Which of the following is NOT of prognostic significance in choroidal melanoma?

Presence of retinal detachment is not a prognostic feature of choroidal melanoma. There are clinical and histopathological prognostic factors which determine survival in patients with choroidal melanoma. Clinical prognostic factors indicating poor prognosis includes: large basal tumor diameter, anteriorly situated tumor, advanced age of patient, extraocular extension, male gender and ring melanoma. Histological poor prognostic factors includes: presence of predominant epithelioid cells in tumor, lymphocytic infiltration, presence of mitotic activity, and presence of vascular loops. Ref: Postgraduate Ophthalmology, Volume 1 edited by Zia Chaudhuri, page 1441.