Figure 2. Magnetic resonance imaging of the left orbit showing a well-encapsulated GW-572016 cyst, overlying the medial globe without surrounding erosion; the medial rectus muscle appears to insert at the posterior pole of the cyst. Treatment Planned strabismus repair targeted the recovery and advancement of the ��apparently slipped�� medial rectus muscle, recession of the lateral Inhibitors,Modulators,Libraries rectus muscle and excision of the mass in toto, if possible. Intraoperative unroofing of a superficial layer of conjunctiva over the mass revealed a chocolate-colored cyst filled with sero-sanguninous fluid, with strands of flaccid extraocular muscle or pseudo-tendon straddling its surface (Figure 3). The color of the fluid was attributed to prior hemorrhage.

Although excision in one piece proved technically challenging, an excisional biopsy of one large Inhibitors,Modulators,Libraries section of the mass included up to 10 mm of the flaccid medial rectus fibers. A gentle hand-over-hand technique was required to reach the posterior extension of the cyst, enabling recovery of the medial rectus muscle, well posterior to the equator and still attached to the posterior surface of the remaining wall of the cyst via a thin thread of muscle fiber. The body of the medial rectus muscle was recovered, advanced, and reattached to the anatomical insertion with Inhibitors,Modulators,Libraries an adjustable-suture technique after all visible remaining tissue from the cyst was surgically excised. The lateral rectus muscle was recessed on an adjustable suture. In the recovery room, the muscles were adjusted to a resultant esotropia of <10 PD at distance and at near.

Mild limitation of adduction remained. Three months later, the patient��s sensorimotor examination demonstrated an exotropia of 8 PD at distance and 8�C10 PD at near, with ?1 limitation of adduction and ?1.5 limitation of abduction. There has been no Inhibitors,Modulators,Libraries recurrence of the mass over a one-year follow-up period, and alignment has been stable. Figure 3. Intraoperative appearance of the chocolate-colored cyst filled with serosanguninous fluid, with strands of flaccid extraocular muscle straddling its surface. Differential Diagnosis The differential diagnosis of a non-invasive cystic mass in the medial orbit includes a variety of simple epithelial cyst, dermoid cyst, cystic teratoma, neural cyst, mucocele, encephalocele, lymphangioma, inflammatory cyst, parasitic cyst, hematic cyst, and cystic tumors.

1 Diagnosis and Discussion Histopathological examination of the excised lesion showed a cystic structure with a thin wall lined by a double layer of non-keratinizing cuboidal epithelium. The cyst content was acellular, proteinaceous material. No skin appendages or goblet cells were identified, and the epithelial cells did not have cilia. In some areas the cells appeared Inhibitors,Modulators,Libraries to have Cilengitide luminal projections, suggestive of apical apocrine snouts (Figure 4A). Immunohistochemistry for pan keratin highlighted the epithelial lining (Figure 4B).