Background: We report on a case of primary orbital Merkel cell carcinoma (MCC).
Case: An 87-year-old man presented with swelling of the left bulbar conjunctiva. Slit-lamp examination revealed a reddish temporal bulbar conjunctival mass in his left eye. A fluorescein eye stain test revealed a central epithelial defect at the left cornea. The eyelid was normal. Computed tomography and magnetic resonance imaging revealed a highly integrated lesion (23×18×17 mm) in the left temporal orbit. Metastasis to regional lymph nodes or other tissues was not detected. Pathological analysis of a tumor biopsy specimen revealed cells showing obvious signs of malignancy positive for epithelial and neuroendocrine markers, but negative for malignant melanoma and lymphoma markers. On the basis of immunohistological staining and histopathological examination, we diagnosed the tumor as MCC. The mass was resected using an approach through the temporal bulbar conjunctiva. The patient was treated with postoperative radiotherapy, but metastasis to auricular lymph node, accessory nerve lymph node and cervical lymph node was detected 3 months later. Although the patient underwent additional radiotherapy, he died 17 months after the initial visit because of multiple distant metastases.
Conclusions: Our experience with this case of primary orbital MCC suggests that metastasis should be considered as possibility for this rare, aggressive carcinoma.
Nippon Ganka Gakkai Zasshi (J Jpn Ophthalmol Soc) 121:930-935, 2017.