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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.

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Thymic tumor (staging)

The thymic tumor staging using the TNM staging system only applies to the epithelial types including thymoma, thymic carcinoma, and neuroendocrine tumors of the thymus. It does not apply to thymic sarcoma, primary thymic lymphoma or other rare tumors. This staging system is based upon recommend...

PSMA theranostics

PSMA theranostics is an emerging nuclear medicine approach in the management of prostate cancer that combines the use of prostate-specific membrane antigen (PSMA)-targeted imaging and therapy 1. PSMA-targeted imaging can be used to identify and locate prostate cancer cells, while PSMA radioligan...

Akeret staging of neuroepithelial tumors

The Akeret or anatomical staging of neuroepithelial tumors adheres loosely to the general scheme underlying AJCC TNM staging. Like other cancer staging systems it assists in estimating the individual prognosis, in tailoring patient-specific therapy and surveillance, and in improving the comparab...

Gliomatosis peritonei

Gliomatosis peritonei is very rare and is characterized by the implantation of benign mature glial tissue in the peritoneum, omentum, and/or lymph nodes. It is usually associated with ovarian teratoma, although has rarely been seen with other teratomas 1-4. Rarely gliomatosis peritonei has also...

Solitary bone tumor imaging reporting and data system (BTI-RADS)

Solitary bone tumor imaging reporting and data system (BTI-RADS) is a reporting and communication tool designed to stratify benign and malignant bone lesions and to communicate them in a systematic and standardized way 1,2. History and etymology The solitary bone tumor imaging reporting and da...

Numb chin syndrome

Numb chin syndrome describes a sensory neuropathy occurring in the distribution of either the mental nerve or inferior alveolar nerve. While numb chin syndrome has a multitude of causes, it is considered an ominous entity due to its strong association with heralding advanced malignancy 1. Clini...

Osseous Tumor Reporting and Data System (OT-RADS)

Osseous Tumor Reporting and Data System (OT-RADS) is a reporting and communication tool designed to reliably identify benign and malignant bone tumors and to communicate them in a standardized way, using BI-RADS as an example 1-3. History and etymology The Osseous Tumor Reporting and Data Syst...

CNS tumor with BCOR internal tandem duplication

CNS tumor with BCOR internal tandem duplication (BCOR-ITD) is a rare and relatively new brain tumor type that has been added to the WHO classification of CNS tumors 5th edition as part of the embryonal family of tumors. Originally identified through molecular analysis of tumors classified as pri...

Garcin syndrome

Garcin syndrome, also known as hemibasal syndrome or Guillain-Alajouanine-Garcin syndrome, is characterized by progressive ipsilateral cranial neuropathies of at least seven cranial nerves, with no evidence of raised intracranial pressure, long-tract signs, or cerebellar signs, classically attri...

Peripheral intermediate and high-grade chondrosarcoma

Peripheral chondrosarcomas grade 2 and 3 are malignant intermediate and high-grade chondrogenic neoplasms originating from the bony surface in the chondral cap of pre-existing osteochondromas as a result of malignant transformation, thus the name secondary peripheral chondrosarcoma 1,2. Secondar...

Peripheral atypical cartilaginous tumor/ low-grade peripheral chondrosarcoma

Peripheral atypical cartilaginous tumors/chondrosarcomas grade 1 (ACT/CS1) or low-grade peripheral chondrosarcomas are locally aggressive chondral neoplasms that grow within the cartilaginous cap of pre-existing osteochondromas as a result of malignant transformation. Thus these peripheral chond...

Central intermediate and high-grade chondrosarcoma

Central chondrosarcomas grade 2 and 3 (CS2/CS3) are malignant intermediate- and high-grade conventional chondrosarcomas that arise intramedullary 1-3. Epidemiology Similar to low-grade chondrosarcoma, the incidence of central intermediate and high-grade chondrosarcomas has also risen compared ...

Central atypical cartilaginous tumor/ low-grade chondrosarcoma

Central atypical cartilaginous tumors/chondrosarcomas grade 1 (ACT/CS1) or low-grade central chondrosarcomas are locally aggressive chondral neoplasms that arise centrally within bone from the medullar cavity. They constitute the most common form of conventional chondrosarcoma. Terminology The...

