Ground Glass Appearance

Ground Glass Appearance

A descriptor for a homogenous translucency in radiology, microbiology, or histology, which may obscure cellular detail, equivalent to German milchglassartig
Bacteriology The ground glass appearance (GGA) refers to a shadowy pattern seen on culture plates that is midway between the greenish hue of alpha haemolysis, and the ochre-brown of beta-haemolysis, which is incorrectly termed gamma-hemolysis. A GGA is typically see on older colonies of Bacillus anthracis
Cytology A GGA is a classic finding in herpes infection of the oesophagus, uterine cervix and elsewhere, in which infected cells are multinucleated and the nuclei themselves appear hazy and without discrete clumps of chromatin
Haematology GG histiocytes have ‘washed-out’ cytoplasm and are typical of reticulocytic granuloma
Imaging—abdomen A GGA with haziness and erasure of organ silhouettes is typical of massive ascites, as seen on plain films of the abdomen, and due to an increased water density and peritonitis
Imaging—bone The GGA corresponds to a relatively uniform loss of osseous density which may be accompanied by intravascular calcification and subcutaneous ossification, seen in bones affected by fibrous dysplasia, scurvy—located at the epiphyses—osteomalacia, agnogenic myeloid metaplasia, and osteoporosis
Imaging—chest The GGA corresponds to an alveolar, acinar or amorphous pattern seen in bronchiolitis obliterans and obstructive pneumonia (BOOP) by plain films. It can also be seen by CT and may reflect minimal thickening of the septal or alveolar interstitium, thickening of alveolar walls, or the presence of cells or fluid filling the alveolar spaces. In an acute setting (see below), it can represent active disease such as pulmonary edema, pneumonia, or diffuse alveolar damage
Imaging—pediatric The GGA refers to poorly circumscribed radiopacifications of the right lower quadrant, mixed with fine trapped bubbles within the meconium ‘plug’, seen on a plain film in meconium ileus
Ophthalmology GG opacification of cornea occurs in children with mucopolysaccharidosis (MPS) type I-H or Hurler syndrome, with global MPS deposition in the ocular structures, photophobia, retinal degeneration, attenuation of vessels, optic atrophy, loss of vision, hydrocephalus
Pathology GGA refers to uniform, finely granular eosinophilic—orcein & aldehyde fuchsin positive—cytoplasm with a peripheral clear halo; a similar morphology may be seen in dilated lysosomes in Gaucher disease, or in the lung with viral inclusions, which by electron microscopy reveal spherules of HBsAg; similar PAS-positive inclusions may be seen in alcoholics treated with disulfiram or Antabuse, an acetaldehyde dehydrogenase inhibitor
Pathology—brain GG cytoplasm is characteristic of gemistocytic cells in astrocytomas
Pathology—liver GGA occurs in the cytoplasm of HBV-infected liver cells due to swelling of smooth endoplasmic reticulum
Pathology—pancreas A GGA is typical of the abolished architectural details seen by low-power LM in enzymatic fat necrosis or in postmortem autolysis
Virology The GGA is seen in nuclei of epithelial cells infected with herpes simplex

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ground glass appearance

A descriptor for a homogenous translucency in radiology, microbiology, or histology, which may obscure cellular detail Ophthalmology GG opacification of cornea occurs in children with mucopolysaccharidosis–MPS type I-H or Hurler syndrome, with global MPS deposition in the ocular structures, photophobia, retinal degeneration, attenuation of vessels, optic atrophy, loss of vision, hydrocephalus Radiology, abdomen A GGA with haziness and erasure of organ silhouettes, is typical of massive ascites, and related to an ↑ water density and peritonitis Radiology, bone The GGA corresponds to a relatively uniform loss of osseous density which may be accompanied by intravascular calcification and subcutaneous ossification, seen in bones affected by fibrous dysplasia, scurvy–located at the epiphyses, osteomalacia, agnogenic myeloid metaplasia, and osteoporosis Radiology, chest The GGA corresponds to an alveolar, acinar or amorphous pattern seen in bronchiolitis obliterans and obstructive pneumonia–BOOP