Case Study: July 2011

History

A 45 year old male presents with a retinal detachment and an ultrasound shows a posterior pole choroidal based mass.

The eye is enucleated.

The figures show low and high power images of the lesion in question.

Questions

What is the differential diagnosis of the lesion shown in the figures?
Which immunohistochemical profile could you request?
The lesion was positive for Factor 13a, focally for CD68, focally for smooth muscle actin and negative for CD34, HHV8, Melan A, cytokeratin and desmin. The proliferation fraction was around 2%. Which diagnosis is most favoured?

Click to show answers

Primary: melanoma, naevus, fibrous histiocytoma, cellular phase (non-lipidised) xanthogranuloma schwanomma, neurofibroma, leiomyoma, SFT.
Metastasis: Melanoma, SFT, DFSP.
A possible profile includes: S100, Melan-A, proliferation marker, CD68, Factor X111a, neurofilament, ASMA, desmin, CD34
Fibrous histiocytoma of the choroid, with exudative retinal detachment.

References

Benign fibrous histiocytoma of the choroid. Lam DS, Chow LT, Gandhi SR, Cheng MF, Chan DH, Tso MO Eye 1998, 12 ( Pt 2):208-11

Benign fibrous tumor of the choroid. Croxatto JO, D’Alessandro C, Lombardi A Archives of Ophthalmology 1989, 107(12):1793-6