A 70-year-old woman presented to the ophthalmology department with a two-month history of a progressively enlarging mass on her left upper eyelid. She denied visual impairment, ocular redness, or pain. Her medical history included a prior diagnosis of meibomian gland inflammation, for which she received local anti-inflammatory treatment; however, her symptoms worsened following intervention. On examination, best-corrected visual acuity was 0.7 (non-improvable) in the right eye and 1.0 in the left eye. Intraocular pressures were within normal limits (20 mmHg OD, 21 mmHg OS). The left upper eyelid exhibited a violaceous-red, soft, non-tender, poorly mobile mass
measuring 2.8cm × 1.4cm × 0.7cm (Panel A). The patient underwent complete tumor excision with eyelid reconstruction under general anesthesia. Histopathological analysis demonstrated a dermal tumor composed of monotonous cells with scant cytoplasm, high nuclear-to-cytoplasmic ratio, finely granular chromatin, and frequent mitotic Figures 1 (Panel B). Immunohistochemistry revealed diffuse positivity for CK20 (perinuclear dot-like) (Panels C), Synaptophysin (Panels D), INSM1, and CAM5.2 (perinuclear dot-like), with a Ki-67 proliferation index of 70%, confirming the diagnosis of Merkel cell carcinoma. Postoperatively, the patient received adjuvant radiotherapy (45 Gy) and remained recurrence-free during six months of follow-up.