Jewett-Strong-Marshall tumor staging system

Jewett-Strong-Marshall tumor staging system for bladder cancer is of historic interest only and has been superseded by the TNM staging system. stage 0: epithelial stage A: submucosal invasion but no involvement of muscle i.e. lamina propria stage B: bladder wall or muscle invasion B1: superf...

Gastric neuroendocrine tumor

Gastric neuroendocrine tumors (GNETs), previously known as gastric carcinoids, are rare primary neoplasms that arise from enterochromaffin-like cells of the gastric mucosa. Epidemiology GNETs account for less than 2% of all gastric neoplasms and up to 10% of all gastrointestinal neuroendocrine...

Succinate dehydrogenase (SDHx) gene mutation

Succinate dehydrogenase gene (SDHx) germline mutations increase the risk of sympathetic paragangliomas, head and neck paragangliomas, pheochromocytomas, renal cell carcinoma (RCC), and gastric gastrointestinal stromal tumors (GIST) 1,2,6,7. Pathology There are four SDH genes - SDHA, SDHB, SDHC...

NTRK-rearranged soft tissue neoplasm

NTRK-rearranged soft tissue neoplasms (emerging), lipofibromatosis-like neural tumors or NTRK-positive tumor-resembling peripheral nerve sheath tumors are a group of rare molecularly defined spindle cell neoplasms excluding infantile fibrosarcoma 1.2. The tumors form a provisional category of un...

Leiomyoma of soft tissue

Soft tissue leiomyomas are benign smooth muscle neoplasms usually found in the somatic deep soft tissues, the retroperitoneum and the abdominal cavity 1. Epidemiology Leiomyomas of the deep somatic tissues are rare soft tissue neoplasms that have been primarily found in middle-aged adults with...

Inflammatory leiomyosarcoma

Inflammatory leiomyosarcomas are malignant tumors with smooth muscle differentiation and a prominent inflammatory infiltrate that were just recently recognized as a distinct entity by the WHO in 2020 1-3. Epidemiology Inflammatory leiomyosarcomas are very rare lesions with most cases seen in a...

Acanthosis nigricans

Acanthosis nigricans is a cutaneous disorder characterized by symmetric hyperpigmented velvety plaques on the neck, axillae, antecubital and popliteal fossae, inframammary, and groin areas. It is associated with acquired lipodystrophy. Pathology The benign form of acanthosis nigricans is assoc...

Anastomosing hemangioma

Anastomosing hemangiomas are benign vascular neoplasms consisting of thin-walled anastomosing vessels. These lesions have been just recently added to the WHO classification of soft tissue tumors in 2020 as a separate entity 1-3 Epidemiology Anastomosing hemangiomas are rare lesions with a wide...

Giant cell fibroblastoma

Giant cell fibroblastomas are locally aggressive mesenchymal neoplasms closely related to dermatofibrosarcoma protuberans. Epidemiology Giant cell fibroblastomas are rare. They are usually but not exclusively found in children within the first decade of life, adult cases are rare. Boys are mor...

EWSR1-SMAD3-positive fibroblastic tumor

EWSR1-SMAD3-positive fibroblastic tumors are benign mesenchymal neoplasms with different morphologies and a provisional name that have been just recently characterized (c.2018) 1-4 and added to the WHO classification of soft tissue tumors in 2020 2,3. Epidemiology EWSR1-SMAD3-positive fibrobla...

Superficial CD34-positive fibroblastic tumor

Superficial CD34-positive fibroblastic tumors (SCPFT) or PRDM10-rearranged soft tissue tumors are rare low-grade mesenchymal neoplasms of the dermis and subcutis 1-3 that have been just recently added to the WHO classification of soft tissue tumors in 2020 2,3. Epidemiology Superficial CD34-po...

Retiform hemangioendothelioma

Retiform hemangioendotheliomas or hobnail hemangioendotheliomas are intermediate locally aggressive and rarely metastasizing vascular neoplasms with a distinctive hobnail endothelial cell morphology. Epidemiology Retiform hemangioendotheliomas are rare with <100 cases reported in the literatur...

