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Endometrial hyperplasia

Endometrial hyperplasia is an abnormal proliferation of the endometrial glands and stroma, defined as diffuse smooth thickening >10 mm 13. One of the major concerns is the potential malignant transformation to endometrial carcinoma. Epidemiology Endometrial hyperplasia affects women of all age...

Sister Mary Joseph nodule

A Sister Mary Joseph nodule is a metastatic lesion involving the umbilicus. The most common primary source is an intra-abdominal adenocarcinoma. Epidemiology Umbilical metastases are uncommon, reportedly present in 1-3% of all intra-abdominal and/or pelvic malignancy 7. Clinical presentation ...

Diffusely increased bone marrow FDG uptake

A diffuse homogeneous bone marrow FDG uptake usually reflects hyperplastic bone marrow which can be seen in the following conditions: therapy-related granulocyte colony-stimulating factor (G-CSF) post-chemotherapy erythropoietin pathological process myelodysplastic syndromes beta-thalasse...

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 being 63-67 years. Clinical presentation Papillary carcinomas may manifest clini...

Mucinous carcinoma of the breast

Mucinous carcinoma of the breast, also known as colloid breast carcinoma, is a subtype of invasive ductal carcinoma (IDC). They account for about ~2% (range 1-7% 4) of breast cancers. Epidemiology It tends to occur in older women where a prevalence of as much as 7% is found among women 75 yea...

Tamoxifen-associated endometrial changes

The oncological agent tamoxifen has pro-oestrogenic changes on the endometrium resulting in abnormal growth with an increased prevalence of: endometrial polyps: occurs in ~8-36% of women in treated 8 endometrial hyperplasia: occurs in ~1-20% of women treated ref cystic endometrial atrophy en...

Thorotrast

Thorotrast is a suspension of radioactive thorium dioxide first produced in Germany in 1928, used as a contrast agent until the 1950s. Its principal use was for cerebral angiography: 90% of the estimated 50,000-100,000 patients treated received it for this purpose. Umbrathor was another thorium ...

Renal medullary carcinoma

Renal medullary carcinoma is a very rare and highly aggressive variant of renal cell carcinoma centered in the renal medulla. Epidemiology The overwhelming majority of cases occur in individuals with sickle cell trait (HbAS) and, less commonly, with the hemoglobin SC (HbSC) variant of sickle ...

Thyroid scintigraphy (I-123)

Thyroid scintigraphy (thyroid scan) is a nuclear medicine examination used to evaluate thyroid tissue. Clinical indications functional status of a thyroid nodule thyrotoxicosis: differential diagnosis thyroid cancer whole body scan for distant metastases estimation of local residual thyro...

Lobular carcinoma in situ

Lobular carcinoma in situ (LCIS) represents the next step up from atypical lobular hyperplasia (ALH) along the malignant spectrum of lobular breast carcinoma. Epidemiology Lobular carcinoma in situ occurs predominantly in premenopausal women with a mean age of 45 years old, approximately 10-15...

Ductal carcinoma in situ

Ductal carcinoma in situ (DCIS) refers to a breast carcinoma limited to the ducts with no extension beyond the basement membrane, as a result of which the disease has not infiltrated the parenchyma of the breast and the lymphatics and cannot therefore metastasize. Epidemiology The detection of...

Atypical ductal hyperplasia

Atypical ductal hyperplasia is a histologically borderline lesion that has some, but not all, of the features of ductal carcinoma in situ. Sometimes the distinction between Atypical ductal hyperplasia and ductal carcinoma in situ are simply defined on the number of ducts involved. Pathology A...

Malignant peritoneal mesothelioma

Malignant peritoneal mesothelioma is an uncommon primary tumor of the peritoneal lining. It shares epidemiological and pathological features with - but is less common than - its pleural counterpart, which is described in detail in the general article on mesothelioma. Other abdominal subtypes (al...

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 ...

Follicular lymphoma

Follicular lymphoma is the most common subtype of indolent non-Hodgkin lymphoma (NHL), second most common overall, behind diffuse large B-cell lymphoma 6. Epidemiology Estimated to account for ~45% of all NHL cases 1. Higher rates in North America and Europe 4. Pathology Nodal effacement b...

Pseudomyxoma peritonei

Pseudomyxoma peritonei refers to a syndrome of progressive intraperitoneal accumulation of mucinous ascites related to a mucin-producing neoplasm. It is most commonly caused by a mucinous tumor of the appendix 10. Much less commonly, mucinous tumors of the colon, rectum, stomach, pancreas, and ...

