Bone destruction of orbital wall in idiopathic orbital inflammatory pseudotumor: does it always imply malignancy?

Aim: To assess the clinical presentations and outcomes of idiopathic orbital inflammatory pseudotumor (IOIP) patients with orbital wall bone destruction (OWBD) and to propose an expanded classification system that includes bone destruction.

Methods: The study retrospectively reviewed clinical presentations, imaging findings, treatment modalities, and outcomes of six patients diagnosed histopathologically with IOIP and OWBD at the Beijing Tongren Hospital, Capital Medical University between October 2018 and June 2021.

Results: Over two years, 6 (10%) of 60 IOIP patients at our hospital exhibited OWBD, but this may overrepresent severe cases. The cohort consisted of three men and three women, aged 17 to 60y (mean 35.5±16.1y). Presenting symptoms included proptosis, eyelid swelling, decreased visual acuity with pain, and palpable mass. Imaging revealed multiple anatomical structures involved with the medial wall being the most common site of bone destruction. Histopathological examination showed classic type in five patients and sclerosing type in one patient. All patients underwent surgical resection followed by methylprednisolone treatment. Follow-up (mean 30.3±3.1mo) indicated three patients had no recurrence, while others had varying degrees of symptom persistence or recurrence.

Conclusion: IOIP with bone destruction is a rare but significant subtype that mimics malignancy, leading to potential diagnostic and therapeutic challenges. Our findings suggest that complete surgical resection combined with adjunctive glucocorticoid therapy can yield favorable outcomes. However, larger-scale studies are needed to further optimize therapeutic approaches.