Syringocystadenoma papilliferum arising in a naevus sebaceus

CASE REPORT A 56-year-old Malay lady with underlying type 2 diabetes mellitus, hypertension and gout was referred to our Dermatology Clinic by her local government clinic with a swelling over her right temporal scalp. A positive immunoreactivity for gross cystic disease fluid proteins 15 and 24 and zinc-2 glycoprotein demonstrates evidence of apocrine differentiation.4 However, immunohistochemical analysis of cytokeratins in syringocystadenoma papilliferum demonstrates similarities to eccrine poromas and the ductal component of eccrine glands.5 It is likely that SCAP arises from undifferentiated cells with the potential to exhibit both apocrine and eccrine characters. Malignant transformation of SCAP to basal cell carcinoma (BCC), squamous cell carcinoma (SCC), or syringocystadenocarcinoma papilliferum (SCACP) may occur.