We report the case of a 53-year-old patient with a nodule on her right labium majus whose histological and immunohistochemical profile (S100 and p16) confirmed a diagnosis of vulvar myxoid liposarcoma.
Careful attention should be paid to the presence of a firm dermal nodule and atypical scar lesions especially in sun-exposed areas (mainly head and neck region) in elderly patients associated with S100-positive spindle cell proliferation, solar elastosis and adjacent atypical melanocytic proliferation.
Immunohistochemistry of spindled cells both inside and outside the nodule showed S100 positivity with the absence of other melanocytic markers (HMB-45, Melan-A).
The adjacent solid sarcomatoid spindle cell nodulelacked expression of S100 protein, SOX10, as well as melan-A, gp100, and microphthalmia-associated transcription factor in >95% of its tumor cells.