Solitary bone plasmacytoma

Solitary bone plasmacytomas are an uncommon plasma cell tumor which are localized to bone. They may involve any bone, but they have a predisposition for the red marrow-containing axial skeleton: spinal disease is observed in ~50% (range 34-72%) of cases the thoracic vertebrae are most commonly...

Ivory vertebra

The ivory vertebra (also known as ivory vertebra sign) sign refers to the diffuse and homogeneous increase in opacity of a vertebral body that otherwise retains its size and contours and with no change in the opacity and size of adjacent intervertebral discs. Pathology Etiology The cause for ...

Inflammatory carcinoma of the breast

Inflammatory carcinoma of the breast, also referred to as inflammatory breast cancer, is a relatively uncommon but aggressive form of invasive breast carcinoma with a characteristic clinical presentation and unique radiographic appearances. Epidemiology Inflammatory carcinomas account for 1...

Littoral cell angioma of the spleen

Littoral cell angioma of the spleen is a rare, benign primary vascular tumor of the spleen. Epidemiology Littoral cell angiomas may occur at any age and have no gender predilection. Associations Littoral cell angiomas have been diagnosed in association with various malignancies outside the s...

Gallbladder carcinoma

Gallbladder carcinoma is a type of gallbladder cancer and specifically refers to primary epithelial malignancies arising from the gallbladder, in which the great majority (90%) are adenocarcinomas and the remainder are squamous cell carcinomas. They are more prevalent in elderly women and, in mo...

Generalized osteopenia

Generalized osteopenia refers to osteopenia diffusely affecting the bones. Differential diagnosis The differential diagnosis is wide and includes: osteoporosis: decreased osteoid production osteomalacia: undermineralisation of osteoid hyperparathyroidism multiple myeloma diffuse metastase...

Appendiceal mucocele

Appendiceal mucoceles occur when obstruction of the appendiceal lumen causes mucus to accumulate and progressively distend the appendix. The term describes an imaging appearance rather than a pathological entity. The underlying causes lie on a spectrum between benign obstruction with retention c...

Extramedullary hematopoiesis

Extramedullary hematopoiesis is a response to the failure of erythropoiesis in the bone marrow. This article aims to a general approach on the condition, for a dedicated discussion for a particularly involved organ, please refer to the specific articles on: extramedullary hematopoiesis in ...

Breast MRI

Breast MRI is the most sensitive method (>90%) for the detection of breast cancer, its role in diagnosis and management continues to evolve 13. Terminology Dynamic contrast-enhanced (DCE)-MRI provides information about the morphology and function of a lesion with high sensitivity but moderate ...

Bulging duodenal papilla

Bulging duodenal papilla is a conical or cylindrical protuberance at the medial aspect of the descending or horizontal duodenum at the site of the sphincter of Oddi. It is a finding on small bowel follow-though (and endoscopy) and has a relatively long differential. On cross-sectional imaging, ...

Adenoid cystic carcinoma

Adenoid cystic carcinomas are a rare histological subtype of adenocarcinoma. Pathology Adenoid cystic carcinomas are generally considered low grade 4. The tumors have a notable tendency for perineural spread. Location They have a wide distribution and mainly occur in relation to the airways,...

Pulmonary pneumocytoma

Pulmonary pneumocytomas, previously known as pulmonary sclerosing hemangiomas (PSH), are rare benign neoplasms of the lung. Epidemiology Typically presents in middle age (30-50 years of age). There is a recognized female predilection. Clinical presentation Most patients are asymptomatic. S...

Pulmonary lymphoma

Pulmonary lymphoma refers to lung parenchymal involvement with lymphoma. Pathology It can be broadly divided as primary or secondary: primary pulmonary lymphoma: (rare) usually non-Hodgkin lymphoma which is limited to the lung with or without mediastinal lymph node involvement and with no evi...

BALT lymphoma

BALT lymphoma is an abbreviated term for bronchus-associated lymphoid tissue lymphoma. These neoplasms fall under the broader umbrella of mucosa associated lymphoid tissue (MALT) lymphomas. It is sometimes considered a type of primary pulmonary lymphoma. Clinical presentation Up to half of pat...

Carcinosarcoma

Carcinosarcomas are highly malignant biphasic tumors with both carcinomatous (epithelial) and sarcomatous (bone, cartilage, or skeletal muscle) components. Pathology It can arise in many organs: lung 5: pulmonary carcinosarcoma esophagus 1: esophageal carcinosarcoma genitourinary tract 2 ...

