JPC SYSTEMIC PATHOLOGY
SPECIAL SENSES
April 2018
S-N07

Signalment (JPC# 4066796): 12-year-old intact domestic shorthair cat.

HISTORY: This cat had corneal perforation of unknown duration, suspected cataracts and suspected anterior lens luxation of the right eye (OD), and the eye was enucleated. Grossly, the right globe was 1.9 cm in nasolateral diameter, and had a white-tan, raised mass at 3-6 o'clock. On cut section, the mass was firm to slightly gritty and obscured the ciliary body and a portion of the iris. The lens was opaque and slightly irregular. The retina was detached, and the peripheral iris was irregular segmentally.

HISTOPATHOLOGIC DESCRIPTION: Eye, globe:  Within the anterior chamber, extending from the lens epithelium, adherent to the fragmented lens capsule, infiltrating the choroid, and incorporating the detached atrophic retina is a well-demarcated, infiltrative, moderately cellular, unencapsulated, multilobulated neoplasm composed of neoplastic chondrocytes evenly dispersed within a light blue partially mineralized chondroid matrix.  In the center of the neoplastic lobules, chondrocytes are within lacunae, have a moderate amount of clear to highly vesiculated cytoplasm, and a round pink nucleus with a prominent nucleolus.  At the periphery of neoplastic lobules, neoplastic cells are more spindled to stellate with a moderate amount of vesicular amphophilic cytoplasm, an ovoid to elongate nucleus with finely stippled chromatin, and 0-1 variably distinct nucleoli.  Mitotic figures are predominantly within the peripheral spindle cell population and average 3 per 10 40x HPF (2.37mm2). The cartilaginous matrix contains foci of mineralization.  The neoplasm adheres to a break in the lens capsule and extends partially circumferentially around the lens.  Lens fibers multifocally undergo marked subcapsular spindle cell metaplasia, mild subcapsular cartilaginous metaplasia, and mineralization.  There is a multifocal thin prelenticular fibrous membrane that is up to 250um thick and extends around the lens and extends to the ciliary body (cyclitic membrane).  The neoplasm distorts the ciliary body and is unilaterally confluent with the iris which is elevated and adhered to the corneal endothelium (anterior synechia) by a membrane of loosely arranged collagen (pre-iridal fibrovascular membrane) and moderate numbers of lymphocytes, plasma cells, and pigment laden macrophages.  The neoplasm extends under (external to) the ciliary body and into the choroid and along a detached segment of retina; there is abundant clear space separating layers of the choroid (edema).  The retina displays marked atrophy of all layers, most prominently of the inner retinal layers with cystic degeneration of the outer retinal layers.  There is a small amount of subretinal proteinaceous exudate and hypertrophy of the retinal pigmented epithelium.  The anterior aspect of the iris distant to the neoplasm is covered by a thin fibrovascular membrane (pre-iridal fibrovascular membrane) that extends across and occludes the iridocorneal angle, and onto the corneal endothelium.  This fibrovascular membrane contains moderate numbers of lymphocytes and fewer macrophages and plasma cells that infiltrate the edematous anterior aspect of the iris.  There is a central break in Descemet’s membrane with associated corneal thickening due to stromal infiltration with numerous lymphocytes, plasma cells, fewer macrophages, and melanin-laden macrophages, and ingrowth of small caliber blood vessels (neovascularization).  There is diffuse vacuolation and hypertrophy of the corneal endothelium and mild hyperplasia of the corneal epithelium.

MORPHOLOGIC DIAGNOSIS:

  1. Eye, globe: Chondrosarcoma (post-traumatic ocular sarcoma).
  2. Eye, lens: Lenticular rupture with subcapsular fibrous and chondroid metaplasia.
  3. Eye, cornea: Keratitis, lymphoplasmacytic and histiocytic, focally extensive, chronic, moderate, with Descemet’s membrane rupture.

ETIOLOGIC DIAGNOSIS/CONDITION: Feline post-traumatic ocular sarcoma (FPTOS); primary ocular sarcoma

GENERAL DISCUSSION:

PATHOGENESIS:

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS:

TYPICAL LIGHT MICROSCOPIC FINDINGS:

ADDITIONAL DIAGNOSTICS:

DIFFERENTIAL DIAGNOSIS:

COMPARATIVE PATHOLOGY:

References:

  1. Beckwith-Cohen B, Teixeira LBC, Dubielzig RR. Presumed primary intraocular chondrosarcoma in cats. J Vet Diag Invest. 2014; 26(5):664-668.
  2. Dubielzig RR, Everitt J, Shadduck JA, Albert DM. Clinical and morphologic features of post-traumatic ocular sarcomas in cats. Vet Pathol. 1990; 27(1):62-65.
  3. Dubielzig RR. Non-surgical trauma.  In: Dubielzig RR, Ketring KL, McLellan GJ, Albert DM. Veterinary Ocular Pathology, a Comparative Review. Philadelphia, PA:Elsevier; 2010:81-114.
  4. Labelle P. The eye. In: Zachary JF, Pathologic Basis of Veterinary Disease. 6th ed. St. Louis, MO: Mosby Inc; 2016:1303-1304, 1306. 
  5. Morrison WB, Starr RM. Vaccine-associated feline sarcomas. J Am Vet Med Assoc. 2001; 218:697-702.
  6. McPherson L, Newman SJ, McLean N, McCain S, et al. Intraocular sarcomas in two rabbits. J Vet Diagn Invest. 2009(4); 21:547-551.
  7. Lin H, Ouyang H, Zhu J, Huang S, et al. Lens regeneration using endogenous stem cells with gain of visual function. Nature. 2016; 531:323-328.
  8. 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; 2016:478-488.
  9. Zeiss CJ, Johnson EM, Dubielzig RR. Feline intraocular tumors may arise from transformation of lens epithelium. Vet Pathol. 2003; 40(4):355-362.


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