25,729 articles
Anaplastic ganglioglioma
Anaplastic ganglioglioma (AGG), a former WHO grade III mixed neuronal-glial CNS tumor diagnosis, removed by the 2021 WHO CNS5 classification because molecular testing showed most cases are other tumor types such as pleomorphic xanthoastrocytoma or glioblastoma, IDH-wildtype.
Anaplastic large-cell lymphoma
Anaplastic large-cell lymphoma (ALCL) is an aggressive CD30-positive T-cell non-Hodgkin lymphoma, divided by the WHO into primary cutaneous, ALK-positive, and ALK-negative entities with differing genetics and survival.
Anaplastic lymphoma kinase
Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase gene on 2p23, first cloned in 1994 via the NPM-ALK fusion in lymphoma; EML4-ALK rearrangements drive non-small cell lung cancer and are treated with crizotinib through lorlatinib.
Anaplastic oligoastrocytoma, dual genotype
Anaplastic oligoastrocytoma, dual genotype (ORPHA:251663, ICD-11 2A00.0Y) is a rare IDH-mutant mixed glioma carrying both astrocytic (ATRX/TP53) and oligodendroglial (1p/19q codeletion) markers, retained as a WHO NEC category.
Anaplastic thyroid carcinoma
Anaplastic thyroid carcinoma (ATC), or undifferentiated thyroid cancer, is a rare, aggressive thyroid malignancy in under 2% of cases but up to 50% of thyroid cancer deaths; average survival about 6 months, treated with surgery, radiation, chemotherapy, and dabrafenib-trametinib for BRAF V600E.
Anaprazole sodium
Anaprazole sodium (安奈拉唑钠, trade name Anjiuwei) is a Chinese-developed proton pump inhibitor approved by the NMPA in June 2023 for duodenal ulcer, non-inferior to rabeprazole in phase III trials, with CYP2C19-independent metabolism.
Anarthria
Anarthria (loss of articulate speech) is the complete inability to articulate speech, the most severe form of dysarthria, with comprehension preserved; caused by stroke, ALS, or brainstem injury, ICD-11 code MA80.20.
Anasarca
Anasarca, also called generalized edema, is severe widespread interstitial fluid accumulation caused by disturbed Starling forces, most often from heart failure, nephrotic syndrome, or cirrhosis; treated by addressing the underlying cause with diuretics.
Anastomosing hemangioma
Anastomosing hemangioma (anastomosing haemangioma) is a rare benign capillary-type vascular tumor first described in 2009, occurring mainly in the kidney, retroperitoneum, and ovary, with GNAQ/GNA14 mutations and an angiosarcoma-like histology.
Anastomosis
Anastomosis: a surgical connection between tubular structures such as blood vessels or intestine. Covers types (intestinal, vascular), end-to-end/side-to-side/end-to-side configurations, complications, history from Carrel to robotics.
Anastomotic urethroplasty
Anastomotic urethroplasty, also called excision and primary anastomosis (EPA), treats urethral stricture by cutting out the narrowed segment and joining the healthy urethral ends without tension.
Anastrozole
Anastrozole (Arimidex) is a nonsteroidal third-generation aromatase inhibitor, 1 mg daily, approved in the US in 1995 for postmenopausal hormone receptor-positive breast cancer and studied for prevention.
Anatomic resection
Anatomic resection, also called anatomic lung resection, is surgery that removes an organ together with its anatomically defined segment, dividing the segmental bronchus, artery, and vein.
Anatomical plane
Anatomical plane: imaginary flat surfaces (sagittal, coronal/frontal, transverse/axial, oblique) through the body in the anatomical position, used to divide the body into sections and standardize descriptions in anatomy, CT, MRI, and ultrasound.
Anatomical resection
Anatomical resection, also known as anatomical liver resection, is a surgical technique that removes tumors along defined anatomical boundaries, such as the liver's eight Couinaud segments or the lung's bronchopulmonary segments.
Anatomical snuffbox
Anatomical snuffbox (radial fossa, radial foveola): triangular depression on the dorsum of the hand at the wrist, bounded by thumb extensor tendons, floored by the scaphoid, containing the radial artery; site of scaphoid fracture tenderness and distal radial access.
