JPC SYSTEMIC PATHOLOGY

INTEGUMENT SYSTEM

November 2016

I-V15

 

Signalment:  Striped bass

HISTORY:  This fish had a wart-like growth on the dorsum.

HISTOPATHOLOGIC DESCRIPTION:  Scaled skin:  In a focally extensive area, the superficial dermis is markedly thickened up to 2 mm by numerous basophilic, round to polygonal fibroblasts that are up to 300 um in diameter with a basophilic, vacuolated, finely granular cytoplasm that is surrounded by a 10-30 um amphophilic, hyaline wall (lymphocystis cells).  The cells have a markedly enlarged central nucleus with coarsely clumped, fibrillar chromatin and a variably distinct nucleolus.  Frequently, the nucleus is replaced by an amorphous eosinophilic material admixed with a basophilic fibrillar material (degeneration and necrosis).  Frequently lymphocystis cells contain a fibrillar, basophilic material within the peripheral cytoplasm (inclusion material).  Lymphocystis cells are separated by thin bands of connective tissue that contain low numbers of macrophages, lymphocytes, plasma cells and karyorrhectic necrotic debris that extends into the subjacent stratum compactum.

MORPHOLOGIC DIAGNOSIS:  Scaled skin (per contributor):  Fibroblast hypertrophy, focally extensive, marked, with cytoplasmic inclusions and lymphoplasmacytic and histiocytic dermatitis, Striped bass (Morone saxatilis), piscine.

ETIOLOGIC DIAGNOSIS:  Iridoviral dermatitis

CAUSE:  Lymphocystis disease virus (LDV) or piscine iridovirus

CONDITION:  Lymphocystis disease (LD)

GENERAL DISCUSSION: 

PATHOGENESIS: 

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS: 

TYPICAL LIGHT MICROSCOPIC FINDINGS: 

ULTRASTRUCTURAL FINDINGS:

ADDITIONAL DIAGNOSTIC TESTS: 

DIFFERENTIAL DIAGNOSIS:

COMPARATIVE PATHOLOGY: 

References:

  1. Bollinger TK, Mao J, Schock D, Bringham MR, Chinchar VG. Pathology, isolation, and preliminary molecular characterization of a novel iridovirus from tiger salamanders in Saskatchewan. J Wildl Dis. 1999; 35(3): 413-429.
  2. Ellis, AE. Genome analysis of fish lymphocystis disease virus. In: Anders K, Darai G, eds. Fish and Shellfish Pathology. Orlando, FL: Academic Press; 1985: 301-305.
  3. Huang Y, Huang X, Zhang J, Gui J, Zhang Q. Subcellular localization and characterization of G protein-coupled receptor homolog from lymphocystis disease virus isolated in China. Viral Immunology. 2007; 20(1):150-159.
  4. Noga EJ. Fish Disease Diagnosis and Treatment. 2nd ed. St. Louis, MO: Mosby; 2010:171-173.
  5. Roberts RJ. The virology of teleost. In: Fish Pathology. Philadelphia, PA: WB Saunders; 1989: 192-300.
  6. Stoskopf MK. Fish Medicine. Philadelphia, PA: WB Saunders Company; 1993: 276-288.
  7. Wolf K. Lymphocystis disease. In: Fish Viruses and Fish Viral Diseases. Ithaca, NY: University Press; 1988: 268-286.
  8. Wu RH, Tang XQ, Sheng XZ, Zhan WB. Tissue distribution of the 27.8 kDa receptor and its dynamic expression in response to lymphocystis disease virus infection in flounder.  J Comp Path. 2015;153(4):324-332.


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