Human health and medicine

Gynandroblastoma

Gynandroblastoma, a rare mixed ovarian sex cord-stromal tumor with both granulosa cell (female) and Sertoli-Leydig (male) differentiation; under 1% of sex cord tumors, often DICER1-mutated, FOXL2-wild-type, usually benign.

Gynecologic laparoscopy

Gynecologic laparoscopy is a minimally invasive surgical technique in which a laparoscope and instruments are inserted through small abdominal incisions to diagnose and treat conditions of the female reproductive organs.

Gynecologic oncology

Gynecologic oncology is the medical subspecialty devoted to cancers of the female reproductive tract, including the cervix, endometrium, fallopian tubes, ovaries, uterus, and vagina. Its practitioners complete fellowship training after obstetrics and gynecology residency.

Gynecologic Oncology Group

Gynecologic Oncology Group (GOG), also GOG Foundation, Inc.: American NCI cooperative group founded 1970 for gynecologic cancer trials; landmark trials GOG-33, GOG-111, GOG-0218, GOG-240; successor entities GOG Foundation and NRG Oncology.

Gynecologic Surgical Procedures

Gynecologic surgical procedures are operations on the female genitalia (MeSH D013509), spanning hysterectomy, myomectomy, ovariectomy, and hysteroscopy, performed open, vaginally, laparoscopically, robotically, or via vNOTES.

Gynecomastia

Gynecomastia is benign enlargement of male breast glandular tissue from estrogen excess, androgen deficiency, or drugs, peaking in neonates, puberty, and older men; treated by addressing causes, tamoxifen for recent cases, or surgery.

Gynophobia

Gynophobia (gynephobia, gynaephobia) is a specific phobia of women, ICD-10-CM F40.291; ICD-11 lists it under social anxiety disorder. Treated by exposure therapy; distinct from misogyny.

Gyrate atrophy of choroid and retina

Gyrate atrophy of the choroid and retina (GACR), gyrate atrophy, hyperornithinemia: rare autosomal recessive retinal degeneration from OAT gene deficiency causing elevated ornithine, night blindness, spiral chorioretinal atrophy, treated with arginine-restricted diet.

Oct 20, 2026

H syndrome

H syndrome (SLC29A3 spectrum disorder, histiocytosis-lymphadenopathy plus syndrome) is a rare autosomal recessive genodermatosis caused by SLC29A3 mutations, marked by hyperpigmented hypertrichotic indurated thigh plaques, hearing loss, short stature, and diabetes.

H. pylori eradication therapy

H. pylori eradication therapy combines antibiotics, usually with bismuth and an acid-suppressing drug, taken for about two weeks to cure H. pylori infection and peptic ulcers.

H1 antagonist

H1 antagonist (H1-antihistamine): inverse agonist drug blocking histamine at the H1 receptor; first synthesized 1937 by Bovet; first-generation (1942 onward) sedating, second-generation (cetirizine, loratadine, fexofenadine) non-sedating first-line for rhinitis and urticaria.

H3B-6545

H3B-6545 is Eisai's oral selective estrogen receptor covalent antagonist (SERCA) that covalently binds C530 of ERalpha, inhibiting wild-type and mutant receptor in ER+/HER2- breast cancer; phase 1/2 testing showed 450 mg QD with ORR 20.2% and higher activity in ESR1 Y537S-mutant disease.

Habit reversal training

Habit reversal training is a behavioral therapy that treats tics, nervous habits, and body-focused repetitive behaviors by training patients to detect the behavior early and perform an incompatible competing response.

Habituation

Habituation: progressive decrease of a response to repeated stimulation, not caused by sensory adaptation or fatigue; distinguished by dishabituation, stimulus specificity, and spontaneous recovery; HPA axis habituates rapidly to repeated stress.

HACP trial

HACP trial (NCT02368678), Study of Halitosis in Patients With Advanced Chronic Periodontitis: Brazilian randomized trial comparing full-mouth disinfection with quadrant scaling; both reduced halitosis at 90 days, FMD showing the larger methyl mercaptan reduction.

Hadron therapy

Hadron therapy is a radiation treatment using charged particle beams, chiefly protons and carbon ions, which deposit most of their energy in the tumor while sparing healthy tissue.

Haematemesis

Haematemesis is vomiting of blood, fresh or coffee-ground, signaling upper gastrointestinal bleeding from the esophagus, stomach, or duodenum. Key facts: peptic ulcers cause 43.6% of cases; Glasgow Blatchford score 1 or less identifies outpatient-manageable patients.

Haematococcus pluvialis astaxanthin extract

Haematococcus pluvialis astaxanthin extract: oleoresin from the green microalga H. pluvialis, the richest natural astaxanthin source (up to 5.5% dry weight); FDA GRAS (GRN 294, 580), EU novel food limit 8 mg/day.

Oct 20, 2026

Haematocolpos

Haematocolpos, also spelled hematocolpos, is the accumulation of menstrual blood in the vagina caused by an obstruction, most often an imperforate hymen, and typically appears at puberty.

Haematologica

Haematologica: monthly open-access hematology journal founded 1920 in Naples by Ferrata and Moreschi, oldest hematology journal, owned by the Ferrata Storti Foundation, official EHA journal, 2025 Impact Factor 8.2.

Haematoma of broad ligament

Broad ligament haematoma: blood collecting in the broad ligament of the uterus, a rare obstetric emergency (incidence about 1:500 to 1:20,000) caused by tears extending into uterine or vaginal vessels, treated conservatively or surgically.

Haematometra

Haematometra (hemometra, haemometra) is retention of blood in the uterine cavity, usually from outflow obstruction such as imperforate hymen, transverse vaginal septum, or cervical stenosis after procedures; treated by cervical dilatation and drainage.

Haematopoiesis

Haematopoiesis, also spelled hematopoiesis and known as blood formation or haemogenesis, is the process by which blood cells form from stem cells, primarily in adult bone marrow.

Haematosalpinx

Haematosalpinx (hematosalpinx, haemosalpinx), blood accumulation in a distended fallopian tube; ICD-11 GA17.3. Most often from ectopic pregnancy; also endometriosis, PID, torsion, neoplasm. Diagnosed by ultrasound and MRI.

Haematuria

Haematuria, also spelled hematuria, is the presence of blood in the urine, classified as visible when it discolors the urine and non-visible when found only on testing.

Oct 20, 2026

Haemoglobinuria

Haemoglobinuria (hemoglobinuria, hemoglobin in urine) is free hemoglobin in urine from intravascular red cell hemolysis after haptoglobin saturation; dipstick positive without red cells; causes include PNH, malaria, burns, and march hemoglobinuria.

Haemolytic uraemic syndrome

Haemolytic uraemic syndrome (Gasser syndrome, ICD-11 3A21.2), a thrombotic microangiopathy with thrombocytopenia, hemolytic anemia, and kidney injury; usually Shiga toxin E. coli, sometimes complement-mediated aHUS.

Haemoperitoneum

Haemoperitoneum (hemoperitoneum, intraperitoneal hemorrhage) is blood accumulating in the peritoneal cavity from internal bleeding. Causes are traumatic (liver, spleen), spontaneous (ectopic pregnancy, ruptured aneurysm, ovarian cyst), or iatrogenic; ICD-10 K66.1, ICD-11 DC51.2.

Haemophilia

Haemophilia, an inherited X-linked bleeding disorder from factor VIII (haemophilia A) or factor IX (haemophilia B, Christmas disease) deficiency; affects about 1 in 5,000 male births, treated with factor replacement, emicizumab, and AAV gene therapy.