Anatomical terminology
Anatomical terminology: the standardized Latin-based nomenclature for human body structures, maintained by FIPAT of the IFAA, descended from the 1895 Basle Nomina Anatomica, currently the Terminologia Anatomica 2nd edition (2019).
Anatomical terms of location
Anatomical terms of location: standardized directional terms (anterior, medial, superior, proximal) defined against the anatomical position, governed by Terminologia Anatomica since 1895's Basiliensia Nomina Anatomica.
Anatomical terms of motion
Anatomical terms of motion: flexion, extension, abduction, adduction, rotation, circumduction, and special movements, defined relative to anatomical position and the sagittal, frontal, and transverse planes, standardized by FIPAT's Terminologia Anatomica.
Anatomical terms of muscle
Anatomical terms of muscle: standardized Latin and English muscle names in Terminologia Anatomica (TA, 1998; TA2, 2019), covering naming by shape, size, location, function, origin/insertion, and parallel versus pennate fiber architecture.
Anatomical Therapeutic Chemical Classification System
The WHO Anatomical Therapeutic Chemical (ATC) classification system codes active substances in five levels across 14 main groups (e.g., metformin A10BA02) for drug utilization research; developed in Norway from EPhMRA, maintained in Oslo, paired with the Defined Daily Dose.
Anauxetic dysplasia
Anauxetic dysplasia (ANXD, OMIM 607095), also called spondyloepimetaphyseal dysplasia, anauxetic or Menger type: a rare autosomal recessive RMRP-related skeletal dysplasia with prenatal-onset extreme short stature, adult height under 1 meter, and fewer than ten reported cases.
Anbenitamab repodatecan
Anbenitamab repodatecan (development code JSKN003) is an antibody-drug conjugate against HER2, developed by Alphamab Oncology and in phase III trials for breast, ovarian, and colorectal cancers.
ANCHOR trial
ANCHOR (NCT01047501) was Amarin's phase 3, 12-week, randomized trial of icosapent ethyl (AMR101/Vascepa) in 702 statin-treated patients with triglycerides 200-499 mg/dL; it met its lipid endpoints but the FDA rejected the ANCHOR indication.
Ancrod
Ancrod (Arvin, Viprinex) is a thrombin-like enzyme from Malayan pit viper venom that defibrinogenates blood by cleaving fibrinopeptide A; tested for acute ischemic stroke in STAT and ESTAT trials, never US-approved, production discontinued in 2002.
Andamertinib
Andamertinib (安达艾替尼, brand 安比锐) is an oral, irreversible EGFR tyrosine kinase inhibitor by Avistone for EGFR exon 20 insertion-mutant NSCLC; approved in China April 2026 after the phase 2 KANNON study showed 42.7% response rate.
Andecaliximab
Andecaliximab (GS-5745), a Gilead-developed humanized IgG4 monoclonal antibody inhibiting MMP-9, failed phase 2/3 trials in ulcerative colitis, Crohn's disease, and gastric cancer (GAMMA-1), and is now in the ANDECAL trial for fibrodysplasia ossificans progressiva.
Andersen-Tawil syndrome
Andersen-Tawil syndrome (ATS, LQT7, Andersen syndrome) is a rare autosomal dominant channelopathy with periodic paralysis, ventricular arrhythmias, and dysmorphic features, caused by KCNJ2 mutations in about 60% of cases.
ANDES trial
ANDES (NCT03568890) is a cardiology randomized trial comparing 60 days of DOACs versus dual antiplatelet therapy after left atrial appendage closure: similar device thrombosis (1.5% vs 4.1%), fewer bleeding events with DOACs. Distinct from the ANDES HIV and Peru hypertension trials.
Andexanet alfa
Andexanet alfa (Andexxa, Ondexxya) is a recombinant inactive factor Xa decoy protein reversing apixaban and rivaroxaban anticoagulation; FDA accelerated approval 2018, withdrawn from the US market December 2025 over thrombotic risk.