Sebaceous adenocarcinoma of meibomian gland origin with targetoid intra-nuclear inclusions.

Neoplastic proliferation of the meibomian glands is most often characterized by a tarsal tumor of the eyelid conjunctiva, having the clinical appearance of a chalazion. As such, the tumor is frequently not recognized as a neoplasm and is treated conservatively as an inflammatory lesion. A protracted clinical course combined with repeated surgical excisions typify this slow-growing tumor of sebaceous gland cells. In addition to the usual features of polygonal cell shape, abundant cytoplasm, and numerous fat vacuoles, we describe the presence of a peculiar nuclear inclusion seen only in the parenchymal cells of this tumor, and having the appearance of concentric layers of electron-dense material surrounding an opaque electron lucent core.