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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.
The results of treatment of 42 cases of lentigo maligna and 16 of lentigo maligna melanoma at the New York University Medical Center was reviewed. The recurrence rate after surgical excision of 22 lesions of lentigo maligna was 9% (2/22), but after treatment of 20 such lesions with destructive techniques (X rays, curettage-electrodesiccation, cryosurgery), it was 35% (7/20). Of 11 cases of lentigo maligna melanoma that were excised, none recurred locally, but fatal metastases ensued in one case. Five patients who were eventually classified as having lentigo maligna melanomas had been treated by destructive techniques. In four of them there were local recurrences and in two, metastases as well; the fifth patient had metastases without local recurrence. On the basis of this review of these 58 cases, we conclude that surgical excision and careful histologic study of step sections through the entire lesion insure accurate diagnosis and provide the highest cure rates for lentigo maligna and lentigo maligna melanoma.
With fluorescence-histochemical methods (formalin-induced fluorescence), the different stadia of development of lentigo maligna (Morbus Dubreuih) and lentigo maligna melanoma were investigated. In this way, the special stadia can be clearly characterized using the fluorescence-microscope. In the earliest stadium of malignancy, only the pigment-cells of the basal part of the epidermis seem to be numerous. At this time, these cells are mainly arranged as palisades in the basal layer, and their strongest dendrites are usually directed towards the corneal layer. As the malignancy progresses, the pigment-cells are arranged in several layers in the basal epidermis. In this case, polymorphism of the cells is obvious and their dendrites spread in all directions. A further stadium shows pathological alterations resembling a lentigo with long rete ridges. The atypical cells cluster together into the so-called pseudonests, predominantly at the tips of these rete ridges. With the fluorescence-microscope, dendrites are seldom visible here. In the stadium of tumorous growth, all above-described alterations of the epidermis in lentigo maligna are no longer detectable. Malignant cells in the dermis, which form as a tumor mode, seldom show dendrites. These cells are mainly round or oval-shaped; at best there are some spindle cells in certain areas of the tumor. The epidermis covering the tumor node is infiltrated by some tumor cells but the characteristic alterations as described above for the various stadia of lentigo maligna are no longer visible. Even fluorescence-microscopically, a tumor node of lentigo maligna does not seem to be different from a primary nodular melanoma or a tumor node of a superficial spreading melanoma, if the flat parts of the tumors are not considered in the diagnosis.
BACKGROUND: The use of frozen sections in the management of lentigo maligna and lentigo maligna melanoma has been the focus of some controversy. OBJECTIVE: Our purpose was to utilize paraffin-embedded tangential sections in the management of two cases of lentigo maligna and three cases of lentigo maligna melanoma. METHODS: A modification of Mohs micrographic surgery using rush paraffin-embedded sections with adjunctive immunoperoxidase staining (HMB-45) and supplemental vertical sections was employed. RESULTS: This method resulted in enhanced histologic evaluation of section margins and did not compromise the diagnosis of the primary invasive melanoma or Breslow measurements. CONCLUSION: Mohs micrographic surgery modified by the use of rush paraffin-embedded sections allows adjunctive immunoperoxidase staining and supplemental vertical sections that may be helpful in the management of lentigo maligna and lentigo maligna melanoma.
We report on a patient developing simultaneous occurrence of lentigo maligna lesions, solar lentigines and an extensive melanosis of the oral mucosa. Diagnostically, epiluminescence microscopy had a relevant role in the preoperative assessment and selection of suspicious pigmented lesions, as the lesions histologically labelled as lentigo maligna and solar lentigo were clinically indistinguishable. We review the clinical, dermoscopic and histopathologic differential diagnosis of solar lentigo, malignant lentigo and mucosal melanosis with other melanocytic and keratinocytic lesions and discuss the possible relationship between these entities.
