Thymic Carcinoma Metastatic to the Orbit

Purpose To report a case of small cell carcinoma of the thymus metastatic to the orbit. Methods At age 37 years, a man who had been previously diagnosed and treated for small cell carcinoma of the thymus was initially examined for vertical diplopia and left proptosis. Computed tomographic scan disclosed a soft tissue mass in the superior aspect of the left orbit. A fine-needle aspiration biopsy of the mass was performed and submitted for cytopathologic examination. Result The cytopathology and immunopathology disclosed malignant cells consistent with metastatic small cell thymic carcinoma. Conclusion This is the first reported case of a primary thymus gland tumor metastatic to the orbit.