Role of Wnt signaling in dermatofibroma induction phenomenon

Dermatofibroma (DF) is a common benign skin neoplasm. Induction above DF lesions, including follicular unit induction, is a frequently observed phenomenon. Wnt signaling is known to be critical in hair follicle morphogenesis. Our study assesses the role of Wnt signaling in DF induction by evaluating intracellular localization of β-catenin in various types of DF induction.

Archived tissue collected between 1 October 1980 and 1 October 2013 was stained per protocol using hematoxylin and eosin and anti-β-catenin monoclonal antibody. Specimens were grouped into categories based on the presence or absence and type of induction. All specimens were scored for nuclear β-catenin localization.

Of 62 specimens, 42 (68%) showed induction while 20 (32%) showed none. Nuclear β-catenin staining was detected in 23 (55%) of the induction and in none of the no-induction specimens (P-value < 0.001). Types of induction included: 15 (24%) follicular induction, 31 (50%) acanthosis, and 4 (6%) sebaceous induction. For follicular induction, 13 (87%) showed positive nuclear β-catenin staining compared to 11 (35%) for acanthosis and 1 (25%) for sebaceous induction (P-value = 0.002).

Our findings support the hypothesis that DFs promote an ectopic activation of Wnt pathway signaling in follicular induction phenomenon.