JPC SYSTEMIC PATHOLOGY

INTEGUMENTARY SYSTEM

September 2016

I- N05

 

Signalment (JPC 2005790):  Young broiler chicken

HISTORY:  This chicken had multiple ulcerative dermal lesions noted at slaughter.

HISTOPATHOLOGIC DESCRIPTION:  Feathered skin:  Diffusely, the epidermis is absent (scalding artifact).  Multifocally infiltrating and replacing the dermis and subcutis is an unencapsulated, poorly circumscribed, ulcerated, crateriform neoplasm  composed of poorly defined cords and islands of polygonal cells on an abundant fibrovascular stroma composed of reactive fibroblasts (desmoplasia) with scattered heterophils, lymphocytes, and plasma cells.  Polygonal cells have variably distinct cell borders, an abundant amount of intensely eosinophilic to globular cytoplasm, irregularly oval vesiculate nuclei and one to two prominent nucleoli.  Mitoses average one per HPF.  Neoplastic cells frequently undergo dyskeratosis, and rarely surround islands of brightly eosinophilic keratin (keratin pearls). Multifocally there are areas of cellular loss (necrosis) and heterophils and macrophages infiltrating adjacent adipose tissue.  Focally, there is a hyperplastic feather follicle with abundant keratin surrounded by a thickened epithelium with rare intercellular edema (spongiosis), and mild orthokeratotic hyperkeratosis. Lymphatics are multifocally dilated (edema) and vessels often contain aggregates of heterophils.

MORPHOLOGIC DIAGNOSIS:  Feathered skin: Keratoacanthoma, breed unspecified, chicken, avian.

CONDITION:  Avian keratoacanthoma

SYNONYMS:  Dermal squamous cell carcinoma; squamous epithelioma

GENERAL DISCUSSION:

PATHOGENESIS:

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS:

TYPICAL LIGHT MICROSCOPIC FINDINGS:

ULTRASTRUCTURAL FINDINGS:

DIFFERENTIAL DIAGNOSIS:

COMPARATIVE PATHOLOGY:

Lab animals have two experimental types

REFERENCES:

  1. Eydner M, Jacobsen B, Thomann M, Rittinghausen S, Fehr M, Baumgärtner W. Spontaneously occurring multicentric basal cell carcinoma and keratoacanthomas in a multimammate mouse (Mastomys spp.). J Vet Diagn Invest. 2012; 24(4):696-701.
  2. García-Fernández RA, Pérez-Martínez C, García-Iglesias MJ. In vivo long-term effects of retinoic acid exposure in utero on induced tumours in adult mouse skin. Vet Dermatol. 2014; 25(6):538-546.
  3. Hargis AM, Myers S. The integument. In: Zachary JF, ed. Pathologic Basis of Veterinary Disease. 6th St. Louis, MO: Mosby Elsevier; 2016: 1105.
  4. Haschek WM, Rousseaux CG, Walling MA. Fundamentals of Toxicologic Pathology. 2nd Burlington, MA: Elsevier; 2010: 156.
  5. Maudlin EA, Peters-Kennedy J. Integumentary system. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 1. 6th ed. Philadelphia, PA: Elsevier Saunders; 2016: 702.   
  6. Owen HC, Donely RJ, Schmidt RE, Patterson-Kane JC. Keratoacanthoma causing beak deformity in a budgerigar (Melopsittacus undulates).  Avian Pathol. 2007; 36(6):499-502.
  7. Pesaro S, Biancani B, Fabrizi G, Rossi G. Squamous cell carcinoma with presence of poxvirus-like inclusions in the foot of a pink-backed pelican (Pelecanus rufescens).  Avian Pathol. 2009; 38(3)229-231.
  8. Schat KA, Nair V. Neoplastic diseases. In: Swayne DE, et al. eds. Diseases of Poultry. 13th ed. Ames, IA: Wiley-Blackwell; 2013: 617-618.
  9. Sivaprasad HL, Barnes HJ. Integumentary system. In: Abdul-Aziz T, Fletcher OJ, Barnes HJ, eds. Avian Histopathology. 4th ed. Jacksonville, FL: American Association of Avian Pathologists; 2016: 624,639.


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