Articles

Articles are a collaborative effort to provide a single canonical page on all topics relevant to the practice of radiology. As such, articles are written and edited by countless contributing members over a period of time. A global group of dedicated editors oversee accuracy, consulting with expert advisers, and constantly reviewing additions.

568 results found
Article

Lymphoma of the uterine cervix

Lymphoma of the uterine cervix is generally uncommon and when it does occur tends to present as cervical involvement with added background multi-organ disease rather than isolated primary cervical lymphoma 1. It is often considered part of the spectrum of uterine lymphoma. Epidemiology In the ...
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Lymphoma (staging)

There are a number of lymphoma staging systems for both Hodgkin lymphoma and non-Hodgkin lymphoma including the Ann Arbor classification, Cotswolds-modified Ann Arbor classification, the Lugano classification and the most current LYRIC classification Evolution of lymphoma staging and treatment ...
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Lymphomatoid granulomatosis (CNS manifestations)

Lymphomatoid granulomatosis of the central nervous system is uncommon, but represents the second most common site of involvement in patients with systemic lymphomatoid granulomatosis, after the lungs, which are most commonly involved. It is considered one of the immunodeficiency-associated CNS l...
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Male breast cancer

Male breast cancer is exceptionally rare and only accounts for less than 0.25% of male malignancies and ~0.5-1% of all breast cancer (both genders). The diagnosis is sometimes delayed due to the patient's hesitancy to seek advice. Workup from a radiological point of view is the same as for women...
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Male breast disease

Male breast disease includes a wide spectrum of conditions. Many conditions and entities that affect the female breast may also affect the male breast.  Pathology Malignant male breast cancer lymphoma dermatofibrosarcoma Benign gynaecomastia pseudogynaecomastia: fat deposition within the...
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Malignant biliary tract obstruction (summary)

This is a basic article for medical students and other non-radiologists Malignant biliary tract obstruction (MBTO) represents a group of conditions that cause obstructive jaundice. While most examples are the result of pancreatic head cancers, other malignancies may be causative. Reference art...
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Malignant fibrous histiocytoma

Malignant fibrous histiocytoma (MFH), which has more recently been classified as pleomorphic undifferentiated sarcoma (PUS) and formerly known as fibrosarcoma, is considered the most common type of soft tissue sarcoma. It has an aggressive biological behaviour and a poor prognosis. As in the ma...
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Malignant melanoma

Malignant melanoma is a malignant neoplasm that arises from melanocytes (or cells that derive from melanocytes).   Pathology Melanocytes predominantly occur in the basal layer of the epidermis and most melanomas, therefore, arise in the skin.  However, melanocytes do occur in other locations a...
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Malignant pleural disease

Malignant pleural disease usually heralds a poor prognosis, whether it represents a primary pleural malignancy or metastatic involvement.  Clinical presentation Clinical presentation is variable. Patients may be asymptomatic or have pleuritic pain. If associated with a sizeable pleural effusio...
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Malignant pleural mesothelioma (staging)

A number of staging systems have been described for staging of malignant pleural mesothelioma. Below is the International Mesothelioma Interest Group TNM staging system. TNM T - Tumour Tx: primary tumour cannot be assessed T0: no evidence of primary tumour T1a potentially resectable only ...
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Malignant transformation

Malignant transformation is the term given to the process whereby either normal, metaplastic, or benign neoplastic tissue, becomes a cancer. The process usually occurs in a series of steps and the affected tissue gradually accumulates the genetic mutations that express a malignant phenotype. The...
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MALT lymphoma

Mucosa-associated lymphoid tissue (MALT) lymphoma, also called extranodal marginal zone B-cell lymphoma, is a type of low-grade extranodal lymphoma.  Epidemiology MALT lymphoma represents ~7.5% of non-Hodgkin lymphomas. The average age of presentation is 60 years with a slight female predomina...
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Mandibular lesions

Mandibular lesions are myriad and common. The presence of teeth results in lesions that are specific to the mandible (and maxilla) and a useful classification that defines them as odontogenic or non-odontogenic. While it may often not be possible to make a diagnosis on imaging alone, this classi...
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Mantle cell lymphoma