Malignant peripheral nerve sheath tumor

Malignant peripheral nerve sheath tumors (MPNSTs) are forms of peripheral nerve sheath tumors occurring either de novo or arising from pre-existing tumors (e.g. neurofibromas, schwannomas etc.). Approximately half of such tumors are seen in individuals with neurofibromatosis type I (NF1), in suc...

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 centers. Epidemiology They occur in older adults (mean age ~60 years), and ther...

Germ cell tumor (classification)

Germ cell tumors are classified into two broad groups: seminoma and non-seminomatous germ cell tumors (NSGCT). The later is then divided further according to histology: seminoma non-seminomatous germ cell tumors (NSGCT) embryonal cell carcinoma choriocarcinoma yolk sac tumor teratoma mixe...

Testicular teratoma

Testicular teratoma, unlike ovarian teratoma, is often aggressive in its biological behavior, and often exists as part of testicular mixed germ cell tumors. Epidemiology Pure testicular teratomas account for only 4-9% of all testicular tumors. A similar number are seen in the context of test...

Prostate sarcoma

Prostate sarcomas are an uncommon and heterogeneous group of tumors arising from mesenchymal cells in and around the prostate (as opposed to the more common prostate adenocarcinoma which derives from the glandular tissue). Pathology In children, the most common tumor type is a prostatic rhabd...

Primary urethral malignant melanoma

Melanoma of the urethra is a very rare tumor of the male urethra and often presents as an invasive prostatic mass. As such it is usually referred to as primary prostatic malignant melanoma.

Tumors of the male urethra

Tumors of the male urethra are uncommon. They can be categorized both on the grounds of histology and location. Histology squamous cell carcinoma of the urethra: 80% urothelial/transitional cell carcinoma of the urethra: 15% (predominantly posterior urethra) adenocarcinoma of the urethra: 5%...

Primary prostatic malignant melanoma

Primary melanoma of the prostate is rare, and usually cannot be diagnosed on imaging alone. In many cases, it is believed that in fact, the tumor represents prostatic involvement by melanoma of the urethra. Epidemiology Primary malignant melanoma of the prostate represents both a tiny fraction...

Urethral diverticulum

Urethral diverticula, or urethroceles, are focal outpouchings of the urethra. They should not be confused with a ureterocele of the distal ureter. Epidemiology Urethral diverticula occur far more frequently in women than in men and are estimated to occur in 1-6% of women, especially those with...

Bone lesions with sequestrum

There are several bony lesions that can involve or produce a sequestrum. They include: Common Brodie abscess: osteomyelitis Less common eosinophilic granuloma certain soft tissue tumors (with bony extension) malignant fibrous histiocytoma lymphoma metastasis (especially from breast ca...

Osteoblastoma

Osteoblastomas are rare bone-forming tumors that may be locally aggressive. Compared to their histological relative, the osteoid osteoma, they are larger (>2 cm) and more frequently affect the axial skeleton 1. Osteoblastoma accounts for the 'O' in the popular mnemonic for lucent bone lesions F...

Extraventricular neurocytoma

Extraventricular neurocytomas, previously known as cerebral neurocytomas, are rare WHO grade 2 primary CNS neoplasms usually arising in the cerebral hemispheres. They are, as the name implies, extraventricular versions of central neurocytomas. Epidemiology These tumors are reported at essenti...

Neurocytoma

Neurocytomas are WHO grade 2 primary CNS neoplasms that derive from neural cells. There are two main types: intraventricular neurocytoma much more common called a central neurocytoma when located centrally within the lateral ventricles extraventricular neurocytoma 1 Both types tend to have ...

Leiomyosarcoma

Leiomyosarcomas are extremely rare malignant neoplasms that originate from smooth muscle cells and may be considered the malignant counterpart of a leiomyoma. They are classified as soft-tissue tumors and account for approximately 8% of malignant soft-tissue tumors 10. Pathology Location Lei...

Juxtacortical chondroma

Juxtacortical chondromas, also known as periosteal chondromas, are rare benign chondral tumors that arise from the periosteum of tubular bones. They are thought to account for ~2% of benign bone tumors. Epidemiology They tend to present around the 2nd to 4th decades. There is a recognized male...

