hyaline bodies


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hy·a·line bod·ies

homogeneous eosinophilic inclusions in the cytoplasm of epithelial cells; in renal tubules, hyaline bodies represent droplets of protein reabsorbed from the lumen.
See also: Mallory bodies, drusen.
Synonym(s): fuchsin bodies (2)

hyaline bodies

Etymology: Gk, hyalos + AS, bodig
1 the residue of colloidal degeneration found in some cells.
2 globules of neurosecretory material found in the posterior lobe of the pituitary.
3 deposits of homogenous eosinophilic material found in renal tubular epithelium and representing excess protein molecules that cannot be metabolized or transported.

hy·a·line bod·ies

(hī'ă-lēn bod'ēz)
Homogeneous eosinophilic inclusions in the cytoplasm of epithelial cells; in renal tubules, hyaline bodies represent droplets of protein reabsorbed from the lumen.
See also: Mallory bodies, drusen

drusen

Small, circular, yellow or white dots located throughout the fundus but more so in the macular region, around the optic disc or the periphery. They consist of deposits of abnormal extracellular material (amyloid P, complement proteins (C3, C5, C5b-9 complex), factors C, apolipoproteins B and E, lipids, vitronectin, etc.) derived mainly from the retinal pigment epithelium (RPE) and neural retina and they are located between the basement membrane of the RPE and Bruch's membrane. Drusen interfere with the blood supply to the photoreceptors. Although they may be found in young people, they almost universally occur with ageing but also with retinal and choroidal degeneration (e.g. age-related maculopathy, retinitis pigmentosa, angioid streaks) and primary dystrophy (e.g. fundus flavimaculatus). There are several main types of drusen: (1) Hard (or nodular) drusen are small, round and discrete. They are deposits of granular material as well as of abnormal collagen. They are the most common type and are usually innocuous. (2) Soft (or diffuse or granular) drusen are often large with indistinct edges and with time they may enlarge, coalesce and increase in number. They are due to either a focal thickening of the inner layer of Bruch's membrane or to amorphous material located between that thickened, detached part and the rest of Bruch's membrane. They represent an early feature of age-related macular degeneration. (3) Cuticular (or basal laminar) drusen are small subretinal nodular thickening of the basement membrane of the pigment epithelium. They occur in younger patients more often than hard or soft drusen. (4) With time, the above drusen may calcify (calcific drusen) and take on a glistening appearance. Drusen rarely produce any symptoms and if there is a visual loss it is usually due to an accompanying macular haemorrhage, but if the drusen are very large thus widening the separation between the RPE and Bruch's membrane there may be a degeneration of the overlying RPE and photoreceptors (Fig. D11). Syn. colloid bodies; hyaline bodies. See age-related macular degeneration; choroidal naevus.
familial dominant drusen An autosomal dominant hereditary degeneration of the choroid characterized by light-coloured patches of colloid material in the area around the macula and often the optic disc. The majority of cases are caused by mutations in the EFEMP1 gene (egf-containing fibulin-like extracellular matrix protein 1). There is no loss of vision unless it is followed by macular degeneration. Syn. Doyne's honeycomb choroiditis; Doyne's honeycombed degeneration; Tay's choroiditis (used more commonly for the elderly).
optic disc drusen Whitish-yellow spherical excrescences that lie on, or within, or occasionally around the optic nerve head. They are composed of calcified hyaline-like material possibly resulting from deposition of mucoprotein and calcium that have extruded from degenerating axons. In childhood they are usually buried within the disc substance and thus not visible on clinical examination but cause elevation of the disc surface resembling papilloedema. With age they become progressively more superficial. Field defects are common (e.g. generalized constriction, blind spot enlargement) but visual acuity is normal, unless there is some vascular complication. They usually appear bilaterally and affect males and females equally. They are easily diagnosed with fluorescein angiography because exposed drusen are autofluorescent.
Fig. D11 Calcified drusenenlarge picture
Fig. D11 Calcified drusen