Mantle cell lymphoma (MCL) is a type of non-Hodgkin lymphoma (NHL) and accounts for ~5% of all NHL. It is a malignant neoplasm of virgin B cells that closely resemble normal mantle zone B cells surrounding germinal centres. Epidemiology They occur in older adults (mean age ~60 years). There is...
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Masaoka staging system of thymoma

The Masaoka staging system is commonly adopted for thymomas 1-3, and is the most important determinant of survival following surgical resection 4: stage I: intact thymic capsule stage II: capsular invasion into adjacent mediastinal fat or pleura stage III: macroscopic invasion into adjacent o...
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Maxillary antral carcinoma

Maxillary antral carcinomas are an uncommon head and neck malignancy. They usually present late despite growing large since they remain confined to the maxillary sinus and produce no symptoms. Epidemiology Most commonly affects patients over 45 and has a strong male predilection (M:F = 5:1). M...
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Mediastinal lymph node enlargement

Mediastinal lymph node enlargement can occur from a wide range of pathologies. It may occur on its own or in association with other lung pathology. Terminology Although mediastinal lymphadenopathy is used interchangeably - by some - with "mediastinal lymph node enlargement", they are not synon...
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Meningeal haemangiopericytoma

Meningeal haemangiopericytomas are rare tumours of the meninges, now considered to be aggressive versions of solitary fibrous tumours of the dura, often presenting as a large and locally aggressive dural mass, frequently extending through the skull vault. They are difficult to distinguish on ima...
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Meningeal melanocytoma

Meningeal melanocytomas are rare benign primary melanocytic tumours of the CNS that are derived from leptomeningeal melanocytes. They can occur anywhere along the neuraxis but are most commonly found in the spinal canal near the foramen magnum, as well as the posterior fossa, Meckel’s cave, or a...
Article

Mesothelioma

Mesothelioma, also known as malignant mesothelioma, is an aggressive malignant tumour of the mesothelium. Most tumors arise from the pleura, and so this article will focus on pleural mesothelioma. Given the presence of the mesothelium in different parts of the body, mesothelioma can arise in va...
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Mesothelioma (summary)

This is a basic article for medical students and other non-radiologists. Pleural mesotheliomas are malignant tumours of the lining of the lungs. There is a strong association with asbestos exposure. Reference article This is a summary article; read more in our article on mesothelioma. Summar...
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Metastases to testis

Metastases to testis are a rare cause of a testicular mass and may be bilateral in up to 15% of patients.  Epidemiology Metastases to the testes are apparent in ~0.04% of autopsy studies in patients with known malignancy. The average age is 57 years, much older than the primary age for primary...
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Metastases to the breast

Metastases to the breast from non-mammary primary tumours are uncommon and account for 0.5-2.0% of all breast malignancies.  Clinical presentation Metastases do not tend to cause retraction of the skin or nipple. Metastatic lesions are much more likely to be multiple or bilateral than primary ...
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Metastases to the ovary

Metastases to the ovary are relatively common with a documented incidence of 5-30% of all malignant ovarian masses. These may be incorrectly grouped under Krukenberg tumours, which are signet cell containing tumours that form only 30-40% of all ovarian metastases.   Clinical presentation Ther...
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Metastases to the thymus

Metastases to the thymus are rare, although they are probably under reported due to lack of symptoms.  Pathology Varied primary tumours have been reported to metastasise to the thymus 1,2: breast cancer lung cancer ovarian cancer colorectal carcinoma gastric cancer prostate cancer testi...
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Metastases to the thyroid

Metastases to the thyroid are an uncommon cause of thyroid malignancy.  Epidemiology Metastases to the thyroid represent 1.4-3% of all malignancies 5. In autopsy series, the incidence is ~10% (range 2-24%) 1,5.  Pathology The most common sites of primary malignancy include (note these will v...
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Metastases to the vagina

