JPC SYSTEMIC PATHOLOGY
SPECIAL SENSES
April 2018
S-M15 (NP)

Signalment (JPC #1722833):  1-year-old sex unspecified standardbred, equine 

HISTORY:  This yearling had bilateral scleral masses.

HISTOPATHOLOGIC DESCRIPTION:  32a:  Eye, bulbar conjunctiva:  There is focally extensive replacement of the bulbar conjunctiva with pigmented, cornified, stratified squamous epithelium and well differentiated pilosebaceous units in the subjacent dense collagenous stroma.  Within the connective tissue underlying the bulbar conjunctiva there are few perivascular lymphocytes and plasma cells and a lymphoid follicle.  Diffusely, there is mild congestion.  The epithelium is multifocally hyperplastic with moderate numbers of transmigrating lymphocytes and plasma cells within the epithelium.

MORPHOLOGIC DIAGNOSIS:  Eye, bulbar conjunctiva:  Dermoid, standardbred, equine.

Signalment (AFIP #267901):  Puppy, sex and breed unspecified

HISTORY:  None provided

HISTOPATHOLOGIC DESCRIPTION:  32b:  Eye, cornea:  Replacing 90% of the cornea is sparsely pigmented, cornified, stratified squamous epithelium overlying an irregular dermis that blends with the corneal substantia propria.  The dermis contains cystic follicles; nests of sebocytes; rare apocrine glands; a single hair shaft; and multifocal infiltrates of few neutrophils, lymphocytes, macrophages, and plasma cells.  The follicular cysts are up to 500 um in diameter and are lined by cornified, stratified squamous epithelium.  Luminal contents vary and include one or more of the following: parakeratotic concentrically laminated keratin, granular cellular debris with multifocal mineralization, individual keratinocytes, few neutrophils, and occasional necrotic debris.  Peripheral to the area of cutaneous differentiation there is a focus of mild corneal epithelial hyperplasia.  The deep corneal stroma is multifocally expanded by clear space (edema).

MORPHOLOGIC DIAGNOSIS:  Eye, cornea:  Dermoid, breed unspecified, canine.

CONDITION:  Dermoid

GENERAL DISCUSSION:

PATHOGENESIS:

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS:

TYPICAL LIGHT MICROSCOPIC FINDINGS:

DIFFERENTIAL DIAGNOSIS:

COMPARATIVE PATHOLOGY:

REFERENCES:

  1. Dubielzig RR, Ketring KL, McLellan GJ, Albert DM. Veterinary Ocular Pathology, a Comparative Review. Philadelphia, PA:Elsevier; 2010: 123,145,147.
  2. Gelmetti D, Bertoletti I, Giudice C. Bilateral complex microphthalmia with intraocular dermoid cyst in a neonate red deer (Cervus elephus). J Wildl Dis. 2010; 46(3):961-965.
  3. Labelle P. The eye. In: Zachary JF ed. Pathologic Basis of Veterinary Disease. 6th ed. St. Louis, MO: Elsevier; 2017:1297.
  4. Wilcock BP, Njaa BL. Special senses. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 1. 6th ed. St. Louis, MO: Elsevier Limited; 2016:421-422.


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