This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Uveal Tract, Subject name: Ophthalmology
Intractable secondary glaucoma is seen in: 
Select and explain. 
A. Diffuse iris melanoma, B. Nodular iris melanoma, C. Melanocytic deposits in anterior part of iris, D. Melanocyte proliferation in posterior uveal tissue
A: Diffuse iris melanoma
Answer: A: Diffuse iris melanoma 
Explanation: Ans. (a) Diffuse iris melanomaRef: Surgical Pathology of Head & Neck p. 1935Intractable secondary glaucoma may also occur in cases of blunt trauma due to anteriorly dislocated lens setting caught in the pupil.Iris melanoma(malignant neo plasms that arise from neuroectodermal melanocytes with in the Iris)Circumscribed/nodular iris melanoma* Present as pigmented spot on the iris* These tumors are usually localized, well circumscribed and nodular* These tumors usually tend to involve only a limited segment of the angle circumference and hence glaucoma is less common and usually treatableDiffuse iris melanoma* Present as a unilateral dark iris (hyperchromic heterochromia) Q* These tumors show a flat and diffuse infiltration pattern of growth* The infiltration invades the intertrabecular spaces and plugs the drainage mechanism, resulting in an intractable secondary glaucoma