Metastases to the vagina are more common than primary vaginal malignancies and account for >80% of vaginal tumours. Pathology Metastases usually spread from contiguous sites most commonly, with lymphatic and hematogenous metastases also recognised. Tumors that metastasise to the vagina includ...
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Minor salivary gland tumours

Minor salivary gland tumours are a subtype of salivary gland tumours originating from the minor salivary glands, which are found in the lips, tongue, hard palate, and the mucosa of the oropharynx and larynx, among other locations. Epidemiology MSGTs account for ~15% of all salivary gland tumou...
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MRI protocols

MRI protocols are a combination of various MRI sequences, designed to optimally assess a particular region of the body and/or pathological process. There are some general principles of protocol design for each area. However, the specifics of a protocol are dependent on MRI hardware and software...
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MRI reporting guidelines for cervical cancer

MRI reporting guidelines for cervical cancer help maintain uniformity of reports and assessment of important imaging staging criteria. Tumour size The tumour should be measured in three orthogonal planes. Tumours with a maximum diameter >4 cm are usually not amenable to primary radical surgery...
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Multilocular cystic renal tumour

Multilocular cystic renal tumours (MCRT) are rare benign renal neoplasms occurring in a bimodal age distribution, involving young children and adults in the 4th and 5th decades. For logical reasons, this article will discuss together the two ends of the spectrum of this disease, cystic partiall...
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Multiple cystic neck lesions (differential)

The differential diagnosis for multiple cystic neck lesions is different to that for a solitary cystic neck mass. Differential diagnosis Cystic neck lesions are seen in: necrotic metastatic SCC nodes: older patient, M>F papillary thyroid carcinoma metastases: usually a younger patient, F>M ...
Article

Multiple myeloma

Multiple myeloma is the most common primary malignant bone neoplasm in adults. It arises from red marrow due to monoclonal proliferation of plasma cells and manifests in a wide range of radiographic abnormalities. Multiple myeloma remains incurable. Terminology Four main patterns are recognise...
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Muscle lymphoma

Muscle lymphoma is a rare manifestation of lymphoma. Epidemiology Muscle lymphoma is rare, representing <2% of all lymphomas. The average age of presentation is 70 years 1. Clinical presentation Focal swelling and/or pain along with B-type symptoms 2. Any muscle can be involved but most comm...
Article

Musculoskeletal angiosarcoma

Musculoskeletal angiosarcomas, (along with haemangiopericytomas and haemangioendotheliomas) are tumours that arise from vascular structures. They are typically difficult to distinguish from one another on imaging alone. Angiosarcomas, are the most aggressive of the three, frequently having meta...
Article

Mycosis fungoides

Mycosis fungoides (MF), also known as cutaneous T-cell lymphoma, is a type of malignant T-cell lymphoma that primarily involves the skin.  Epidemiology In the United States, it is more common in males and African Americans. In Europe, it accounts for ~6% of all non-Hodgkin lymphomas. It is rar...
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Myelodysplastic syndrome

Myelodysplastic syndromes (MDS) are a heterogeneous group of clonal haematological stem cell disorders. It has sometimes been referred to as a preleukaemia or a preleukaemic condition. Epidemiology Its overall incidence is thought to be around 3.3 per 100,000. The incidence in patients older t...
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Myeloid sarcoma

Myeloid sarcoma (also called granulocytic sarcoma, chloroma, and extramedullary myeloid tumour) is a rare neoplasm comprised of myeloid precursor cells. Epidemiology It is typically seen is in children with ~60% occurring in individuals less than 15 years of age. There is no recognised gender ...
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Myeloproliferative disorder

Myeloproliferative disorders (MPDs) are a diverse group of conditions that are characterised by the overproduction of red cells, white cells and/or platelets in bone marrow. There are numerous conditions considered in this group but the most common are:  myelofibrosis polycythaemia vera essen...
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Myoinositol peak

Myoinositol is one of the compounds images with MR spectroscopy (MRS) at both 1.5 T and 3 T and is seen to resonate at 3.5 ppm chemical shift (right of the choline peak).  Myoinositol is a precursor of both phosphatidylinositol (the major inositol-containing phospholipid) and of phosphatidylino...
Article

