likely diagnoses that may be demonstrated on film. Furthermore, check your review areas to ensure that the abnormality isn't at the corner of the film.
The adult chest radiograph pathology checklist is just a pathology checklist of things not to miss when reviewing a chest radiograph, especially in the exam setting.
standard review areas
below the diaphragm
right descending pulmonary artery (like a l...
There are a number of adult chest radiograph set-pieces. These are based on common patterns of disease that are seen on chest radiographs. Make sure that you have relevant differentials for these appearances and a quick oral set-piece for them when they come up.
Adult cystic renal disease comprises multiple distinct hereditary and non-hereditary disease processes.
adult polycystic kidney disease (APCKD), a.k.a. autosomal dominant polycystic kidney disease (ADPCKD)
medullary cystic kidney disease
von Hippel-Lindau dis...
Whenever you look at an adult elbow x-ray, review:
Check the anterior humeral line:
drawn down the anterior surface of the humerus
should intersect the middle 1/3 of the capitellum
if it doesn't, think distal humeral fracture
Adult granulosa cell tumor of the ovary is a type of ovarian sex cord / stromal tumor. They are by far the most frequent subtype of granulosa cell tumors of the ovary (95%) and are commoner than the juvenile granulosa tumor of the ovary.
Approximately two-thirds of this subtype ar...
Adult-onset leukodystrophies are uncommon compared to those that present in childhood and in most instances are a delayed and atypical presentation of conditions more common in childhood. They are important differential considerations when assessing adults with white matter diseases.
Adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP), also known as hereditary diffuse leukoencephalopathy with spheroids (HDLS) and pigmentary orthochromatic leukodystrophy (POLD), refers to a rare inherited autosomal dominant disease characterized by an adult-onset l...
Adult-onset Still disease is a rare multisystem inflammatory disorder.
Still disease in adults is rare affecting around 1.5 per 100,000 people, it occurs in a bimodal distribution with one peak around the age of 15-25 years old and another around the age of 35-45 years old 1. It a...
Adventitial bursae are those bursae that develop later in life in response to pressures developed as a result of acquired bony prominences or deformities 1. These bursa can become inflamed resulting in adventitious bursitis.
Adventitious or adventitial bursitis refers to inflammation associated with adventitious bursae.
Adventitious bursae are not permanent native bursae. They can develop in adulthood at sites where subcutaneous tissue becomes exposed to high pressure and friction.
Adynamic ileus is the failure of passage of enteric contents through the small bowel and colon that are not mechanically obstructed. Essentially it represents the paralysis of intestinal motility.
Patients may be asymptomatic or present with symptoms similar to a mechanic...
Pathologic aerophagia is a rare condition caused by excessive and inconvenient air swallowing. It is a self-limiting condition affecting mainly children exposed to high grades of stress but can be a persistent problem in children with psychiatric or neurological disorders.
Afferent loop syndrome is an intermittent partial or complete mechanical obstruction of the afferent limb of a gastrojejunostomy.
The syndrome classically refers to obstruction of the upstream limb of a side-to-side gastrojejunostomy but has also been used to refer to the biliopancreatic limb o...
Aflatoxins are naturally-occurring mycotoxins that are produced by Aspergillus species, especially Aspergillus flavus. They are acutely toxic and carcinogenic.
High-level aflatoxin exposure can result in acute aflatoxicosis with acute hepatic necrosis, leading to cirrhosis, and ...
Agatston score is a semi-automated tool to calculate a score based on the extent of coronary artery calcification detected by an unenhanced low-dose CT scan, which is routinely performed in patients undergoing cardiac CT. Due to an extensive body of research, it allows for early risk stratificat...