Which of the following is not of prognostic significance to choroidal melanoma ?
**Core Concept**
Choroidal melanoma is a type of eye cancer that originates from the pigment-producing cells of the choroid, a layer of tissue between the sclera and retina. The prognosis of choroidal melanoma is influenced by various factors, including tumor size, location, and genetic characteristics.
**Why the Correct Answer is Right**
Tumor thickness, specifically the largest basal diameter, is a well-established prognostic factor for choroidal melanoma. The thicker the tumor, the higher the risk of metastasis and mortality. In contrast, the correct answer is not a significant prognostic factor for choroidal melanoma.
**Why Each Wrong Option is Incorrect**
**Option A:** Tumor thickness is a well-established prognostic factor for choroidal melanoma, with thicker tumors associated with a higher risk of metastasis and mortality.
**Option B:** The largest basal diameter is a key component of tumor thickness and is used to determine prognosis in choroidal melanoma.
**Option C:** The correct answer is not of prognostic significance to choroidal melanoma, as it is not a well-established risk factor for metastasis or mortality.
**Clinical Pearl / High-Yield Fact**
When evaluating choroidal melanoma, it's essential to consider the tumor's largest basal diameter, as it is a critical determinant of prognosis.
**Correct Answer:** D