Nasopharyngeal carcinoma

Nasopharyngeal carcinomas (NPC) are the most common primary malignancy of the nasopharynx. It is of squamous cell origin, some types of which are strongly associated with the Epstein-Barr virus (EBV). Epidemiology Nasopharyngeal carcinoma accounts for ~70% of all primary malignancies of the na...
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Necrobiotic xanthogranuloma

Necrobiotic xanthogranulomas are a rare form of cutaneous non-Langerhans cell histiocytosis. Epidemiology The condition occurs mostly in older adults 2. Clinical presentation Patients demonstrate cutaneous papules that develop into large, firm plaques, papules and nodules, which are often ye...
Article

Neonatal neuroblastoma

  Neonatal neuroblastoma is a type of congenital neuroblastoma, an embryonal tumour arising from the sympathetic nervous system. In the majority of cases (45%), the tumour is localised in the adrenal gland.  Epidemiology Neonatal neuroblastoma accounts for less than 5% of all cases and carrie...
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Neoplasms of the spinal canal

Neoplasms of the spinal canal encompass a range of tumours which arise from or involve the spinal cord, theca and spinal nerves. Pathology These can be divided according to the tissue/structure of origin within the spinal canal. Tumours of vertebral bodies are discussed separately: see vertebr...
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Nephroblastomatosis

Nephroblastomatosis refers to diffuse or multifocal involvement of the kidneys with nephrogenic rests (persistent metanephric blastema). Epidemiology Nephrogenic rest are found incidentally in 1% of infants. Pathology Nephrogenic rests are foci of metanephric blastema that persist beyond 36 ...
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Neuroblastoma

Neuroblastomas are tumours of neuroblastic origin. Although they may occur anywhere along the sympathetic chain, the vast majority arise from the adrenal gland. They represent the most common extracranial solid childhood malignancy and are the third commonest childhood tumour after leukaemia an...
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Neuroblastoma (staging)

There are two methods of neuroblastoma staging, one that is based on post-operative patients (INSS) and one developed for pre-treatment patients (INRGSS). Staging International Neuroblastoma Staging System (INSS) This staging system is for post-operative patients and mainly for prognosis 1: ...
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Neuroendocrine tumours

Neuroendocrine tumours (NETs) represent a wide spectrum of disease. They consist of a large heterogeneous group of malignancies that are derived from embryonic neural crest tissue found in various organ such as the hypothalamus, pituitary gland, thyroid gland, adrenal medulla, and gastrointestin...
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Nonbacterial thrombotic endocarditis

Nonbacterial thrombotic endocarditis (NBTE), also referred as marantic endocarditis, refers to fibrin and platelets aggregations on previously undamaged heart valves, in patients without bacteraemia. The condition is seen in patients with advanced stage malignancies and is related to episodes of...
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Ocular pathology

Ocular pathology covers a wide range of conditions and therefore represents the cause of a wide range of symptoms, signs and radiographic features. Ocular metastases account for over 80% of all ocular pathology. With regard to the remainder of ocular lesions, the primary differentiating factor ...
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Oesophageal cancer (staging)

Oesophageal cancer staging can depend slightly on whether the tumour is squamous cell or adenocarcinoma subtype. Due to the lack of a serosal layer, oesophageal cancer often tends to have mediastinal spread at the time of diagnosis. Staging TNM staging T staging Tx: primary tumour cannot be...
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Oesophageal cancer (summary)

This is a basic article for medical students and other non-radiologists Oesophageal cancer is a relatively uncommon tumour that occurs within the oesophagus of affected individuals. Patients present with symptoms of increasing dysphagia that progress from solid foods to liquids. Reference arti...
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Oesophageal carcinoma

Oesophageal carcinoma is relatively uncommon. It tends to present with increasing dysphagia, initially to solids and progressing to liquids as the tumour increases in size, obstructing the lumen of the oesophagus. Epidemiology Oesophageal cancer is responsible for <1% of all cancers and 4-10% ...
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Oesophageal mass (mnemonic)