Adenosquamous carcinoma of the pancreas

Adenosquamous carcinoma of the pancreas is a rare, highly aggressive malignancy, clinically indistinguishable from the more common pancreatic ductal adenocarcinoma. Their defining pathological and imaging characteristics are the frequent presence of central necrosis and vascular invasion. Termi...

Residual tumor classification

Residual tumor classification, also known as R classification, defines how complete the resection of a malignancy has been at surgery. It has an important prognostic implication. Classification R0: no residual tumor R1: microscopic residual tumor R2: macroscopic residual tumor An R0 resecti...

Normal imaging examples

This article lists examples of normal imaging divided by body region and system. brain head and neck spine chest breast gastrointestinal genitourinary hepatobiliary upper limb lower limb pediatrics

Tenosynovial giant cell tumor

Tenosynovial giant cell tumors (GCT), also known as tenosynovial tumors of tendon sheath, are a group of so-called fibrohistiocytic tumors, which are usually benign, most often arise from the synovium of joints, bursae or tendon sheaths, and show synovial differentiation 1-5. Despite identical h...

Giant cell tumor (disambiguation)

There are a few types of giant cell tumors that may be morphologically similar but are genetically unrelated 1-3: giant cell tumor of bone giant cell tumor of soft tissue tenosynovial giant cell tumor localized tenosynovial giant cell tumor diffuse tenosynovial giant cell tumor

Sinonasal carcinoma

Sinonasal carcinomas are a broad group of sinonasal malignant tumors that are of epithelial cell origin/lineage. Pathology Sinonasal carcinomas can be classified into various histological and etiological subgroups: sinonasal squamous cell carcinoma: considered the most common histological sub...

Apical chest mass

Apical chest masses are often important and may be missed, especially when examined with a plain chest radiograph. It is always recommended to perform a targeted assessment of the apices of the lungs during a chest x-ray; they are one of the classic review areas. Pathology Etiology Commonly a...

Effect of insulin on FDG-PET

Insulin administration has an effect on FDG-PET by affecting the biodistribution of the radiotracer, F-18-fluorodeoxyglucose (FDG), the FDG organic ligand being an analog of glucose, posing a challenge for imaging those with diabetes mellitus. FDG-PET-CT is a hybrid imaging modality commonly us...

Soft tissue mass

Soft tissue masses or lesions are a common medical condition seen by primary care physicians, family physicians, surgeons and orthopedists. They include all soft tissue outgrowths benign and malignant 1-3. Epidemiology Soft tissue masses are very common, with benign lesions being much more fre...

Osteolytic bone lesion

Osteolytic lesions, lytic or lucent bone lesions are descriptive terms for lesions that replace normal bone or with a vast proportion showing a lower density or attenuation than the normal cancellous bone. This comprises lesions with fatty liquid and solid soft tissue components. Pathology Luc...

RNA

RNA (ribonucleic acid) is one of the two major nucleic acids in biological cells, the other being DNA; unlike DNA, RNA is single-stranded. The composition of the nucleotides and nucleosides is also partly different due to variations in the monosaccharide and base constituents: D-ribose sugar rep...

Mixed density bone lesion

The term mixed density bone lesion is used to describe lesions with a combination of osteolytic and osteosclerotic components within or adjacent to cancellous bone. The amount of osteolytic and osteoblastic areas within the lesion remains more or less subjective 1. Differential diagnosis Simil...

Three-territory sign (brain)

The three-territory sign is a radiological sign described in ischemic stroke and is highly specific to hypercoagulability due to malignancy (Trousseau syndrome) being the etiology. However, this sign is not pathognomonic, and may be seen with cardioembolic stroke (e.g. due to atrial fibrillation...

Low T1 bone lesion

Low T1 bone lesions or T1 hypointense bone lesions are radiological terms to categorize bone lesions according to their visually perceived low signal on T1 weighted images. Apart from the usual description of a bone lesion seen on MRI they are used to categorize incidentally found solitary bone ...

High T1 bone lesion

High T1 bone lesions or T1 hyperintense bone lesions are radiological terms to categorize bone lesions with a high signal on T1 weighted images. Apart from the usual description of a bone lesion seen on MRI the terms can be used to categorize incidentally found solitary bone lesions in the Bone ...

