Spread of a recurrent lentigo maligna into a graft: a case for conservative treatment

Lentigo maligna : prognosis and treatment options

Lentigo maligna is a premalignant melanocytic neoplasm occurring on the sun-exposed skin of the middle-aged and elderly. It is believed to represent the in situ phase of lentigo maligna melanoma and, as such, cure is usually the aim of treatment. However, factors such as site and size of lesion and patient co-morbidities may influence the treatment modality undertaken. Surgical excision is the treatment of choice to obtain clinical and histologic clearance, but many other modalities have been used with variable success. Mohs micrographic surgery is associated with the lowest recurrence rate at 4-5%, but conventional surgery, cryotherapy and radiotherapy also yield good results, with recurrence rates in the order of 7-10%. Other treatments have been tried but currently there are not enough data to support their routine use. In order to make the best decision regarding appropriate management of lentigo maligna, the dermatologist or surgeon must be aware of all the options available and the evidence supporting their use.

Prolonged evolution of a lentigo maligna

Lentigo maligna (LM) is a melanocytic lesion which is a potential precursor to melanoma and often has a prolonged intraepidermal growth phase before evolving into lentigo maligna melanoma (LMM). LM is also noted for its tendency to locally recur after treatment. We present a patient who had a persistent LM on her left cheek which, despite multiple excisions, persisted and transformed into a partially amelanotic LMM roughly three decades later. Our patient's course was also notable for this melanoma recurring at the edge of, and subsequently migrating into, a previously placed skin graft.