Intratarsal Keratinous Cyst – An Emerging Entity
A 57-year-old Caucasian female with a history of bilateral upper and lower eyelid blepharoplasty presented to the clinic with a complaint of a recurrent left upper eyelid lesion that had been excised two years prior. Initially, the lesion had been present for about a year, had developed surrounding erythema, and had burst a few times, producing a white discharge. At that time the excised lesion had been identified as a benign epithelial cyst in the tarsus by pathology. After excision, the patient had relief until three months prior to presentation, when the cyst recurred, causing foreign body sensation in the left eye with blinking. Examination revealed pinhole visual acuity of 20/20 bilaterally. External examination was remarkable for acne rosacea of the upper and lower eyelids and mid face bilaterally as well as bilateral Meibomian gland dysfunction. On eversion of the left upper eyelid, there was a small, white, well-circumscribed, nodular lesion in the tarsus with inflammation of the surrounding conjunctiva (fig. ). The lesion was removed using a full-thickness excision of the conjunctival tarsus, and the defect was covered with an amniotic membrane patch graft.\nHistopathologic examination revealed an intratarsal keratinous cyst lined by stratified squamous epithelium with a smooth luminal aspect, containing cord-like keratin lamellae. The epithelium lacked goblet cells and sebaceous cells; however, there were few clear cells present (fig. ). Immunohistochemistry revealed expression of pancytokeratin (AE1/AE3) in the cyst cuticle and lining (fig. ). The expression of AE1/AE3 was nonspecific and also seen in adjacent Meibomian gland ducts (data not shown). In addition, there was expression of cytokeratin (CK) 903 in the epithelium, cuticle, and contents, and expression of CK 5/6 in the cyst lining and contents, but not cuticle (fig. ; table ). The sloughed keratinous material within the cyst strongly expressed CEA (fig. ), but we did not identify staining with this antibody in the normal Meibomian gland. The cyst was immunonegative for p16, CK 7, CK 18, CK 20, and EMA (table ). The Ki67 expression index was very low.