Chemical ablation

Chemical ablation is a technique in which chemical ablative substances are used to cause cell death in neoplastic tissue. It is used as a standalone procedure or in combination with other techniques like TACE and radiofrequency ablation. Agents absolute ethanol (most commonly used) acetic aci...

Renal large cell neuroendocrine carcinoma

Renal large cell neuroendocrine carcinomas are an extremely rare renal tumor, with only six cases reported in the literature (c. 2022) 1. Epidemiology Renal large cell neuroendocrine carcinoma represents <1% of the total reported cases of primary renal cancers. The most affected population i...

Complications of radiation therapy

Radiation therapy has the potential to cause complications in many organ systems, many of which, especially in the thorax, are important for radiologists to be aware of. acute radiation syndrome complications of cranial radiation therapy radiation-induced cerebral vasculopathy radiation-ind...

Salivary duct carcinoma

Salivary duct carcinomas are a subtype of primary salivary gland tumor. Salivary duct carcinomas show high rates of metastasis and recurrence. Epidemiology Salivary duct carcinomas represent 5-10% of salivary gland malignancies and can arise de novo or out of a pleomorphic adenoma 1,2. They t...

Bone Reporting and Data System (Bone-RADS)

The Bone Reporting and Data System (Bone-RADS) is an algorithm developed and proposed by the Practice Guidelines and Technical Standards Committee of the Society of Skeletal Radiology for the diagnostic workup of incidentally encountered solitary bone lesions in adults on MRI and/or CT 1. It has...

CSF alpha-fetoprotein

Alpha-fetoprotein (AFP) in the cerebrospinal spinal fluid (CSF) has been reported as a tumor marker for some intracranial tumors with yolk sac elements, and teratoma 1. Interpretation Elevation intracranial yolk sac tumor intracranial embryonal carcinoma congenital CNS tumors with yolk sac ...

Sea anemone sign

The sea anemone sign is a unique (but not wholly exclusive) appearance seen in ovarian serous surface papillary borderline tumors (SSPBT). It refers to its surface stroma frequently branches into exophytic papillary stalks, macroscopically 1. Radiographic features On cross-sectional imaging, p...

Diffuse hemispheric glioma H3 G34 mutant

Diffuse hemispheric gliomas, H3 G34 mutant are rare and high grade infiltrating tumors typically presenting in adolescents and young adults. Terminology Diffuse hemispheric gliomas H3 G34 mutant have been recently included in the 5th Edition (2021) of the WHO brain tumor classification 1 among...

Tumor pseudoprogression (lung cancer)

Radiologic tumor pseudoprogression on imaging denotes an imaging appearance of tumor response where the tumor first exhibits findings suggestive of progression (i.e. growth, new lesions). However, during sustained therapy, response is eventually demonstrated 1. Epidemiology With the advent of ...

Intraparotid nodal metastases

Intraparotid nodal metastases refer to metastatic involvement of intraparotid lymph nodes from either a primary parotid tumor or an extraparotid tumor in the head and neck (e.g. nasopharyngeal carcinoma). Pathology Location There may be a predilection towards the superficial lobe or tail regi...

IOTA-ADNEX model

The ADNEX (Assessment of Different NEoplasias in the adneXa) model is a risk model developed by the IOTA (International Ovarian Tumor Analysis) group to differentiate benign and malignant neoplasms of the ovary and, among them, four different subgroups (borderline, stage I cancer, stage II-IV ca...

Peripheral T cell lymphoma

Peripheral T cell lymphoma is an uncommon, heterogeneous group of lymphoma. It can account for around 5-15% of non-Hodgkin lymphoma (NHL). Terminology The word "peripheral" does not mean involvement in the extremities but refers to tumor cells that arise from lymphoid tissue outside of the bon...

WHO classification of skin tumors

The World Health Organizatiοn classification of skin tumors is the most widely used pathologic classification system for skin tumors. The most recent edition is the 4th, which was published in 2018 1. The radiologically relevant and common entities are reflected below. Classification 1. Kera...