Incidentaloma

An incidentaloma is a radiological neologism to denote a lesion found incidentally and of dubious clinical significance. Although it can refer to any incidental lesion (e.g. pituitary 3, thyroid 4), it is most often used to denote an incidental adrenal lesion, which is commonly an adrenal adenom...

CNS lymphoma

CNS lymphoma refers to the involvement of the central nervous system with lymphoma. It can be broadly divided into primary and secondary, with a number of special types of also recognized. primary lymphomas of the CNS primary diffuse large B-cell lymphoma of the CNS immunodeficiency-associat...

Desmoplastic fibroma

Desmoplastic fibromas are extremely rare bone tumors that do not metastasize but may be locally aggressive. They are considered to be a bony counterpart of soft tissue desmoid tumors and are histologically identical. Epidemiology Desmoplastic fibroma of bone is rare and mostly found in young ...

Myxofibrosarcoma

Myxofibrosarcoma is a malignant soft tissue tumor. It is classified as a type of a fibroblastic/myofibroblastic tumor. Terminology Previously known as a myxoid variant of malignant fibrous histiocytoma 7. Epidemiology Typically presents in older patients (6th decade) 3. There may be male pre...

Adult cervical lymphadenopathy (differential)

Cervical lymphadenopathy in an adult can result from a vast number of conditions. They include: malignancy metastases from head and neck tumors lymphoma other neoplastic lesions Castleman disease Kaposi sarcoma infection bacterial infection viral infection Epstein-Barr virus herpes ...

Technetium-99m agents

Technetium agents based on the technetium-99m (Tc-99m) radioisotope are frequently used agents in medical imaging. A radiopharmaceutical labeled with Tc-99m constitutes a co-ordination complex in which ligands bond to a central atom of Tc-99m by co-ordinate covalent bonds 4 . The radioactive te...

WHO classification of tumors of soft tissue

The World Health Organization (WHO) classification of soft tissue tumors is the most widely used pathology-based classification system for such disorders. The current revision, part of the 5th edition of the WHO classification of soft tissue and bone tumors (volume 3), was published in 2020 and ...

Prostate cancer

Prostate cancer ranks as the most common primary malignant tumor in men and the second most common cause of cancer-related deaths in men. Prostatic adenocarcinoma is by far the most common histological type and is the primary focus of this article. Epidemiology It is primarily a disease of the...

Myeloid sarcoma

Myeloid sarcomas, also called granulocytic sarcomas, chloromas, or extramedullary myeloid tumors, are rare extramedullary masses comprised of myeloid precursor cells. These tumors represent a unique presentation of acute myeloid leukemia (AML), whether in isolation to, preceding, or simultaneous...

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 ...

Carcinoid heart disease

Carcinoid heart disease, also known as Hedinger syndrome, is a known complication of carcinoid tumors, and is particularly prevalent in patients who develop carcinoid syndrome. Epidemiology Cardiac lesions are present in approximately 50% of patients with carcinoid syndrome 1. Clinical presen...

Pharyngeal mucosal space

The pharyngeal (or superficial) mucosal space is a deep compartment of the head and neck, located between the fascia of the pharyngeal constrictor muscles (buccopharyngeal or visceral fascia) and the mucosal surface of the nasopharynx, oropharynx, and hypopharynx. Terminology Not a true anatom...

Parotid gland enlargement

Parotid gland 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 a standard surgical sieve approach into infective, inflammatory, immune, neoplastic, infiltrative, and congenit...

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...

Clavicle tumors

Clavicle tumors may be malignant or benign. Malignant metastases prostate breast cervix ovary urinary bladder carcinoid osteosarcoma osteosarcoma lymphoma primary metastatic Benign osteoma: uncommon, sclerotic, hamartomatous surface lesion enchondroma: rare, geographic, intramedu...

Adrenal cortical carcinoma

Primary adrenal cortical carcinoma (also known as adrenocortical carcinoma) is a highly malignant but rare neoplasm. It may present as a hormonally active or inactive tumor. Epidemiology Although men and women are affected equally, functioning tumors are more common in females, who are also m...

Focal gas collection in right upper quadrant (differential)

Focal gas collection in right upper quadrant on plain radiographs can occur from a number of pathologies. Things to consider are: enterobiliary fistula: common types include cholecystoduodenal fistula and cholecystocolic fistula. It may occur with: gallstone ileus (being most common) 3 perfor...

Breast imaging-reporting and data system (BI-RADS)

BI-RADS (Breast Imaging-Reporting and Data System) is a risk assessment and quality assurance tool developed by American College of Radiology that provides a widely accepted lexicon and reporting schema for imaging of the breast. It applies to mammography, ultrasound, and MRI. This article refle...

