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.
Key words
conjunctiva - diffuse epithelial ingrowth - enucleation - mucoepidermoid carcinoma
- globe perforation - mucicarmine stain
Schlüsselwörter
Bulbusperforation - Konjunktiva - Diffuse Epithelinvasion - Enukleation - Mukoepidermoides
Karzinom - Mucicarminfarbung