Submandibular gland enlargement

Submandibular gland enlargement refers to an increase in the volume of the submandibular gland, exceeding "normal" values of 7.4 ± 1.8 mL 1. Pathology Causes Obstruction sialolithiasis submandibular duct stenosis (e.g. tumor, granulomatous disease) Infection acute sialadenitis: following ...

Salt and pepper sign (paraganglioma)

The salt and pepper sign is used to describe a typical MRI appearance of some highly vascular tumors which contain foci of hemorrhage, typically a paraganglioma 1-3. The appearance is on T1-weighted sequences, and is made up of: punctate regions of hyperintensity = salt small flow voids = pepp...

Polymorphous low grade neuroepithelial tumor of the young

Polymorphous low-grade neuroepithelial tumor of the young (PLNTY) is an epileptogenic tumor of children and young adults. Terminology First described in 2016 1, polymorphous low-grade neuroepithelial tumor of the young has been recently included in the new family of "pediatric-type" low-grade ...

Cachexia

Cachexia is a syndrome of metabolic dysfunction secondary to an underlying disease in which there is depleted skeletal muscle (sarcopenia) which may or may not be accompanied by an absolute loss of body fat. Terminology Cancer cachexia is specifically used to refer to the cachexia associated ...

Fibrosing inflammatory pseudotumor

Fibrosing inflammatory pseudotumors are an inflammatory process with histology showing a polymorphous infiltrate with plasma cells, lymphocytes and eosinophils as well as a significant reactive fibrovascular component. Pathology Location They can occur at various sites of the body including: ...

Night sweats

Night sweats, also known as sleep hyperhidrosis, are a common clinical complaint and may herald malignancy, especially lymphoma, or infections. Patients typically report waking up in the night with sweating so severe that their clothes and bed sheets are soaked through ("drenching sweats") and n...

Blast crisis

A blast crisis or lymphoid blast crisis refers to the transition of chronic or accelerated phase chronic myeloid leukemia to acute leukemia. It is usually characterized by ≥30% blasts in the bone marrow or peripheral blood or development of extramedullary disease outside of the spleen Among p...

Rectal MRI (an approach)

Rectal MRI is a key imaging investigation in the diagnosis, staging and follow up of rectal cancer. An increase in the utility of rectal MRI as been driven by the recognition of the mesorectum as a distinct anatomic compartment containing and limiting the margins of the rectum, and forming a sur...

Pembrolizumab induced pneumonitis

Pembrolizumab induced pneumonitis is a form of drug-induced lung disease occurring as a result of a response to the use of the programmed cell death protein 1 (PD1) inhibitor pembrolizumab. It may have variable pattern 2. Pembrolizumab is also reported to have a high risk of inducing lung inju...

Clear cell papillary renal cell carcinoma

Clear cell papillary renal cell carcinoma is a subtype renal cell carcinoma. Epidemiology Generally uncommon but thought to be the fourth most common histologic type of renal cell carcinoma at the time of new classification (c. 2016) 1. Pathology This subtype is characterized by low-grade, c...

Fluid-fluid levels in liver lesions

Fluid-fluid levels in liver lesions are a rare appearance of both benign and malignant conditions. Differential diagnosis benign complicated hepatic cyst 2 hepatic abscess 2 chronic hepatic hematoma 3 biliary cystadenoma 3 hepatic hemangioma (very rare) 2 malignant cystic/necrotic hepat...

Carcinoma of the Littré glands

Carcinoma of the Littré glands is rare. The Littré (urethral) glands of the penis may be the origin of cancers of the penis, usually adenocarcinomas 1. Epidemiology There are only a few scattered case reports of true Littré gland malignancy, although it is probably under-reported due to the fa...

Hepatic small vessel neoplasm

Hepatic small vessel neoplasms (HSVN) are low-grade vascular lesions of uncertain malignant potential. Terminology Although also referred to as hepatic small vessel hemangiomas 3, this term may wrongly mislead HSVN to represent a subtype of hepatic hemangiomas and, therefore, will be avoided ...

Solitary fibrous tumor of the orbit

The solitary fibrous tumor of the orbit is a rare spindle-cell neoplasm originating from mesenchymal fibroblast-like cells histologically identical to solitary fibrous tumors found elsewhere Epidemiology Solitary fibrous tumors occur in a wide age range reported from 9 to 76 years without a co...

