Tumor-Associated Retinal Pigmentation in Choroidal Melanoma

Area of Science:

• Ophthalmology
• Oncology
• Pathology

Background:

• Choroidal melanoma is a common primary intraocular malignancy.
• Accurate diagnosis and risk stratification are crucial for effective treatment.
• Novel clinical features can improve understanding of tumor biology.

Purpose of the Study:

• To identify and characterize a new clinical feature in choroidal melanoma, termed tumor-associated retinal pigmentation (TARP).
• To investigate the correlation between TARP and tumor biology, including histopathology and genetic markers.
• To assess the potential clinical implications of TARP in treatment planning.

Main Methods:

• Retrospective analysis of patients with choroidal melanoma exhibiting TARP.
• Detailed clinical, imaging (widefield funduscopy, FAF, OCT), and histopathological evaluation.
• Molecular genetic analysis (chromosome 3 status) and immunostaining (CD68, MelanA) of TARP.

Main Results:

• TARP was identified in 7.47% of choroidal melanoma cases.
• TARP lesions were hypofluorescent on FAF and appeared as hyperreflective foci on OCT.
• Immunostaining revealed TARP consists of CD68+ melanophages, not melanocytes.
• 90% of tumors with TARP showed monosomy 3, a marker of high metastatic risk.

Conclusions:

• TARP represents tumor-associated macrophages in choroidal melanoma, not melanocytes.
• The presence of TARP is associated with high-risk tumors, particularly those with monosomy 3.
• Recognizing TARP may allow for more precise radiation therapy planning, potentially reducing complications.