TREATMENT AND HISTOPATHOLOGY OF A CONGENITAL VITREOUS CYST

Objective: This study aimed to evaluate the treatment efficacy of a co ngenital vitreous cyst and to examine the cyst histopathologically to determine its cellular makeup and possible origin. Study Design: The s tudy design was a case report, including a clinicopathologic correlati on. Intervention: A 35-year-old woman with a known vitreous cyst since childhood became increasingly troubled by its symptoms. The cyst was treated initially with argon laser photocoagulation, Vitrectomy subseq uently was performed because the deflated cyst remained near the visua l axis. Histopathologic studies included light and electron microscopy ; immunocytochemistry for actin and glial fibrillary acidic protein (G FAP); and enzyme histochemistry for carbonic anhydrase (CA). Results: The cyst was composed of a single layer of heavily pigmented cells wit h a thick basement membrane along the internal borders of the cells. U ltrastructurally, the cells were connected with tight junctions, had m icrovillous processes at their apices, and contained numerous large me lanosomes in various stages of maturity, including premelanosomes. Imm unochemistry showed the cells were positive for actin but negative for GFAP, Enzyme histochemical staining for CA also was strongly positive . Conclusions: The confinement of this cyst to the region of Cloquet's canal, the presence of a Mittendorf's dot, the cyst's existence for m any years, and the finding of pigment epithelial-type cells having imm ature melanosomes (a feature not seen after birth in normal pigment ep ithelium) lead the authors to believe that this cyst was a congenital remnant of the primary hyaloidal system. Because pigmented cells are n ot normally present in this part of the eye, the cyst was a choristoma of the primary hyaloidal system.