JPC SYSTEMIC PATHOLOGY
SPECIAL SENSES SYSTEM
April 2018
S-M16

Signalment (JPC #2818284):  Dog

HISTORY:  None

HISTOPATHOLOGIC DESCRIPTION:  Eye:  Diffusely adhered to the anterior aspect of the iris is a 0.3 mm thick preiridal fibrovascular membrane composed of granulation tissue (plump fibroblasts with numerous small capillaries) admixed with foci of mature fibrous connective tissue, edema, fibrin and hemorrhage.  The iris is advanced rostrally and the preiridal fibrovascular membrane extends across the iridocorneal angle, obscuring the pectinate ligament and trabecular meshwork, causing adhesion between the iris and Descmet’s membrane (anterior synechia) and resulting in obstruction of the ciliary cleft.  The membrane in this region multifocally contains hemosiderin-laden macrophages, hemorrhage, fibrin, edema, and hematoidin crystals.  The iris margin deviates anteriorly through the pupil (ectropion uveae).  Extending from the ciliary body, covering the posterior lens capsule and to a lesser extent the anterior lens capsule, and adherent at the posterior aspect of the lens to the detached retina, is a variably thick band of fibrin admixed with erythrocytes, rare fibroblasts, lymphocytes, and plasma cells (cyclitic membrane).  Multifocally, there is disruption of lenticular fibers with replacement by eosinophilic, globular material (Morgagnian globules) and flocculent debris (cataractous change).  Diffusely, there is detachment of the retina, with multifocal traction bands and diffuse atrophy, degeneration and necrosis affecting all layers of the retina.  Multifocally, the retinal pigmented epithelium is hypertrophied. There is hemorrhage within posterior and anterior segments (hemophthalmos and hyphema) and the optic nerve.  Multifocally, the corneal epithelium is moderately hyperplastic.  The corneal stroma is expanded by numerous small caliber vessels lined by plump endothelium (neovascularization); infiltrated by aggregates of lymphocytes, plasma calls, and rare macrophages admixed with multifocal areas of hemorrhage; and corneal collagen fibers are diffusely mildly separated by clear space (edema).  Periocular musculature is separated and surrounded by abundant hemorrhage.

MORPHOLOGIC DIAGNOSIS: 

  1. Eye:  Preiridal and cyclitic fibrovascular membranes with organizing hemophthalmos, drainage angle occlusion, ectropion uveae, peripheral anterior synechia, cataractous change, and focally extensive retinal detachment and necrosis, breed not specified, canine.
  2. Eye, cornea: Keratitis, chronic, diffuse, mild, with vascularization.

CONDITION:  Pre-iridal fibrovascular membrane

GENERAL DISCUSSION:

PATHOGENESIS:

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS:

TYPICAL LIGHT MICROSCOPIC FINDINGS: 

COMPARATIVE PATHOLOGY:

 REFERENCES:

  1. Dubielzig RR, Ketring KL, McLellan GJ, Albert DM. Veterinary Ocular Pathology: a comparative review. Louis, MO: Saunders Elsevier; 2010:429, 436.
  2. Labelle P. The eye. In: Zachary JF, Pathologic basis of Veterinary Disease. 6th ed. St. Louis, MO: Mosby Inc; 2016:1279-1280. 
  3. Papaioannou NG, Dubielzig RR. Histopathological and immunohistochemical features of vitreoretinopathy in Shih Tzu dogs.  Comp. Pathol.  2013;148(2-3):230-235.
  4. Wilcock BP, Njaa BL. Special senses. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. 6th ed. Vol 1. St. Louis, MO: Elsevier Inc; 2016:447-448.


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