It accounts for only 3%-10% of all uveal melanomas.
INHERITANCE PATTERN
VISUAL ACUITY
It may be affected due to cataracts and irregular astigmatism due to lens tilt.
IRIS AND PUPIL
It is seen as an elevated, pigmented lesion that may have abnormal iris vessels.
Morphology of Iris Melanoma
Circumscribed melanomas – they are nodular and are typically yellow, tan, or brown in color with a flat or rounded anterior contour. Surface variability of pigmentation is a sign of malignant histology—lower risk for metastasis.
Diffuse melanomas present as unilateral dark iris (acquired heterochromia) without focal thickening. They often tend to have epitheloid cell type, and distant metastasis occurs in 13% of patients with diffuse iris melanomas.
Tapioca Iris Melanoma – it’s a variant of melanoma having multiple amelanotic nodules on th
Correctopia
Ectropion Uveae (May also be associated with Iris Naevus).
LENS
Cataract – usually sectoral
Anterior chamber
The reaction is associated with tumor growth; the patient may be misdiagnosed as having chronic anterior uveitis and pigment dispersion syndrome.
Hyphema
POSTERIOR SEGMENT
Perform Indirect examination with scleral depression to differentiate between iris cysts, primary iris tumors, and primary ciliary body melanomas.
IOP
Glaucoma – d/t invasion of malignant cells into TM (seeding), decreased aqueous outflow due to pigment-ingesting macrophages blocking the angle, angle closure, and neovascularization.
ANCILLARY TESTING
Gonioscopy
ASOCT – it is superior to UBM for iris melanomas.
UBM – Lion’s paw appearance
Photo documentation is a must.
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