Can smoking and/or occupational UV exposure have any role in the development of the morpheaform basal cell carcinoma? A critical role for peritumoral mast cells

Background The stroma of basal cell carcinoma (BCC) is rich in mast cells. Morpheaform BCC has been reported to contain many more mast cells than the other types of BCC. However, pathogenesis and clinical relevance of this observation are currently unclear. Smoking and ultraviolet (UV) exposure have recently been suggested to be related to the development of morpheaform BCC. Methods With a retrospective study, we aimed to investigate the possible roles of smoking and occupational UV exposure in the development of morpheaform BCC through the quantification of peritumoral mast cells. Our case population consisted of 34 patients with morpheaform BCC and 50 patients with solid BCC. After identification of mast cells with toluidine blue stain, a mast cell index was determined in each case. Results Mean mast cell index of morpheaform BCCs was significantly higher than that of solid BCCs (P 0.05), irrespective of the tumor type. Morpheaform BCC was significantly more frequent in smokers compared to solid BCC (P