A mnemonic to remember the causes of an oesophageal mass is: CALL the MVP Mnemonic C: carcinoma A: adenoma L: lymphoma L: leiomyoma M: metastasis V: varices P: papilloma/polyp
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Oligometastases

Oligometastases refers to distant disease that is limited in number and distribution, Niibe et al. defined this as ≤5 metastatic/recurrent lesions with control of the primary lesion 1,2. These metastases can be treated with local measures (surgery, radiation therapy, etc.) with the aim of increa...
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Omental cake

Omental cake refers to infiltration of the omental fat by material of soft-tissue density. The appearances refer to the contiguous omental mass simulating the top of a cake. Masses on the peritoneal surfaces and malignant ascites may also be present.  Pathology The most common cause is metasta...
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Ommaya reservoir

Ommaya reservoir, also known as Ommaya shunt, is a device consisting of an intraventricular catheter connected to a reservoir (port) implanted beneath the scalp. It is used for intrathecal administration of medication such as chemotherapy (mainly in the treatment of meningeal lymphomas, but also...
Article

Optic nerve enlargement

Enlargement of the optic nerves is uncommon and has a surprisingly broad differential: optic nerve glioma optic nerve meningioma orbital pseudotumour optic neuritis sarcoidosis leukemia orbital lymphoma metastases perioptic haemorrhage Erdheim-Chester disease juvenile xanthogranuloma ...
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Optic nerve sheath meningioma

Optic nerve meningiomas are benign tumours arising from the arachnoid cap cells of the optic nerve sheath, and represent ~20% of all orbital meningiomas, the majority of which are direct extensions from intracranial meningiomas.  These tumours typically appear as masses within the optic nerve, ...
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Orbital metastasis

Orbital metastases are relatively uncommon, but some primary tumours do have a predilection to metastasise to the orbit. This article concerns itself with extraocular metastases, rather than intraocular tumours or direct extension of tumours from neighbouring regions. For a discussion of intrao...
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Orbital pathology

Orbital pathology covers a variety of diverse diseases that affect the orbit. The complicating factor is that the orbit is composed of a large number of different tissues which each have a plethora of pathologies that can affect them.  Classification For simplification, they can be separated i...
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Osteopoikilosis

Osteopoikilosis is a sclerosing bony dysplasia characterised by multiple benign enostoses. It is a rare inherited benign condition incidentally found on skeletal x-rays. Its importance is predominantly in correct diagnosis so that it is not mistaken for pathology. Epidemiology The bone islands...
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Ovarian cancer (staging)

The most commonly adopted ovarian cancer staging system is the FIGO staging system. The most recent staging system is from 2014 1: CT is considered the best imaging modality for staging ovarian cancer. 4. stage I:  tumour limited to the ovaries stage Ia:  ​tumour limited to one ovary capsul...
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Ovarian embryonal carcinoma

Ovarian embryonal carcinomas are rare and malignant germ cell tumours of the ovary. Epidemiology It is found predominantly in children and adolescents (average age 14 years). Clinical presentation Precocious puberty or menstrual irregularity occurs in 60% 2. The tumor can secrete beta-hCG an...
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Ovarian Sertoli-Leydig cell tumour

Ovarian Sertoli-Leydig cell tumours (SLCT), also known as an ovarian androblastomas, are a subtype of ovarian sex cord-stromal tumour. Epidemiology They are rare and only account for ~0.5% of all ovarian tumours. While they can present at any age, they typically present <30 years old, with a m...
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Ovarian thecoma

Ovarian thecomas are benign ovarian tumours of sex cord / stromal (mesenchymal) origin. They are thought to account for approximately 0.5-1% of all ovarian tumours. As ovarian thecomas secrete oestrogen, they are described as functional ovarian tumours. Epidemiology They typically present in o...
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Ovarian transposition

