gms | German Medical Science

Benign fibrous histicytomas are common soft tissue tumors in adults. The most common ophthalmic localization is the orbit, but there are only rare case reports about histiocytomas at the corneoscleral limbus.

A 10-year-old boy presented with a yellowish lesion at his left eye which had been observed for the first time 6 months before and had increased in size since then. Examination showed a 6x4 mm measuring yellowish tumor with deep invasion of the sclera, the limbus and the corneal stroma. The lesion was incompletely removed by means of a deep lamellar resection. Histopathologic examination showed a subepithelial fibrous tumor containing numerous lipidfilled foamy cells, which could be identified immunohistochemically as histiocytes (CD 68 and Vimentin positive, S-100 negative). So the lesion was classified as a benign fibrous histiocytoma. Two years after surgery the tumor had enlarged and reached the optical axis (12,5 x 10 mm). A penetrating limbokeratoplasty with a graft of 12,5 mm diameter was performed including the optical axis. Microscopic examination confirmed a recurrent fibrous histiocytoma with deep infiltration of the corneal and scleral stroma. Six weeks postoperatively the graft showed a severe endothelial rejection with complete opacification despite systemic immunosuppression with mycophenolatmofetil. By an intensive topical and systemic steroid treatment the graft regained transparency (postoperative follow-up 4 months).

Fibrous histiocytomas can be classified histologically as benign, locally aggressive or malignant. The presented case shows a recurrent, locally aggressive variant that behaved like an infiltrative tumor despite its benign histological appearance. For that reason complete surgical resection is very important in these cases.