Fibrous Histiocytoma of the Lacrimal Sac in an 11-Year-Old Male.

Fibrous histiocytoma is a soft tissue tumor with cells resembling both fibroblasts and histiocytes. Occasionally in the orbit, they rarely arise in the lacrimal sac. Similar to prior cases described, the patient presented with symptoms of epiphora and a slowly enlarging mass inferior to the right medial canthus. Imaging demonstrated a circumscribed 1.2 cm × 1.1 cm × 1.1 cm mass within the lacrimal sac without surrounding bony destruction. Grossly, the tumor appeared homogenous and rubbery. Pathologic study results from the case demonstrated zones of hypercellularity and hypocellularity with a fibrous appearance, admixed with spindle cells and collections of foamy histiocytes. A diagnosis of benign fibrous histiocytoma was rendered, with the patient experiencing a complete resolution of symptoms at subsequent follow up. To the authors' knowledge, this is the first reported solitary case report of a fibrous histiocytoma of the lacrimal sac in a pediatric patient.