Immunosuppression

Immunosuppression is the impairment of the body's immune system which can alter the ability of the body's defense mechanisms to prevent diseases, particularly certain infections, including opportunistic infections, and cancers. Terminology Patients with immunosuppression are said to be immuno...

Oncocytic sinonasal papilloma

Oncocytic sinonasal papillomas (OSP) or cylindrical cell papillomas are a rare form of Schneiderian papillomas and benign epithelial sinonasal tumors arising from the Schneiderian epithelium of the nasal cavity and paranasal sinuses. Epidemiology Oncocytic sinonasal papillomas are the least fr...

Primary intraosseous carcinoma

Primary intraosseous carcinomas NOS (PIOC) are malignant epithelial odontogenic neoplasms of the jawbones with no clear benign analog. Epidemiology Primary intraosseous carcinomas are rare tumors 1-4. They occur in a wide age range with the mean in the sixth decade of life. Men are more freque...

Ameloblastic carcinoma

Ameloblastic carcinomas or malignant ameloblastoma are malignant epithelial odontogenic neoplasms with histologic features ameloblastoma. Epidemiology Ameloblastic carcinomas are rare tumors approximately accounting for 1% of jaw tumors 1,2. They have been found in a wide age range and are mor...

Alcian blue stain

Alcian blue stain is a histological stain utilized for the identification of extracellular matrix proteoglycans, like glycosaminoglycans and hyaluronic acid 1, commonly in connective tissue and epithelial malignant neoplasms 2, and also Barrett esophagus, where it can highlight mucosal intestina...

Giemsa stain

Giemsa stain is a commonly used histological stain that colors the cytoplasm blue to pink (depending on its acidity) and the nucleus blue to black 1. It serves as the diagnostic gold standard of histopathological staining of blood samples from patients with plasmodium-borne malaria, and as the b...

Tobacco use

Tobacco use, most commonly by smoking cigarettes, is a drug habit of many throughout the world. It is a significant risk factor for many malignancies, and respiratory and cardiovascular diseases and is a major cause of premature mortality throughout the world. Epidemiology The World Health Org...

Dentinogenic ghost cell tumor

Dentinogenic ghost cell tumors (DGCT) are benign mixed epithelial and mesenchymal odontogenic tumors with locally aggressive behavior. Terminology It is also known as the 'solid' or 'neoplastic form of calcifying odontogenic cyst’, since the 4th WHO classification of head and neck tumors in 20...

Squamous cell carcinoma of the penis

Squamous cell carcinoma (SCC) of the penis is an uncommon condition that often presents at an advanced stage. Imaging is more often used for staging than for the initial diagnosis. It is the commonest histological subtype of penile cancer. Epidemiology Penile cancer is a relatively infrequent ...

Hairy cell leukemia

Hairy cell leukemia is a rare and indolent form of small mature B-cell leukaemias. Epidemiology Its annual incidence is estimated at around 0.3 cases per 100 000, and the disease comprises 2-3% of all leukaemias. There is a recognized male predilection of around 4:1 with a median age of around...

Mixed germ cell tumor of the mediastinum

Mixed germ cell tumors of the mediastinum or mediastinal mixed germ cell tumors are malignant non-seminomatous germ cell tumors of the mediastinum consisting of more than one type of germ cell tumor. Terminology The term ‘malignant teratoma’ is not recommended. Epidemiology Mixed germ cell t...

Aerogenous metastasis

Aerogenous metastases are a rare form of metastases that can occur in the lung due to aerogenous spread along the airways. Pathology It is related to but not considered identical to the term spread through air spaces (STAS) 4. Aerogenous metastases are usually from primary lung cancer dissemi...

Mediastinal choriocarcinoma

Mediastinal choriocarcinomas or choriocarcinomas of the mediastinum are malignant non-seminomatous germ cell tumors of the mediastinum consisting of trophoblastic cells. Epidemiology Pure choriocarcinomas are rare and account for up to 3% of primary mediastinal germ cell tumors 1. They usually...

