Ocular pathology in melanomatous Sinclair miniature swine

Area of Science:

• Ophthalmology
• Dermatology
• Immunology

Background:

• Cutaneous melanoma in Sinclair swine can lead to ocular depigmentation.
• Ocular changes correlate with tumor regression and depigmentation.
• The precise mechanisms of these ocular changes require further investigation.

Purpose of the Study:

• To histologically examine ocular changes during cutaneous melanoma progression and regression in Sinclair swine.
• To correlate ocular depigmentation and uveitis with tumor behavior.
• To investigate the cellular and subcellular changes in the eye associated with melanoma regression.

Main Methods:

• Light and electron microscopy of swine eyes at various disease stages.
• Histological analysis of ocular tissues (cornea, ciliary body, iris, choroid).
• Correlation of ocular findings with clinical course of cutaneous tumors.

Main Results:

• Rapid cutaneous tumor regression was associated with acute uveitis, characterized by mononuclear cell infiltration.
• Ocular depigmentation occurred alongside skin depigmentation and tumor arrest.
• Melanin granules were observed within lysosomes of infiltrating mononuclear cells and later in fibrocytes.
• Band keratopathy (corneal calcification) was noted in late stages.

Conclusions:

• Ocular changes, including uveitis and depigmentation, are linked to the immune response during cutaneous melanoma regression in swine.
• The uptake of melanin by mononuclear cells suggests a role for these cells in the process.
• Further studies are needed to elucidate the specific cell-mediated immunity phenomena involved.