Mitochondrial DNA mutations in oncocytic adnexal lacrimal glands of the conjunctiva.

O ncocytic neoplasms are characterized by a marked mitochondrial hyperplasia. They are of epithelial derivation and usually occur in endocrine and exocrine organs such as the thyroid, parathyroids, kidney, pituitary, and salivary glands. Oncocytic lesions of the ophthalmic regions have been reported, especially as oncocytic adenomas of the caruncle. Similar lesions occur rarely in the adnexal lacrimal glands of the conjunctiva. Truncating mitochondrial DNA (mtDNA) mutations in respiratory complex I (CI) subunits have been suggested to be the genetic hallmark of the oncocytic phenotype. The occurrence of such genetic lesions strongly impairs cell respiration and contributes to maintaining the tumor in a low-proliferating, benign state. We describe an oncocytoma of the adnexal lacrimal glands of the conjunctiva harboring mtDNA mutations that cause CI disassembly and associate with a low proliferation index.