To report a case of amelanotic melanoma located in the leff upper eyelid misdiagnosed as chalazion in a 41-yearold
woman. Examination showed a red 2 cm × 2 cm mass in the left upper palpebral conjunctiva. The tumor
was excised and regular fixed in 10% formalin, embedded, sectioned, HE stained and immunohistochemistry
stained. Histopathological examination revealed nests of round atypical tumor cells with vacuolated cytoplasm
and sheets of spindle atypical tumor cells. Some tumor cells had conspicuous nucleoli. Immunohistochemistry
some tumor cells were positive for melanocytic markers S-100, HMB-45 and negative for CK, EMA. So the
pathological diagnosis was palpebral conjunctiva amelanotic melanoma in the leff upper eyelid. For the mass in
palpebral conjunctiva of senile patients without typical characteristics of chalazion, the surgical specimen should
be performed for pathologic examination to rule out other tumors.