Recurrent lentigo maligna as amelanotic lentigo maligna melanoma

Amelanotic lentigo maligna and lentigo maligna melanoma are extremely rare tumours. Even rarer is a recurrent amelanotic lentigo maligna or amelanotic lentigo maligna melanoma at the site of a previously removed pigmented lentigo maligna. We describe two cases of recurrent amelanotic lentigo maligna melanoma manifesting as erythematous plaques evolved from previously excised pigmented lentigo maligna.     

Amelanotic lentigo maligna and amelanotic lentigo maligna melanoma: a report of three cases mimicking intraepidermal squamous carcinoma

The clinical diagnosis of amelanotic melanoma may pose diagnostic difficulties. We report three cases of amelanotic lentigo maligna, two of which developed an invasive component (lentigo maligna melanoma). The clinical appearances in each case mimicked intraepidermal squamous carcinoma.     

Surgical treatment of lentigo maligna and lentigo maligna melanoma

Lentigo maligna (LM) is well known as an irregularly pigmented macular lesion usually presenting on the sun-damaged head and neck of older patients. Lentigo maligna (LM) has the potential to develop into invasive melanoma (LMM). A method of surgical excision for the treatment of LM and LMM using paraffin sections with tissue mapping to ensure clear margins before delayed defect closure is described. The results of applying this method in the treatment of 66 cases over a 40 month period are presented. Thirty-eight per cent of cases required two excisions or more to clear the tumour and 32% of cases showed evidence of invasive melanoma. Only one case has recurred thus far, and none have developed metastatic disease.     

Subungual lentigo maligna

A case of subungual lentigo maligna and a review of the literature is presented. Pigmented lesions involving the nail bed are rare, and should arouse clinical suspicion. Examination of biopsy specimens of these lesions is essential to rule out malignancy. The treatment of choice of lentigo maligna is surgical excision.     

Lentigo maligna and lentigo maligna melanoma

Lentigo maligna (LM) is a pigmented lesion that occurs on the sun-exposed skin, particularly the head and neck areas, of an older patient. The lesion increases in size and at some point, often many years after its onset, may become lentigo maligna melanoma (LMM). For this reason, most authors consider LM a form of melanoma in situ. Treatment includes surgical or destructive modalities; the preferred form of therapy is surgical removal. Histopathologic features include a proliferation of atypical melanocytes along the basal layer of the epidermis and adnexal structures. This article discusses the clinical, histopathologic, and epidemiologic features of LM. The prognosis and treatment of LM are reviewed. Although the lifetime risk of the development of LMM is unclear, LMM is discussed briefly.     

The risk of progression of lentigo maligna to lentigo maligna melanoma

An analysis is presented which estimates the risk of progression of lentigo maligna (LM) to lentigo maligna melanoma (LMM) in U.S. whites using three data sources: the Health and Nutrition Examination Survey I for estimation of the age-specific prevalence of LM; the Surveillance, Epidemiology, and End Results Program for estimation of the age-specific incidence of melanoma; and the data from three melanoma registries for estimation of the age-specific case fraction of LMM among all invasive melanomas. The risk varies with age and is likely to be greater than estimated here for patients who present themselves for evaluation of changes in a lesion of LM. Our analysis suggests that the risk of progression from LM to LMM is substantially lower than is commonly believed.     

Fractionated radiotherapy of lentigo maligna and lentigo maligna melanoma in 64 patients

Between 1987 and 1998, 64 patients with lentigo maligna (LM) (n = 42) or lentigo maligna melanoma (LMM) (n = 22) were treated by fractionated radiotherapy. In all 22 patients with LMM, excision of the nodular part of the LMM was performed before radiation of the residual lentiginous tumor. During the follow-up period of 1 to 96 months (mean, 23 months; median, 15 months), none of the 42 patients with LM displayed any signs of recurrence of LM after radiation therapy alone. Of the 22 patients with LMM, only 2 patients showed local recurrence of the tumor, salvaged by excision in both cases. One patient with LMM suffered from metastatic disease without local recurrence of the melanoma 44 months after radiation therapy. The cosmetic results of radiotherapy were good or excellent in the vast majority of patients, with only a few experiencing hypopigmentation or hyperpigmentation in the irradiated area. Fractionated radiation therapy with superficial x-rays is an effective method of treatment of LM associated with low morbidity and leading to clinical results comparable to those of surgical excision.     

Cryotherapy for lentigo maligna

Eleven patients, 10 with lentigo maligna (LM) and one with lentigo maligna melanoma (LMM), were treated with cryotherapy. The symptoms cleared in all patients except one with LM. There were recurrences in four patients and three cleared with further treatment.     

Treatment of lentigo maligna

Lentigo maligna (LM) is the in situ phase of lentigo maligna melanoma (LMM) and, if left untreated, 30-50% of cases will progress to LMM, which is now thought to behave as aggressively as any other melanoma. Literature on the of treatment of LM including conventional surgery, micrographic Mohs surgery, cryosurgery, radiotherapy, electrodesiccation and curettage, 5-fluorouracil (5-FU), azelaic acid, retinoic acid and lasers are reviewed. It is concluded that micro-graphic Mohs surgery has the lowest recurrence rates and that conventional surgery, cryosurgery and radiotherapy all have recurrence rates in the order of 7-10%. Therefore, on the basis of the current literature available, all three of these methods could be recommended as primary treatment of LM. It is extremely important when choosing one of the above treatments that the physician is adequately trained in the appropriate technique and understands the limitation of the method used and the need for close follow up of the patient     

From melanotic to amelanotic lentigo maligna: an aggressive variant presenting as an inflammatory lesion

A 79-year-old woman presented to us with an erythematous macule of the left cheek, approximately 4 cm in diameter. She reported slow enlargement of the lesion over the previous 12 months. Clinically the lesion showed irregular borders and changing erythematous discoloration, as well as slight scaling. The diagnosis at the time of presentation was rosacea-like dermatitis. The lesion was situated besides and within the site of a skin transplant.
The patient's medical history revealed a first excision of a pigmented lentigo maligna 17 years previously (Fig. 1). Multiple recurrences of the pigmented lentigo maligna had been treated surgically 13, 6, 5, and 2 years prior to the latest clinical consultation, showing the clinical and histologic features of pigmented lentigo maligna.
Because of this medical history, biopsies were performed which exhibited the histologic characteristics of amelanotic lentigo maligna. To confirm the melanocytic nature of the tumor cells, immunohistochemical analyses were carried out using S-100 protein (Dako, Germany), HMB45 (Dako, Germany), and NK/C3 (Biogenex, USA) antibodies and the ABC method (Vectastain, USA) with 3-amino-9-ethylcarbazol (AEC) as the chromogen. The cells expressed all three markers (Fig. 2), while the Fontana stain for melanin pigment failed to indicate the pigment.
Histologically, as seen in Fig. 3, the first lentigo maligna excised demonstrates deposits of melanin pigment in melanophages and pigmented tumor cells, as well as a lichenoid and perifollicular infiltrate of lymphocytes and some macrophages. The histologic specimen shown in Fig. 4 demonstrates the biopsy taken 17 years later, where no melanin pigment can be observed within the tumor cells, which show a pagetoid infiltrating pattern of the epidermal layers. The inflammatory infiltrate is comparable with that seen in the first specimen, while regression was not observed. The solar elastosis of the upper dermis has markedly progressed.