Chondrosarcomatous Differentiation in a Large Malignant Melanoma of the Scalp

Background. Divergent differentiation in malignant melanoma is a rare phenomenon, which can lead to delayed diagnosis or misdiagnosis, impacting upon patient treatment and outcome, as well as the understanding of tumour behaviour. Case. We present the case of a large long-standing tumour on the scalp of a 72-year-old female patient, which when excised and examined histologically was revealed to be a nodular malignant melanoma displaying chondrosarcomatous differentiation. Foci suggestive of lentigo maligna were also present. Rapid metastatic spread of the tumour was observed shortly after the primary resection. Discussion. To our knowledge, this is the first reported case in the literature of chondrosarcomatous differentiation in a lentigo maligna melanoma. The clinical and histopathological details and images of this case are presented alongside a discussion regarding such tumours and patterns of similar tumour behaviour.