Analysis of the pathological composition ratio of orbital space-occupying lesions in 7 515 cases: single-center...

To analyze the pathological composition ratio of orbital space-occupying lesions in a large single-center cohort and to assess differences across age groups and decades.

A retrospective observational study.

A total of 7 515 patients with histopathologically confirmed orbital space-occupying lesions who underwent surgical excision at Zhongshan Ophthalmic Center from January 2000 to March 2021.

Demographic and histopathological data were reviewed. Lesions were classified by biological behavior (benign/borderline vs malignant), tissue origin, and age group (0-14, 15-59, and ≥60 years). Temporal trends were compared between 2000-2009 and 2010-2021.

Among 7 515 patients, 3 717 (49.5%) were male. Benign or borderline lesions comprised 78.0%, and malignant lesions comprised 22.0%, with mean ages of 36 and 49 years, respectively (p < 0.05). The leading histopathologic types were vasculogenic (22.3%), lymphoproliferative (16.4%), inflammatory (16.0%), and cystic (11.9%) lesions. Idiopathic orbital inflammatory pseudotumour was the most common benign entity, and mucosa-associated lymphoid tissue (MALT) lymphoma was the most frequent malignancy. Malignancy increases with age, reaching 43.6% in the elderly. Over 2 decades, vasculogenic lesions declined, while lymphoproliferative and malignant lesions rose.

The pathological spectrum of orbital space-occupying lesions in southern China is dominated by inflammatory and vascular lesions in younger patients and by lymphoproliferative malignancies in the elderly. Over the past two decades, vascular lesions have decreased, whereas lymphoproliferative and malignant lesions have become more prevalent, reflecting demographic aging and advances in diagnostic pathology. These findings provide updated epidemiologic evidence to guide the differential diagnosis and management of orbital tumours.