Hyperpigmented and flesh-colored skin tags: what is the difference? A histopathological and immunohistochemical study

Background Skin tags (STs) are soft pedunculated benign tumors that occur mainly on the neck and major flexures. STs can be normochromic or hyperchromic, and although asymptomatic, they represent a cosmetic problem for patients. Objective The aim of the study was to detect and compare the difference between skin-colored and pigmented STs with respect to BMI, glucose tolerance, degree of acanthosis/ papillomatosis, melanocyte, and mast cell counts. Patients and methods A total of 20 adults with both types of STs within the neck area were included. Two biopsies were taken, one from a flesh-colored and another from a hyperpigmented ST, and stained using hematoxylin and eosin (for acanthosis/papillomatosis), melanoma marker (for melanocytes), and mast cell chymase (for mast cells). Results The degree of acanthosis/papillomatosis, melanocyte, and mast cell counts were significantly higher in pigmented STs (P= 0.001), which was found more in those with impaired glucose tolerance and in severely obese patients. Conclusion We attribute the change in STs color to melanocyte–mast cell interaction as well as to the degree of acanthosis/papillomatosis. Further studies are still required for a deeper understandingof reasons behind such change and for the clinical implications of such findings.