Purpose: Solitary fibrous tumor is a rare spindle cell tumor arising in the pleura. We report two cases of this tumor occurring in the lacrimal sac.
Methods: A 23-year-old man and a 34-year-old woman presented with a medial canthal mass. They underwent surgical excision of their tumors.
Results: Solitary fibrous tumors were diagnosed by light microscopy, immunohistochemical study, and electron microscopy. Immunohistochemical staining showed that tumor cells were reactive with vimentin and CD34 and demonstrated no smooth muscle or neural differentiation (nonreactive with desmin and S-100 protein).
Conclusions: The findings indicate that solitary fibrous tumor can occur in the lacrimal sac and may recur locally if it is removed incompletely. To our knowledge, these are the first reported cases of solitary fibrous tumors occurring in the lacrimal sac.