Mediastinal embryonal carcinoma

Mediastinal embryonal carcinomas or embryonal carcinomas of the mediastinum are malignant non-seminomatous germ cell tumors with embryonal type cells primarily growing in the mediastinum. Epidemiology Mediastinal embryonal carcinomas are very rare mediastinal tumors accounting for up to 8% of ...

Mediastinal yolk sac tumor

Mediastinal yolk sac tumors or yolk sac tumors of the mediastinum are malignant non-seminomatous germ cell tumors primarily growing in the mediastinum. Terminology The term ‘endodermal sinus tumor’ is not recommended. Epidemiology Mediastinal yolk sac tumors are rare mediastinal tumors. In a...

Mediastinal seminoma

Mediastinal seminomas or mediastinal germinomas are primary malignant germ cell tumors of the mediastinum. Epidemiology Mediastinal seminomas are rare mediastinal tumors and account for up to one-third of primary malignant mediastinal germ cell tumors 1. They are almost only found in males ≥10...

Neoplasm

Neoplasms, also known as tumors, are pathological masses, caused by cells abnormally proliferating and/or not appropriately dying. Neoplasms may be either benign or malignant. Malignant neoplasms are synonymous with cancers. Benign neoplasms clear origin (unless very large) slow growth usua...

Cystic tumor of the atrioventricular node

Cystic tumors of the atrioventricular node (CTAVN), also known as endodermal heterotopia, refer to a benign mass lesion of the atrioventricular node that constitutes a developmental endodermal rest. Terminology A term that is no longer recommended for use is ‘mesothelioma of the atrioventricul...

Cardiac undifferentiated pleomorphic sarcoma

Cardiac undifferentiated pleomorphic sarcomas are highly malignant mesenchymal tumors of the heart. Terminology Terms that are no longer recommended for use include ‘intimal sarcoma’, ‘undifferentiated sarcoma’ and ‘undifferentiated spindle cell sarcoma’ 1. Epidemiology Cardiac undifferentia...

Cardiac leiomyosarcoma

Cardiac leiomyosarcomas are malignant smooth muscle tumors of the heart. Epidemiology Cardiac leiomyosarcomas are rare primary malignant tumors of the heart accounting for less than one-fifth of cardiac sarcomas. They have been found in a wide age range from 6 months to 86 years with a mean ag...

Dedifferentiated chordoma

Dedifferentiated chordomas are biphasic malignant tumors composed of notochordal and high-grade sacomatous components. Epidemiology Dedifferentiated chordomas are very rare tumors that might be seen in recurrences or after radiotherapy 1-3. Diagnosis The diagnosis is based on typical imaging...

Poorly differentiated chordoma

Poorly differentiated chordomas are highly aggressive poorly differentiated notochordal tumors with a loss of SMARCB1 expression. Epidemiology Poorly differentiated chordomas are very rare tumors typically seen in children and young adults under the age of 30 years. Females are more frequently...

Bone lymphoma

Lymphoma of the bone may represent lymphoma that has originated within that bone itself i.e. primary, or metastasized there from another organ/tissue, i.e. secondary. Secondary forms of bone lymphoma are much more common than the primary bone form. primary osseous lymphoma secondary osseous ly...

Secondary osteosarcoma

Secondary osteosarcomas are osteosarcomas growing on abnormal bone in the setting of various underlying osseous disorders. Terminology Other acceptable terms include Paget sarcoma, osteosarcoma in Paget disease of bone or radiation-associated osteosarcoma, if applicable. The terms postirradiat...

Small cell osteosarcoma

Small cell osteosarcomas (SCOS) are a rare subtype of osteosarcoma characterized by the production of small round cells. Epidemiology Small cell osteosarcomas account for approximately 1.5% of osteosarcomas. They occur mainly in young adolescents with a mild female predilection but have been f...

Solid variant of aneurysmal bone cyst

The solid variant of the aneurysmal bone cyst (ABC) is a rare non-neoplastic and reactive bone lesion. It differs from the classical type of ABC in certain aspects. Epidemiology The solid variant of ABC has an incidence of ~5% (range 3.4-7.5%) and is found to have slight female predilection (1...

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