Amelanotic lentigo maligna managed with topical imiquimod as immunotherapy

Clinically amelanotic lentigo maligna often resembles an inflammatory lesion rather than a melanoma in situ. We present two cases of extensive amelanotic lentigo maligna presenting as gradually enlarging erythematous patches on the faces of women following incomplete excisions of lentigo maligna. Because of their site and size, therapeutic options were limited; the lesions have, however, resolved (clinically and histologically) following the topical application of 5% imiquimod cream. We discuss the rationale for the use of imiquimod in the treatment of lentigo maligna.     

Amelanotic lentigo maligna melanoma manifesting as a dermatitislike plaque

A 72-year-old man with a previous history of an amelanotic melanoma on his left forearm had an erythematous plaque excised from his right shoulder. Although the clinical impression was a dermatitis, a biopsy specimen revealed an amelanotic lentigo maligna melanoma. To our knowledge, this is the first patient described with an amelanotic lentigo maligna melanoma as a second primary tumor to an apparent previous amelanotic melanoma, manifesting as a dermatitislike plaque.     

Following lentigo maligna may not prevent the development of life-threatening melanoma.

BACKGROUND--Management of lentigo maligna (Hutchinson's melanotic freckle, in situ lentigo maligna melanoma) by regular observation relies on the detection of invasive melanoma before it has developed significant life-threatening potential. Recent studies indicate that lentigo maligna melanoma does not have a better prognosis than other forms of melanoma. OBSERVATIONS--A case is reported of an amelanotic lentigo maligna that evolved from a macular lesion to a deeply invasive, amelanotic, lentigo maligna melanoma within 6 months. The melanoma was Clark level IV and measured 3.0 mm in maximum tumor thickness. CONCLUSIONS--Observation of lentigo maligna at 6-month intervals would not seem to be sufficiently reliable in detecting the development of invasive lentigo maligna melanoma before it becomes a life-threatening disease. Early surgical excision is the treatment of choice.     

Amelanotic lentigo maligna melanoma: a unique case and review of the literature

It has been estimated that 2 percent of all melanomas are clinically amelanotic, with amelanotic lentigo maligna melanoma being an even rarer presentation. These neoplasms have presented clinically as neurodermatitis, eczema, and erythema. Given the lack of clinical markers and subsequent delay in diagnosis of these lesions, they are potentially more dangerous than pigmented lentigo maligna melanomas. We report a case of an amelanotic lentigo maligna melanoma presenting as an ill-defined edematous area on the left cheek of an elderly woman.     

Macular amelanotic melanoma in situ

This report aims at directing the attention to the rare entity of amelanotic melanoma in situ, as exemplified in a patient who had an amelanotic lentigo maligna 10 years ago and a recurrent lesion of identical clinical and histological (except for pagetoid tumor cells in the epidermis) appearance 4 years ago. Amelanotic melanomas in situ appear as inconspicuous reddish macules, which can hardly be diagnosed or even suspected on clinical grounds.     

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.     

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.     

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.     

A clinically invisible melanoma

We report a case of an amelanotic lentigo maligna incidentally found on a shave biopsy in an 87‐year‐old woman. Amelanotic lentigo maligna is a rare variant of lentigo maligna. It is often reported as presenting as erythematous scaly macules and is usually confused as benign dermatoses. Here were present a case of amelanotic lentigo maligna with no visible or palpable features.     

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.     

Unstable solar lentigo: A defined separate entity

An unstable solar lentigo is a solar lentigo with areas of melanocytic hyperplasia not extending past the margin of the lesion. They are discrete, macular, pigmented lesions arising on sun‐damaged skin and a subset of typical solar lentigos. Clinically they differ from usual solar lentigines in often being solitary or larger and darker than adjacent solar lentigines. These lesions are of clinical importance as they can arise in close proximity to lentigo maligna and in a single lesion there can be demonstrated changes of solar lentigo, unstable solar lentigo and lentigo maligna. These observations led us to conjecture that unstable solar lentigos could be a precursor lesion to lentigo maligna. In this article we examine the possibility that lentigo maligna can arise within a solar lentigo through an intermediate lesion, the unstable solar lentigo. We propose that the histopathological recognition of this entity will allow for future research into its behaviour and thus management. We review difficulties in the diagnosis of single cell predominant melanocytic proliferations and the concept of unstable lentigo in view of the literature and clinical experience supporting the proposal of its recognition as a separate entity.     