Ovarian transposition is a surgical procedure in which the ovaries are displaced from the pelvis before pelvic radiation therapy in order to protect them from radiation injury. It is performed in premenopausal women with a variety of pelvic malignancies (e.g cervical cancer, rectal cancer, and ...
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P16

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 in gynaecological malignancy and is a surrogate marker for HSILs (high-grade squamous intraepithelial lesions). It has also been employed to ...
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Paediatric renal tumours and masses

Paediatric renal tumours and masses are another group of diseases (just like cystic renal diseases in both the adult and child) that are bewildering in their number, nomenclature and overlapping findings. Commoner lesions Wilms tumour: common in older children 1-8 years old nephroblastomatosi...
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Paget disease (breast)

Paget disease of the breast, which is also known as Paget disease of the nipple, has traditionally been described as a form of breast malignancy characterised by infiltration of the nipple epidermis by malignant cells. Although most cases have underlying focus or foci of in situ or invasive carc...
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Pancreatic calcifications

Pancreatic calcifications can arise from many aetiologies. Punctate intraductal calcifications chronic pancreatitis alcoholic pancreatitis (20-40%) 2  intraductal, numerous, small, irregular preponderant cause of diffuse pancreatic intraductal calcification gallstone pancreatitis (2%) 2 ​...
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Pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma makes up the vast majority (~90%) of all pancreatic neoplasms and remains a disease with a very poor prognosis and high morbidity. On imaging, it usually presents as a hypodense mass on CT that is poorly marginated, which may encase vessels and the common biliar...
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Pancreatic ductal adenocarcinoma (staging)

Staging of pancreatic ductal adenocarcinoma is traditionally done according to American Joint Committee on Cancer (AJCC) / Union for International Cancer Control (IUCC) TNM system.  In 2017 new edition (8th edition) AJCC published with some major changes; now exocrine and endocrine tumours of th...
Article

Pancreatic lymphoma

Pancreatic lymphoma is most commonly a B-cell sub-type of non-Hodgkin lymphoma. Epidemiology Pancreatic lymphoma is typically seen in middle-aged patients with a mean age of around 55 years old and is more common in immunocompromised patients. Clinical presentation Symptoms are often non-spe...
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Pancreatic mesenchymal neoplasms

Pancreatic mesenchymal neoplasms (or pancreatic nonepithelial neoplasms) are a group of rare pancreatic neoplasms that arise from the structural elements of the pancreas (nerves, fat, lymph), rather than from the exocrine or endocrine cells of the pancreas. Neoplasms from exocrine and endocrine ...
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Pancreatic metastases

Pancreatic metastases are uncommon and are only found in a minority (3-12%) of patients with widespread metastatic disease at autopsy. They account for only 2-5% of all pancreatic malignancies. Epidemiology Demographics will match those of the primary tumour, but in general will be in elderly ...
Article

Pancreatic neoplasms

There are numerous primary pancreatic neoplasms, in part due to the mixed endocrine and exocrine components. Classification Classification based on function exocrine: ~99% of all primary pancreatic neoplasms pancreatic ductal adenocarcinoma ~90-95% cystic neoplasm intraductal papillary muc...
Article

Pancreatoblastoma

Pancreatoblastomas are rare paediatric tumours of the pancreas. However, they are the most common pancreatic neoplasm of childhood and are often associated with a raised alpha-fetoprotein. Epidemiology There is slight male predilection. Usually occurs in the first decade of life with a mean ag...
Article

Papillary carcinoma of the breast

Papillary carcinoma of the breast is a rare ductal breast malignancy. Epidemiology They are thought to account for 1-2% of breast carcinomas 2. They typically present in postmenopausal patients with the mean age at being ~63-67 years. Clinical presentation A papillary carcinoma may manifest ...
Article

Papillary cystadenoma of the epididymis

Papillary cystadenomas of the epididymis are the second most common benign tumours of the epididymis after adenomatoid tumours and are common in patients with von Hippel-Lindau disease (vHL). Clinical presentation Papillary cystadenomas are usually asymptomatic. Epidemiology They are more co...
Article