Testicular seminoma

Testicular seminomas are a type of germ cell tumor and the most common testicular tumors, accounting for ~45% of all primary testicular tumors. This article concerns itself only with testicular seminomas; however, seminomas can arise outside of the testis; most often within the anterior mediasti...

Adenocarcinoma (urinary bladder)

Adenocarcinoma of the urinary bladder is rare and accounts for only ~1% of all bladder cancers (90% are transitional cell carcinomas). Pathology Metaplasia of urinary bladder induced by chronic irritation or infection can lead to adenocarcinoma. Pathological types of adenocarcinoma of the urin...

Squamous cell carcinoma (urinary bladder)

Squamous cell carcinoma (SCC) of the urinary bladder is rare, nevertheless SCC is the most common type of non-transitional cell carcinoma involving the bladder 2. Most bladder cancers are transitional/urothelial cell carcinomas. SCC is much more common where Schistosomiasis infections are more p...

Transitional cell carcinoma (ureter)

Transitional cell carcinoma (TCC) of the ureter, also called urothelial cell carcinoma (UCC) of the ureter, are uncommon compared to similar tumors elsewhere along the urinary tract but are nonetheless the most common primary tumor of the ureter. This article concerns itself with transitional c...

Transitional cell carcinoma (renal pelvis)

Transitional cell carcinoma (TCC) of the renal pelvis, also called urothelial cell carcinoma (UCC) of the renal pelvis, is uncommon compared to renal cell carcinoma and can be challenging to identify on routine imaging when small. This article concerns itself with transitional cell carcinomas ...

Transitional cell carcinoma (urinary tract)

Transitional cell carcinoma (TCC), also called urothelial cell carcinoma (UCC), is the most common primary malignancy of the urinary tract and may be found along its entire length, from the renal pelvis to the bladder. As imaging findings and treatment vary according to where along the urinary...

Benign vs malignant features of gallbladder polyps

In most instances predicting benign versus malignant histology of a gallbladder polyp based purely on imaging features is not possible. However, a number of features are helpful in helping to decide the management of a gallbladder polyp. Benign features size polyps that are less than 5 mm in...

Leptomeningeal enhancement

Leptomeningeal enhancement refers to a diffuse or focal gyriform or serpentine enhancement that can be seen in the following conditions: Diffuse meningitis pyogenic meningitis viral meningitis tuberculous meningitis (can also be focal) CNS cryptococcal infection coccidioidal meningitis (c...

Orbital metastasis

Orbital metastases are relatively uncommon, but some primary tumors do have a predilection to metastasize to the orbit. This article concerns itself with extraocular metastases, rather than intraocular tumors or direct extension of tumors from neighboring regions. For a discussion of intraocula...

Hereditary renal cancer syndromes

Despite the vast majority of renal cancers being sporadic, there are a number of hereditary renal cancer syndromes: von Hippel Lindau syndrome: predominantly clear cell type tuberous sclerosis: predominantly clear cell type (also associated with angiomyolipoma) hereditary paraganglioma-pheoch...

Liposclerosing myxofibrous tumor

Liposclerosing myxofibrous tumors (LSMFT), also known as polymorphic fibro-osseous lesions of bone, are rare benign fibro-osseous lesions that have a predilection for the intertrochanteric region of the femur. The histopathological origin of this lesion is unclear and under discussion 1-3. Ter...

Inverted papilloma

Inverted papillomas are a type of Schneiderian papilloma, representing an uncommon non-cancerous sinonasal tumor that mostly affects middle-aged men. They occasionally undergo malignant transformation. On imaging, they classically demonstrate a convoluted cerebriform pattern seen on both T2 and ...

Intraosseous meningioma

Intraosseous meningioma, also referred to as primary intraosseous meningioma, is a rare subtype of meningioma that accounts for less than 1% of all osseous tumors. They are the most common type of primary extradural meningiomas 6. Terminology It is important to note that it has been argued by ...

Optic nerve sheath meningioma

Optic nerve meningiomas are benign tumors 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 tumors typically appear as masses within the optic nerve, iso...

Hypopharyngeal carcinoma (staging)

Hypopharyngeal carcinoma staging refers to TNM staging of carcinomas originating in the hypopharynx. This system most commonly applies to squamous cell carcinomas but can also apply to rarer epithelial malignancies in the region. The following article reflects the 8th edition published by the Am...

