Collagenous Fibroma With Metaplastic Ossification in the Periocular Region.

Collagenous fibroma is a rare benign soft-tissue tumor, and involvement of the periocular region is exceptionally uncommon. Metaplastic ossification within this tumor has rarely been reported and may further obscure its clinical and radiologic interpretation. The authors describe the case of a 49-year-old woman with a small, firm periocular mass in the lateral eyebrow region. Magnetic resonance imaging demonstrated a well-circumscribed lesion with low signal intensity, raising concerns for other fibrous or osseous tumors. Histopathologic examination revealed a hypocellular, collagen-rich stroma containing sparse spindle-to-stellate fibroblastic cells and discrete islands of mature lamellar bone, consistent with a collagenous fibroma with metaplastic ossification. Complete local excision was curative, with no evidence of recurrence. This case emphasizes that periocular collagenous fibroma with ossification, although benign, can mimic more aggressive lesions and should be recognized to avoid diagnostic confusion and unnecessary aggressive management of periocular lesions.