Amyloid associated with neoplasia in two captive tricolour sharkminnows Balantiocheilus melanopterus Bleeker

Abstract

Amyloid associated with pancreatic adenocarcinoma was discovered in two captive adult tricolour sharkminnows Balantiocheilus melanopterus Bleeker found dead in a freshwater display. Enlarged abdomens expanded by bloody ascitic fluid and grossly visible masses of abnormal tissue were present surrounding sections of the stomach and intestine. Histologically, the masses were composed of areas of well-organized exocrine pancreatic acini interspersed with cords of poorly differentiated, spindle-shaped cells that compressed and effaced normal parenchyma. These cells possessed small numbers of cytoplasmic zymogen granules; the exocrine nature of these cells was confirmed using transmission electron microscopy (TEM). Fibrovascular connective tissue of the hepatopancreas and mesenteries was expanded by lightly eosinophilic, hyaline, homogeneous acellular material. Similar material greatly expanded the tunica media of large blood vessels in the hepatopancreas. After staining with Congo red or thioflavin T, this material exhibited red-green dichroism under polarized light or bright green fluorescence under ultraviolet light (255 nm), respectively. The non-branching fibrils, of indeterminate length, had an approximate diameter of 10-20 nm using TEM. Although exocrine pancreatic neoplasia is relatively common in fish, the presence of amyloid is not. To our current knowledge, the latter has not yet been described in association with a neoplastic lesion in fish.

Amyloid‐like renal lesions in a roughtail stingray Dasyatis centroura (Mitchill 1815)

“…Amyloid stained by Congo red is pink to red in ordinary light, but typically produces green birefringence when polarized (Pepys 2006;Herrera & Turbat-Herrera 2010;Kumar et al 2010). Congo red failed to produce birefringence in this case, although it has been previously observed in two teleost species (Mashima et al 1997;Russell et al 2014). Similarly, fluorescence characteristic of amyloid was not produced in kidney sections stained with Thioflavin-T (Vowles 2008).…”

“…Amyloidosis has not been previously reported in elasmobranchs and only rarely in teleost fishes (Mashima, Cornish & Lewbart ; Russell et al . ).…”

“…; Russell et al . ). Similarly, fluorescence characteristic of amyloid was not produced in kidney sections stained with Thioflavin‐T (Vowles ).…”

“…While urine protein was not assayed, severe proteinuria is likely, based on the extensive glomerular amyloid deposition and diffuse foot process effacement. Amyloidosis has not been previously reported in elasmobranchs and only rarely in teleost fishes (Mashima, Cornish & Lewbart 1997;Russell et al 2014). Diagnosis of amyloidosis depends on the light and electron microscopic appearance of lesions and fibrils, respectively.…”

Epitheliocystis in lake trout Salvelinus namaycush (Walbaum) is associated with a β‐proteobacteria

“…Tissue was post‐fixed in 1% osmium tetroxide and processed for transmission electron microscopy (TEM) (Russell et al . ) and examined on a Hitachi H7100 transmission electron microscope (Hitachi High‐Tech Science Systems Inc) at 75kv.…”