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Pantothenic acid
Pantothenic acid, or vitamin B5, is a water-soluble vitamin precursor of coenzyme A, found in nearly all foods; adults need 5 mg/day, deficiency is rare, and no toxic upper limit is set.
Pantothenic acid deficiency
Pantothenic acid deficiency (vitamin B5 deficiency, ICD-11 5B5H), a rare condition from severe malnutrition or metabolic antagonists, causing burning feet, fatigue, insomnia, and gastrointestinal symptoms.
PANUC study
PANUC study: baseline characterization of the Pacific Northwest Udall Center Clinical Consortium, a 619-participant Parkinson's disease cohort (Seattle, Portland, Cincinnati) with 22% dementia, 59% mild cognitive impairment, and a male excess of impairment.
Panvax
Panvax is Seqirus's inactivated, split-virion pandemic influenza vaccine family: an H1N1 pandemic vaccine (TGA-registered 2008, WHO prequalified 2009) plus H5N1 and H5N8 pre-pandemic variants, egg-produced with aluminium phosphate adjuvant.
Paolo Macchiarini
Paolo Macchiarini, Italian thoracic surgeon, performed the first synthetic stem-cell-seeded trachea transplants at Karolinska (2011–2014); patients died, he was found guilty of research misconduct, and in 2023 received a 2.5-year Swedish prison sentence.
Pap test
Pap test (Papanicolaou test, Pap smear, cervical cytology): screening exam of cervical cells under a microscope to detect precancerous changes; introduced by Papanicolaou in 1928, recommended every 3 years from age 21.
PAPA syndrome
PAPA syndrome (pyogenic arthritis, pyoderma gangrenosum, and acne; familial recurrent arthritis) is a rare autosomal dominant autoinflammatory disease caused by PSTPIP1 mutations on chromosome 15, driving IL-1β overproduction and treated with anakinra and TNF inhibitors.
PAPASH syndrome
PAPASH syndrome (pyogenic arthritis-pyoderma gangrenosum-acne-hidradenitis suppurativa syndrome, ORPHA:641380) is a rare autoinflammatory disorder first reported in 2013, with about 14 cases, sometimes linked to PSTPIP1 mutations and treated with IL-1, TNF-alpha, or IL-17 biologics.
PAPAudit study
PAPAudit (NCT04812938) is a retrospective Italian observational study testing whether clonal TP53 mutations of high-grade serous ovarian cancer can be detected in archival Pap test DNA years before diagnosis, validating the 2020 Paracchini cohort.
Papaverine
Papaverine, a benzylisoquinoline opium alkaloid discovered by Georg Merck in 1848, is a smooth-muscle relaxant and vasodilator (PDE inhibitor) used for vascular spasm and in intracavernosal injection mixtures for erectile dysfunction, without narcotic effects.
Papillary conjunctivitis
Papillary conjunctivitis: conjunctival inflammation with vascular papillae on the tarsal conjunctiva, mainly allergic, drug-induced, or mechanical; giant papillary conjunctivitis (GPC) is the contact lens form, first described by Spring in 1974.
Papillary glioneuronal tumor
Papillary glioneuronal tumor (PGNT), a rare WHO grade I mixed glial-neuronal brain tumor of young adults with SLC44A1::PRKCA fusion, pseudopapillary histology, and favorable prognosis after gross total resection.
Papillary hemangioma
Papillary hemangioma (papillary capillary hemangioma, ORPHA:673543) is a rare benign cutaneous vascular tumor of the head and neck with intraluminal papillary projections and hyaline globules; it harbors GNAQ/GNA11 Q209L mutations and must be distinguished from glomeruloid hemangioma of POEMS syndrome.
Papillary intralymphatic angioendothelioma
Papillary intralymphatic angioendothelioma (PILA, Dabska tumor), a rare low-grade lymphatic vascular tumor of skin and subcutis in children and young adults, first described 1969, treated by wide excision, rarely metastasizing.
