Expression of cell cycle related proteins in a rapidly growing uveal malignant melanoma

Purpose: To report the clinical and immunohistochemical findings of a rapidly growing uveal melanoma. Methods: A 71-year-old Japanese woman was diagnosed with a juxtapapillary uveal melanoma by clinical examination. The tumor grew rapidly with a 31.5-day doubling time. An enucleation was performed, and immunohistochemical examination for cell cycle proteins was performed in addition to routine histopathologic examination. Results: The melanoma cells were classified as spindle B-cells. The tumor cells were positive for HMB-45 protein, but negative for S-100 protein. The tumor showed immunohistochemical staining for p16 and Bcl-2, although p53 was not detected. Immunoreactivity for pRb was found in normal retinal and choroidal cells but not in the tumor cells. Conclusion: This report describes a unique case of rapidly growing uveal melanoma, which showed low histopathologic grade while the cell cycle protein immunohistochemical profile suggests a more aggressive phenotype. The evaluation of cell cycle proteins may be useful adjunctive method to enhance the understanding of uveal melanoma growth patterns.