Mukoepidermoides Karzinom der epibulbären Bindehaut mit diffuser intraokulärer Epithelinvasion

 

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Summary

Background Mucoepidermoid carcinoma affects primarily the major and minor salivary glands and is uncommon in the conjunctiva. When it affects the conjunctiva, however, this neoplasm displays a higher capacity for intraocular/orbital invasion and earlier (i.e. less than six months), extensive recurrence than squamous cell carcinoma which clinically closely resembles mucoepidermoid carcinoma and is more common. Mucoepidermoid carcinoma of the conjunctiva has the potential to invade epithelium extensively without altering the clinical appearence of the conjunctiva, or even the skin.

Unfortunately, the subtle histologic features that distinguish squamous cell from mucoepidermoid carcinoma can be easily overlooked. Cardinal among these features is the presence of mucus-secreting cells within a matrix of epidermoid cells in mucoepidermoid carcinoma. Special techniques (mucicarmine, alcian blue) stain mucin in extracellular cystoid spaces and intracytoplasmic vacuoles. Sometimes mucin may only be found in the recurrent intraocular component of the tumor, with the primary epibulbar lesion presenting only the histologic features of squamous cell carcinoma.

Patient A 55-year-old man was treated twice with local excision and crycoagulation for a recurrent limbal mass of the left eye. The original histologic diagnosis was squamous cell carcinoma. Three months after the last recurrence the globe was enucleated because of a spontaneous perforation at the corneoscleral limbus with iris prolapse. Histologic examination, including PAS and mucicarmine stains, revealed a mucoepidermoid carcinoma of the epibulbar conjunctiva with infiltration of the cornea, sclera, iris and ciliary body.

Conclusions Examination of specially stained sections (e.g. with mucicarmine) should be routinely performed for those conjunctival neoplasms that contain a squamous component. Aggressive surgical management, such as early enucleation including normal appearing tissue next to the globe, should be considered for treatment of primary mucoepidermoid carcinoma to avoid later exenteration or metastasis.