STAT6-positive solitary fibrous tumour of the lacrimal gland with floret-type giant cells: a rare case report

Abstract Background Solitary fibrous tumours (SFTs) are rare fibroblastic neoplasms, and involvement of the lacrimal gland is uncommon. Case presentation A non-smoking Egyptian man aged 52 years presented with a five-month history of enlarging left lacrimal swelling, proptosis, and mildly reduced left visual acuity (6/9 at presentation). Non-contrast orbital computed tomography showed a well-defined 9 × 12 mm lesion without bone erosion or local invasion. Complete surgical excision was performed. Histopathological examination demonstrated a patternless spindle-cell tumour with staghorn vasculature, low mitotic activity, and floret-type multinucleated giant cells, without necrosis, lymphovascular invasion, or perineural invasion. The tumour cells expressed CD34, CD99, BCL2, and diffuse nuclear STAT6, supporting the diagnosis of SFT. Surgical margins were negative. At three-month follow-up, visual function had fully recovered, with no diplopia. Conclusions This report adds a small, completely excised, low-risk example of lacrimal gland SFT in which floret-type giant-cell morphology is documented alongside diffuse nuclear STAT6 staining. Recognition of this pattern is important because it may overlap with other giant-cell-rich spindle-cell lesions. Complete excision with negative margins and risk-adapted long-term surveillance remain appropriate management principles.