Experts of the Filatov Institute (State Institution “Filatov Institute of Eye Diseases and Tissue Therapy of the National Academy of Medical Sciences of Ukraine”) have presented the results of a study describing a unique clinicopathological case of a rare form of orbital schwannoma, characterized by an unusual clinical presentation and significant challenges in histomorphological diagnosis.

Schwannoma (neurilemmoma) is a relatively rare orbital tumor, accounting for approximately 1% of all orbital tumors. In most cases, the neoplasm has a characteristic appearance and does not present significant difficulties in morphological verification. However, certain cystic forms may significantly complicate diagnostic assessment.

The study analyzed two surgical specimens obtained during 2025. At the time of first presentation, a cystic lesion was detected in the lateral orbital wall. After its excision, the lesion was predominantly composed of a yellowish-gray mucoid substance.. Histological examination did not allow to establish of the lesion’s nature due to the absence of preserved tumor tissue elements.

Eight months later, the patient re-presented with recurrence of the lesion in the same anatomical zone. During the repeat examination revealed a cystic formation up to 2.5 cm in diameter with a thin fibrotic wall and a cavity filled with a gelatinous mass.

Despite significant difficulties in histological diagnosis, careful examination of serial sections allowed pathomorphologists to identify residual tumor tissue with characteristic palisading patterns and Verocay bodies, which allowed for a definitive diagnosis of neurilemmoma (schwannoma).

The findings indicate that such variants of schwannoma may remain unverified and be misclassified as orbital cysts of unclear etiology. Underestimation of the macroscopic features of the lesion may lead to diagnostic errors, particularly in cases of significant tumor tissue degeneration.

This study has important practical implications for ophthalmic oncology and pathological anatomy, as it expands the understanding of rare orbital tumor forms and improves diagnostic accuracy.

Authors:
• Oleksandr V. Artiomov, MD, PhD — Senior Pathologist, Head of the Pathology Laboratory, Filatov Institute
• Iryna O. Safronenkova, MD, DSc — Senior Researcher, Department of Ophthalmo-Oncology, Ophthalmologist of Highest Category, Filatov Institute