What we need to learn when exploring the mixed basal cell carcinoma of head and neck

Coexistence of different histopathological types of basal cell carcinomas (BCC) in the same anatomical localisation is rare, and, therefore, is engaging for histopathologists and clinicians. In many cases, the determination of a neoplasm type remains difficult, since BCC may consist of more than one histopathological subtype. Mixed BCCs often present with an aggressive course and recurrence when compared to other subtypes of a tumour. Furthermore, tumours of this type are associated with time-consuming treatment and not a very satisfactory cosmetic result, thus worsening the quality of the patient’s life. Several clinical studies have been published regarding the histopathologically diverse tumours developed in the same anatomical region; however, largely peculiarities of mixed BCCs are not explored sufficiently. The purpose of this study was to substantiate the use of dermoscopy and morphology, assessing mixed type BCC of the head and neck. The tumours were removed with a surgical excision of 1 cm margins, and the tumour sites were assessed in a 24-month-long follow-up period. The dermoscopic characteristics of mixed and aggressive BCC are analysed in this study. Finally, to better estimate the invading cone of the tumour, a complex morphology, which included collagen type IV and podoplanin immunohistochemistry, and electron microscopy were used.