Lentigo maligna is a precancerosis or a melanoma in situ, whose level of malignancy has not yet been definitively clarified. Recurrences are not rare after excision, even when an ample safe margin is observed. One reason for this is the existence of a subclinical ramification in the marginal area of the lentigo maligna. Such subclinical ramifications were investigated by means of excision with histological monitoring of the margins by the paraffin section technique. There was a clear relationship between the frequency of these ramifications and the clinical safe margin left in 64 excisions. With the aid of parametric evaluation methods the distribution of the subclinical portion referred to the distance from the clinical margin could be determined with a special formula. If an invasion, in the form of a lentigo maligna melanoma had already taken place, then the subclinical portion within the marginal area was significantly more extensive. For the treatment of lentigo maligna, and especially of lentigo maligna melanoma, we therefore recommend excision with histological monitoring of the margins. There were no local recurrences within an average follow-up period of about 2 1/2 years.
Some authors have considered lentigo maligna to be an atypical melanocytic proliferation, whereas others have considered it to be melanoma in situ. We reviewed 50 cases of lentigo maligna. We have identified two subsets of lesions. The first has atypical melanocytic hyperplasia, which we postulate to be correctly designated lentigo maligna. The second subset has the following features in addition to the melanocytic hyperplasia: individual and nests of cells at varying layers of the epidermis, confluence of the melanocytes replacing the basilar region, uniformity of the cytological atypia, and nesting of uniformly atypical melanocytes. These lesions we designate as malignant melanoma in situ, lentigo maligna type. We are proposing that the lesions that have been termed lentigo maligna represent a spectrum of atypia and that the application of some of the traditional features for the diagnosis melanoma may permit the segregation of more and less aggressive lesions.
BACKGROUND AND DESIGN: Pigmented lesions that are black and have an irregular outline are often considered suspicious for melanoma; however, these features may be seen in benign lesions. The reticulated black solar lentigo is such a lesion and is described in a clinicopathologic study of nine lesions in eight patients. RESULTS: The "ink spot" lentigo is distinguished clinically by its color and wiry or beaded, markedly irregular outline. It has a reticulated pattern and most resembles a spot of ink on the skin. In this series of patients, the lesions were limited to sun-exposed areas of the body and had a distribution pattern similar to that of solar lentigines. Although all the patients were of Celtic ancestry and had numerous solar lentigines, they usually had only one black lentigo (range, one to four; mean, 1.6; median, one). Histologic evaluation, including electron microscopy and dopa-incubated vertical sections, demonstrated lentiginous hyperplasia of the epidermis, marked hyperpigmentation of the basal layer with "skip" areas that involved the rete ridges, and a minimal increase in the number of melanocytes. CONCLUSIONS: Because of their dark color, irregular border, and limited number, reticulated black solar lentigines were of concern to patients and primary care physicians. However, the characteristic features of these lesions allow one to make the clinical diagnosis of a benign lentigo.
In vivo confocal microscopy can noninvasively image thin en face sections within living intact human tissue with high resolution and contrast. This evolving technique may provide clinicians with tools to help detect lentigo maligna lesion progression in vivo and may be important in defining tumor margins, thus providing a more definitive surgical eradication of lentigo maligna and malignant melanoma in situ, lentigo maligna type. We present a case of malignant melanoma in situ, lentigo maligna type, and we describe the images seen with confocal microscopy in correlation with routine histopathology.
Two patients had lesions of lentigo maligna that evolved into deeply invasive (level 4-5) lentigo maligna melanoma during a relatively short period (two years and four years, respectively). In both patients, the clinical impression of lentigo maligna had been difficult to confirm by histopathologic analysis until the invasive tumor had developed. Both patients were actively followed up during this period of evolution, with our intention of detecting any early changes suggestive of invasive melanoma. Since deep invasion developed despite close clinical supervision, a more aggressive approach to the treatment of lentigo maligna may be warranted.
Lentigo maligna is the preinvasive stage of lentigo maligna melanom, which is a specific type of cutaneous malignant melanom found almost exclusively in the head and neck area. The distinguishing features and the biological behavior of this disease are discussed. Emphasis is placed on early diagnosis by clinical differentiation from other pigmented lesions and by biopsy specimen. Treatment by adequate surgical removal with appropriate reconstruction is discussed and illustrated with case reports.
