onion skin appearance
Haematology A term referring to the concentric fibrosis of splenic central and penicilliary arteries, which is seen in systemic lupus, thrombocytopenic purpura, or the lymph nodes in Castleman’s disease and other conditions
Imaging—bone A term referring to laminated lytic and sclerotic periosteal reaction seen on plain films. While the reaction has been described in benign conditions—e.g., osteomyelitis, pulmonary hypertrophic osteoarthropathy, rickets, it classically occurs in malignant conditions, especially Ewing sarcoma, which is characterised by delicate laminations with periosteal layering; coarse laminations are more characteristic of osteosarcoma
Nephrology Onion skin' changes correspond to the concentric arterial thickening with progressive luminal narrowing, due to hyperplasia of smooth muscle cells and basement membrane reduplication, which may be accompanied by necrosis and fibrinoid deposits—necrotizing arteriolitis—and ischemic damage with renal involvement; similar changes may occur in the gallbladder, periadrenal fat, peripancreatic intestinal arterioles. Extensive onion skinning is classically associated with malignant hypertension
Neuropathology Onion bulb appearance A term referring to the characteristic layering of connective tissue around the periaxon seen by light microscopy in Dejerine-Sottas disease—hereditary motor and sensory polyneuropathy type III—which is characterised by infantile onset of moderate to severe lower and upper extremity weakness and loss of sensation that spreads centrifugally; in the peripheral nervous system, ‘onion skinning’ may be due to repetitive myelination and demyelination, in large peripheral myelinated nerves in Charcot-Marie-Tooth, especially in CMT type 1 and in Roussy-Levy syndrome, a variant of CMT type 1A
Obstetrics The term onion-skinning was used in the past for laminated pockets of myometrial gas seen in septic abortions—an event of now historic interest, especially due to Clostridium perfringens; despite severity of clinical disease, hysterectomy may not be necessary, if the uterine cavity is curetted and antibiotic therapy is adequate
Pathology—liver Onion skinning in the liver refers to concentric lamellar fibrosis surrounding medium-sized bile ducts in the portal spaces of livers with sclerosing cholangitis, which may be accompanied by aggregates of lymphocytes, germinal centre and granuloma formation
Pathology—stomach onion skin appearance has been described in concentric perivascular fibroblasts and collagen seen by the Masson trichrome stain in gastric inflammatory fibroid polypss
Sports medicine Weight athlete slang for skin and subcutaneous tissue that is so thin that it’s been likened to onionskin
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.
onion skin appearanceA pattern characterized by concentric laminations of differing radiologic or histologic densities
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.