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Case ReportsAbstract
Uveal melanoma is the most common primary intraocular malignancy in adults and is molecularly distinct from cutaneous melanoma. Most cases harbor activating mutations in GNAQ or GNA11, particularly at codon Q209. The Q209L and Q209R variants are common, while Q209P is rare. We report a case of spindle cell uveal melanoma with a somatic GNAQ Q209P mutation in a 95-year-old woman.
The patient presented with a red, painful left eye and poor vision. MRI revealed a lobulated intraocular mass measuring 1.9 × 1.6 × 1.3 cm. Enucleation was performed. Grossly, a pigmented, solid tumor was present in the nasal quadrant of the globe, measuring 2.7 cm in basal diameter and 2.5 cm in thickness. Histologically, the tumor involved the ciliary body and choroid and was composed of >90% spindle cells. Focal perivascular and perineural invasion were noted. No direct scleral or extrascleral extension was identified, and all margins were negative. Immunohistochemistry showed diffuse positivity for S100 and SOX10, with negative staining for cytokeratin, SMA, and desmin. Molecular testing revealed a GNAQ c.626A>C (p.Q209P) mutation. BAP1 immunohistochemistry was not performed.
This case demonstrates a rare molecular variant in a histologically classic spindle cell uveal melanoma. Although Q209P is an activating mutation, its biological behavior is not well characterized. The patient’s advanced age and the tumor’s morphology suggest indolent behavior. This case adds to the limited literature on GNAQ Q209P and supports the utility of molecular profiling even in conventionally appearing melanomas.