[Histopathologic classification of 1921 orbital tumors]

The retrospective study is undertaken to determine the histopathologic types of space-occupying lesions of the orbit in 1921 cases examined between 1953-1992 at the Eye Pathology Laboratory of Shanghai Medical University.

The authors reviewed old diagnostic pathologic slides on file including HE stain as well as special stains, if available, for all the indeterminate cases. Newly prepared immunohistochemical stains are made for the controversial cases to help diagnosis. Some slides are discussed and diagnosed by Pathology Slide Meeting of the Shanghai Surgical Pathology Society. Cases with diagnosis not agreed upon by the pathology meeting are excluded from this study.

The 5 leading malignant orbital tumors are malignant lacrimal gland tumors (138 cases, 32%), malignant lacrimal sac tumors (112 cases, 26%), rhabdomyosarcomas (65 cases, 15%), lymphosarcomas (56 cases, 13%), and malignant hemangiopericytomas (31 cases, 7%). The 5 leading benign orbital tumors are cavernous hemangionas (411 cases, 36%), dermoid cysts (152 cases, 13%), benign mixed tumors (150 cases, 13%), inflammatory pseudotumosr (129 cases, 11%), and schwannomas (92 cases, 8%). Rare tumors of the orbit include alveolar soft tissue sarcoma, chondrosarcoma, mesenchymal chondrosarcoma, synovial sarcoma, giant cell tumor, granular myoblastoma, yolk sac tumor, and retinal anlage tumor.

This study, in agreement with other reports of the statics study of the orbital tumors demonstrates the prevalence of hemangiomas, lacrimal gland tumors and lymphoid pseudo-tumors to be the common space-occupying lesions in the orbit. Some rare tumors are discussed.