Papillary meningioma

Papillary meningiomas (PM) are a rare subtype of malignant (WHO grade III) meningiomas that tends to occur in young patients and are characterised by an aggressive growth pattern illustrated by atypical imaging features such as brain and bone invasion. These tumours have a strong tendency of rec...
Article

Paraganglioma

Paragangliomas, sometimes called glomus tumours, are rare neuroendocrine tumours arising from paraganglia.  Terminology Paraganglia are clusters of neuroendocrine cells dispersed throughout the body and closely related to the autonomic nervous system, with either parasympathetic or sympathetic...
Article

Paraneoplastic syndromes

Paraneoplastic syndromes occur secondary to the indirect effects of a malignancy and occur remotely to the primary malignancy. Symptoms are mediated by cytokines, hormones or immune cross-reactivity. These syndromes can cause a diverse range of symptoms and can affect multiple systems. Epidemio...
Article

Parotid enlargement

Parotid enlargement (also known as parotidomegaly) has a wide differential given the significant breadth of pathology that can affect the parotid gland. These can be separated by the standard surgical sieve approach into infective, inflammatory, immune, neoplastic, infiltrative, and congenital c...
Article

Patellar tumours

Patellar tumours are extremely rare. They can be either benign or malignant primary bone tumours, or metastases.  Epidemiology Patellar tumours represent just 0.1% of all primary bone tumours 1.  Clinical presentation Patients may present with anterior knee pain and/or a palpable mass 1,3. ...
Article

Pedunculated intratracheal mass

A pedunculated intratracheal mass has a variety of differential diagnoses: benign tumour, e.g. hamartoma, chrondroma, lipoma haemangioma inspissated mucus metastasis to tracheal mucosa, e.g. renal cell carcinoma, melanoma polyp, e.g. inflammatory, antrochoanal papilloma post-intubation tr...
Article

Pelvic masses in females

Pelvic masses in females carry a broad differential diagnosis: benign adnexal cyst: 34% leiomyoma: 14% pelvic malignancy: 14% dermoid: 13% endometriosis: 10% pelvic inflammatory disease: 8% tubo-ovarian abscess hydrosalpinx pregnancy Extra-gynaecological masses, e.g. colorectal carcino...
Article

PERCIST

Positron Emission Tomography Response Criteria in Solid Tumors (PERCIST) make use of positron emission tomography (PET) to provide functional information to help determine tumour viability. The criteria consist of four categories: complete metabolic response (CMR), partial metabolic response (P...
Article

Pericardial mesothelioma

Pericardial mesothelioma refers to a mesothelioma arising primarily from the pericardium.  Epidemiology They are rare and are only thought to account for ~0.7% of all malignant mesotheliomas. There is male to female predominance of approximately 3:1. Clinical presentation The presentation of...
Article

Perineural spread of tumour

Perineural spread of tumour is a form of local invasion in which primary tumours cells spread along the tissues of the nerve sheath.  It is a well-recognised phenomenon in head and neck cancers. Terminology An important distinction has to be made between perineural invasion (PNI) and perineura...
Article

Periosteal osteosarcoma

Periosteal osteosarcoma is a form of surface osteosarcoma.  Epidemiology It is the second most common type of juxtacortical or surface osteosarcoma after parosteal osteosarcoma and accounts for 1.5% of all osteosarcoma cases. It affects a slightly older age group (10-20 years) cf. conventional...
Article

Peripheral pulmonary carcinoid tumour

Peripheral pulmonary carcinoid tumour refer to a subtype of pulmonary carcinoid tumours that arise within the periphery of the lung. They are considered less common than the more centrally-located bronchial carcinoid tumours.  Clinical presentation Many patients tend to be asymptomatic  2. Pre...
Article

Peritoneal calcification

Peritoneal calcification is seen in a limited number of conditions that result in calcification of peritoneal structures. Therefore, the differential diagnosis is small: psammoma bodies in malignancy (most frequently cystadenocarcinoma of the ovary): fine sand-like calcification pseudomyxoma p...

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