Frederick A Jakobiec1, John Nguyen, Kenneth Mandell, Aaron Fay. 1. Department of Ophthalmology, the David G. Cogan Ophthalmic Pathology Laboratory, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts 02114, USA. Fred_Jakobiec@meei.harvard.edu
Abstract
PURPOSE: To describe the findings observed in a congenital ectopic tooth of the lower inner eyelid and explain its origin. DESIGN: Retrospective and interventional clinicopathologic study. METHODS: Histopathologic evaluation of sequentially excised specimens over 4 years and radiographic study of any associated dental abnormalities, compared with critical reevaluation of similar reported cases in the literature. RESULTS: The ectopic eyelid tooth clinically created a dome-shaped mass and microscopically displayed advanced cytodifferentiation but incomplete morphogenesis with clearly identifiable ameloblasts, enamel, odontoblasts, and dentin, surrounded by an intact dental sac. Swollen oral mucosal epithelium with associated sebaceous Fordyce nodules, residual ciliated odontogenic epithelium, embryonic epithelial rests, and accessory mucinous and sero-mucinous accessory salivary glands were discovered in place of normal conjunctiva. The tarsus with meibomian glands was absent but islands of cartilage were present. CONCLUSIONS: Because of the variety of the ectopic tissues that were exhibited, a causative displacement of oral embryonic epithelium with extensive differentiating potentialities is posited. Two previously reported palpebral dental choristomas also had identical locations in the inferomedial eyelid. This is the site where the phakomatous choristoma may be encountered, but this unencapsulated mass creates an eyelid thickening without a globoid configuration and infiltrates the inferior orbit. After a careful re-appraisal of published reports of orbital cysts bearing a tooth that were formerly diagnosed as "teratomas," we have concluded that they developed from similar embryonic oral (buccal) epithelial displacements rather than from aberrant germ cells, based on the cysts' linings and the associated accessory salivary glands in their walls. This view is further supported by the absence of heterologous teratomatous elements of endodermal or neuroectodermal derivation. A clinical and surgical approach to management and a new diagnostic schema for odontogenic choristomas are proposed.
PURPOSE: To describe the findings observed in a congenital ectopic tooth of the lower inner eyelid and explain its origin. DESIGN: Retrospective and interventional clinicopathologic study. METHODS: Histopathologic evaluation of sequentially excised specimens over 4 years and radiographic study of any associated dental abnormalities, compared with critical reevaluation of similar reported cases in the literature. RESULTS: The ectopic eyelid tooth clinically created a dome-shaped mass and microscopically displayed advanced cytodifferentiation but incomplete morphogenesis with clearly identifiable ameloblasts, enamel, odontoblasts, and dentin, surrounded by an intact dental sac. Swollen oral mucosal epithelium with associated sebaceous Fordyce nodules, residual ciliated odontogenic epithelium, embryonic epithelial rests, and accessory mucinous and sero-mucinous accessory salivary glands were discovered in place of normal conjunctiva. The tarsus with meibomian glands was absent but islands of cartilage were present. CONCLUSIONS: Because of the variety of the ectopic tissues that were exhibited, a causative displacement of oral embryonic epithelium with extensive differentiating potentialities is posited. Two previously reported palpebral dental choristomas also had identical locations in the inferomedial eyelid. This is the site where the phakomatous choristoma may be encountered, but this unencapsulated mass creates an eyelid thickening without a globoid configuration and infiltrates the inferior orbit. After a careful re-appraisal of published reports of orbital cysts bearing a tooth that were formerly diagnosed as "teratomas," we have concluded that they developed from similar embryonic oral (buccal) epithelial displacements rather than from aberrant germ cells, based on the cysts' linings and the associated accessory salivary glands in their walls. This view is further supported by the absence of heterologous teratomatous elements of endodermal or neuroectodermal derivation. A clinical and surgical approach to management and a new diagnostic schema for odontogenic choristomas are proposed.