Hypopharyngeal squamous cell carcinoma

Squamous cell carcinoma (SCC) of the hypopharynx is relatively uncommon, carries the worst prognosis of any head and neck squamous cell carcinoma (HNSCC), and is a challenge to diagnose and treat. Hypopharyngeal carcinoma is relatively uncommon representing only 10% of all proximal aerodigesti...

Head and neck squamous cell carcinomas

Head and neck squamous cell carcinomas (HNSCC) are the most common histologic type of head and neck cancer. While the term may include any squamous cell carcinoma of the head and neck, common usage focuses on those of mucosal origin, i.e., squamous cell carcinoma of the upper aerodigestive tract...

Head and neck squamous cell carcinoma (overview)

Head and neck squamous cell carcinomas (SCC) are common, being the sixth most common cancer. They can have a cutaneous or mucosal origin. As such there is a wide array of clinical and radiographic manifestations, and are separated into: squamous cell carcinoma of the skin of the head and neck ...

Multiple myeloma

Multiple myeloma (MM), also known as plasma cell myeloma, is a multifocal proliferation of plasma cells based in the bone marrow. It is the most common primary malignant bone neoplasm in adults. It arises from red marrow due to the monoclonal proliferation of plasma cells and manifests in a wide...

Primary malignancy of the nasopharynx

There are a number of primary malignancies of the nasopharynx: nasopharyngeal carcinoma (squamous cell carcinoma): 70% lymphoma (sinonasal lymphoma): 20% other nasopharyngeal papillary adenocarcinoma adenoid cystic carcinoma mucosal melanoma extramedullary plasmacytoma carcinosarcoma fi...

Nasopharyngeal carcinoma

Nasopharyngeal carcinomas (NPC) are the most common primary malignancy of the nasopharynx. They are of squamous cell origin. Some types are strongly associated with the Epstein-Barr virus (EBV). Epidemiology Nasopharyngeal carcinoma accounts for ~70% of all primary malignancies of the nasophar...

Carcinoid tumor

Carcinoid tumors are a type of neuroendocrine tumor that can occur in a number of locations. Carcinoid tumors arise from endocrine amine precursor uptake and decarboxylation (APUD) cells that can be found throughout the gastrointestinal tract as well as other organs (e.g. lung). In general, they...

Orbital lymphoma

Primary lymphoma of the orbit is one of the most common orbital tumors and accounts for as much as half of all orbital malignancies. It is a B-cell non-Hodgkin lymphoma, and in most cases arises from mucosa-associated lymphoid tissue (MALT). Epidemiology Orbital lymphomas account for only 2% o...

Gliosarcoma

Gliosarcoma is a classic variant of glioblastoma (along with epithelioid glioblastoma and giant cell glioblastoma) which, although not a distinct diagnosis, remains recognized in the current (2021) WHO classification of CNS tumors as a variant of glioblastoma 9. They are highly malignant (WHO gr...

Radiation-induced pulmonary fibrosis

Radiation-induced pulmonary fibrosis is the late manifestation of radiation-induced lung disease and is relatively common following radiotherapy for chest wall or intrathoracic malignancies. This article does not deal with the changes seen in the acute phase. Please refer to the article on radi...

Primary mediastinal large B-cell lymphoma

Primary mediastinal large B-cell lymphoma is a distinct entity, recognized in the WHO classification of lymphoma. Epidemiology Primary mediastinal large B-cell lymphoma accounts approximately 5% of large B-cell lymphoma, which is usually disseminated or found in the abdomen. There appears to b...

WHO classification of haematolymphoid tumors

The World Health Organization (WHO) classification of haematolymphoid tumors is the most widely used pathologic classification system for hematopoietic and lymphoid neoplasms. The current revision 1, known as the 5th edition, was published in 2022 and supersedes the 4th edition revised published...

Causes of perfusion defects on a VQ scan

There are several causes leading to a perfusion defect on a VQ scan with an acute pulmonary embolus being only one of them: Vascular causes acute pulmonary embolus previous pulmonary embolus (including fat embolism, thromboembolism, air embolism, tumor) vasculitides affecting the pulmonary v...

Lymphoma

Lymphoma (historically lymphosarcoma was used for diffuse forms of the disease) is a malignancy arising from lymphocytes or lymphoblasts. Lymphoma can be restricted to the lymphatic system or can arise as extranodal disease. This, along with variable aggressiveness results in a diverse imaging a...

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