Papillary renal cell carcinoma
Papillary renal cell carcinoma, also called PRCC, is a kidney cancer arising in the lining of the kidney's tubules, the second-most common form of renal cell carcinoma.
Papillary thyroid cancer
Papillary thyroid carcinoma (PTC), the most common thyroid cancer, arises from thyroid follicular cells, grows slowly, affects women more, often before age 45; driven by BRAF V600E and RET fusions, with active surveillance an option for low-risk tumors.
Papillary tumor of the pineal region
Papillary tumor of the pineal region (PTPR), a rare WHO grade 2-3 neuroepithelial tumor near the pineal gland, first described 2003, arising from subcommissural organ ependymal cells, with high local recurrence and 73% 5-year survival.
Papilledema
Papilledema is optic disc swelling caused by elevated intracranial pressure, usually bilateral. Most common cause is idiopathic intracranial hypertension; diagnosed with MRI/MRV, lumbar puncture, and OCT; treated with acetazolamide, weight loss, or shunting.
Papilloedema
Papilloedema (papilledema) is optic disc swelling from raised intracranial pressure, most often idiopathic intracranial hypertension; almost always bilateral, an emergency requiring neuroimaging, and detectable on fundus photos by AI with ~95% sensitivity.
Papilloma
Papilloma: a benign epithelial tumor, usually exophytic; also called condyloma when HPV-caused on genitals. Covers squamous papillomas, warts, and HPV-independent forms like intraductal papilloma.
Papillomatosis
Papillomatosis (in crocodiles), or crocodile pox, is a poxvirus skin disease of farmed crocodilians, mainly hatchlings under two years, causing papular lesions that downgrade hides; non-WOAH-listed, reported voluntarily.
Papular elastorrhexis
Papular elastorrhexis, also called disseminated nevus anelasticus, is a rare acquired dermal elastic tissue disorder with multiple small firm hypopigmented papules on the trunk and proximal limbs, fragmented elastic fibers on histology, no systemic involvement, and no established treatment.
Papular mucinosis of infancy
Papular mucinosis of infancy, or cutaneous mucinosis of infancy, is a rare benign pediatric form of localized lichen myxedematosus with firm opalescent mucinous papules on the upper arms and trunk, first described by Lum in 1980.
Papular urticaria
Papular urticaria (insect bite-induced hypersensitivity, lichen urticatus) is a chronic hypersensitivity reaction to insect and arachnid bites causing recurrent itchy papules, mainly in children aged 1–6, common in the tropics; tolerance usually develops by age 7.
Papular xanthoma
Papular xanthoma (PX) is a rare normolipemic non-Langerhans cell histiocytosis with solitary or disseminated yellow-orange papules of xanthomatized macrophages and Touton giant cells, first described by Winkelmann in 1980, self-healing in children.
Papule
Papule: a solid, elevated, palpable skin lesion ≤1 cm in diameter, a primary lesion in dermatology; examples include warts, nevi, lichen planus, acne, and insect bites; distinguished from plaque and nodule by size.
Papulonecrotic tuberculid
Papulonecrotic tuberculid (tuberculosis papulonecrotica) is a rare cutaneous tuberculid: symmetric recurrent necrotizing papules on the limbs from hypersensitivity to M. tuberculosis, Mantoux-positive, healed by antituberculous therapy.
Papulopustular acne
Papulopustular acne (ICD-11 ED80.2), also called pustular or superficial inflammatory acne, is acne dominated by small inflammatory papules and pustules under 5 mm, treated with topical benzoyl peroxide, retinoids, and fixed-dose combinations.
Papulopustular rosacea
Papulopustular rosacea (subtype 2 rosacea) is chronic central facial inflammation with persistent erythema plus transient papules and pustules, without comedones; treated first-line with topical metronidazole, azelaic acid, or ivermectin.
Papyraceous fetus
Papyraceous fetus (fetus papyraceus, fetus compressus): a dead twin mummified and flattened like parchment, retained in utero after early second-trimester demise, occurring in about 1 in 12,000 pregnancies, with risks to the surviving co-twin.