Recurrent lentigo maligna melanoma commingling the tumour nests of a basal cell carcinoma

Abstract

There are various types and combinations of coexisting cutaneous neoplasms which have been documented in the past but are uncommon. In this report we describe a case of basal cell carcinoma (BCC) colonised by recurrent lentigo maligna melanoma. A review of the literature has established the coexistence of lentigo maligna and BCC in six cases. The unusual combination of melanoma and BCC poses a therapeutic and prognostic dilemma. BCC is known to have a favourable outcome whereas melanoma tends to behave in a more aggressive manner leading to a less favourable outcome. There are conflicting views as to whether these lesions should be treated as BCC's or lentigo maligna melanoma. Our case appears to be unique, in that it was a recurrent lentigo maligna melanoma which was colonising the BCC. We treated our patient with wide local excision and full thickness skin graft and will continue to observe him on an outpatient basis. There needs to be long term follow up of a larger number of patients for us to truly appreciate the biological significance of parasitism of BCC by lentigo maligna melanoma.