Between 1958 and 1977, 8 cases of lentigo maligna (LM) and 15 cases of lentigo maligna melanoma (LMM) were treated with radiotherapy at the Princess Margaret Hospital. Only 1 of the 8 cases of LM recurred following irradiation and this recurrence was controlled with further radiotherapy. Of 15 cases of LMM, 14 were controlled by irradiation for periods ranging from two months to six years postradiotherapy; the 1 recurrence was salvaged with local excision. Conventional orthovoltage irradiation using doses of 4500--5000 rad in ten to 15 fractions has been found to be highly effective in controlling this disease. The lesion may take up to 24 months to completely regress following irradiation. The benefits of this modality of treatment for a disease process which predominantly occurs in the head and neck region of elderly people is discussed in detail. The results are compared with other methods of irradiation (Miescher's technique) and other modalities of treatment.
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.
Thirty-eight cases of lentigo maligna and 22 cases of lentigo maligna melanoma, were reviewed in order to compare cure rates of various methods of treatment. Surgical excision resulted in the best cure rate (91%); destructive modalities were less successful (45%). All lesions treated with 5% 5-fluorouracil recurred.
BACKGROUND: Lentigo maligna (LM) is a pigmented neoplasm on sun-exposed skin of elderly patients. LM slowly increases in size and may become lentigo maligna melanoma (LMM), a potentially fatal malignancy. Complete excision is the treatment of choice. Mohs' micrographic surgery (MMS) with frozen and permanent sections may be used for complete eradication of the lesion, while sparing as much normal tissue as possible. The authors studied the efficacy of MMS for the treatment of LM and LMM. METHODS: Between 1985 and 1992, 45 patients with LM (26) and LMM (19) were treated with MMS. The authors' technique was to use examination of frozen sections and rush permanent sections (prepared and read within 24 hours). Positive frozen sections warranted further excision. For negative or equivocal frozen sections, surgery was interrupted until the examination of permanent sections was performed. RESULTS: All 45 patients were free of local disease and evidence of metastases at an average of 29.2 months (range, 4-81 months) after therapy. CONCLUSIONS: MMS aided by rush permanent sections yielded a prolonged disease free survival for all 45 patients with LM or LMM. Because the MMS technique minimizes the removal of normal tissue, and the local cure rate in this study was superior to that reported for conventional surgery, the authors recommend this technique for the treatment of LM and LMM.
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.
Lentigo maligna (LM) and lentigo maligna melanoma (LMM) are distinct entities from other forms of melanoma, occurring predominantly on the skin of the head and neck in elderly people, having a slow growth rate and a low metastatic potential (10%). Twenty-three patients with LM were treated with conventional fractionated irradiation, 18 were locally controlled and two failed locally both of whom, however, were salvaged with further treatment. Three patients are not evaluable because of short follow-up time. Median time to complete regression of the lesion is seven months. Twenty-eight patients with LMM have been irradiated, 23 are locally controlled, two locally recurred (both retrieved with subsequent treatment), and three are inevaluable because of short follow-up time. One patient with a level 5 LMM has developed regional and distant metastases. It is concluded that irradiation is a simple effective method of treatment for this form of melanoma.
Forty cases of lentigo maligna (LM) and lentigo maligna melanoma (LMM) treated by conventional fractionated radiotherapy are reviewed. Fourteen of seventeen LM patients are alive and well 4 months to 5 years following irradiation, one patient died of intercurrent disease without recurrence, and two had residual or recurrent tumor (both salvaged by excision or further irradiation). Twenty-one of twenty-three LMM patients had their tumor controlled from 1 month to 7 years following irradiation. Two recurred locally or had residual tumor, and both were salvaged by excision. There have been no regional or distant recurrences of melanoma in the entire series. Cosmetic results of treatment are excellent. The lesions can take up to 24 months to disappear following irradiation. It is concluded that conventional fractionated radiotherapy is simple, effective outpatient treatment worthy of further study for LM and LMM.