Series of Fourteen Cases of Topical Imiquimod 5% in Lentigo Maligna: Treatment Modalities and Clues for Detecting Recurrences

Topical imiquimod has been used off-label as monotherapy or adjuvant treatment for lentigo maligna. Our aim is to describe treatment modalities, clinical outcomes, and management of recurrence in patients receiving imiquimod for lentigo maligna.Patients from our unit with lentigo maligna or lentigo maligna melanoma treated with imiquimod 5% as monotherapy or in combination with surgery were included in this study.Fourteen cases were recruited (85.7% lentigo maligna and 14.3% lentigo maligna melanoma). Eight patients (57.1%) received imiquimod without surgery, and six (42.9%) underwent narrow excision before beginning treatment. During the follow-up period, pigmentation reappeared in 6 patients (4 postinflammatory hyperpigmentation and 2 relapses). Relapses were managed with very narrow excision (1 mm margin) and retreatment with imiquimod 5%.All imiquimod modalities showed well-tolerated side effects and low recurrence rates, with long periods of follow-up. Imiquimod appears to be a versatile option for treating LM in suitable candidates.     

Imiquimod: a novel treatment for lentigo maligna

Lentigo maligna is the in situ phase of lentigo maligna melanoma, and if left untreated it may progress to invasive melanoma. It most commonly occurs on the exposed sites of the face and neck of middle-aged or elderly patients. Conventional surgery using a 5-10 mm margin is the recommended treatment; however, lesions can be quite large and surgical removal may involve extensive plastic repair. We report an elderly patient with a large lentigo maligna on the scalp who was reluctant to have surgery. We tried topical imiquimod 5% cream (Aldara), a local immunomodulator, which has recently become available for the treatment of external genital and perianal warts. Initially used over a test area and then over the whole of the lesion, for a total of 7 months, the imiquimod cream resulted in complete clinical and histological cure. The patient has been followed up for 9 months without evidence of recurrence.     

Amelanotic malignant melanoma following cryosurgery for atypical lentigo maligna

Cryosurgery is an alternative treatment option to surgical excision for lentigo maligna. Clinical evidence of recurrence is usually characterized by repigmentation at the treated site. We report two patients who developed amelanotic malignant melanoma following cryosurgery for a pigmented lentigo maligna. These cases illustrate the potential risk of treating lentigo maligna with cryosurgery.     

[Artículo traducido] Serie de 14 casos de tratamiento con imiquimod tópico al 5% en lentigo maligno: modalidades terapéuticas y claves para detectar recidivas

Topical imiquimod has been used off-label as monotherapy or adjuvant treatment for lentigo maligna. Our aim is to describe treatment modalities, clinical outcomes, and management of recurrence in patients receiving imiquimod for lentigo maligna.Patients from our unit with lentigo maligna or lentigo maligna melanoma treated with imiquimod 5% as monotherapy or in combination with surgery were included in this study.Fourteen cases were recruited (85.7% lentigo maligna and 14.3% lentigo maligna melanoma). Eight patients (57.1%) received imiquimod without surgery, and six (42.9%) underwent narrow excision before beginning treatment. During the follow-up period, pigmentation reappeared in 6 patients (4 postinflammatory hyperpigmentation and 2 relapses). Relapses were managed with very narrow excision (1 mm margin) and retreatment with imiquimod 5%.All imiquimod modalities showed well-tolerated side effects and low recurrence rates, with long periods of follow-up. Imiquimod appears to be a versatile option for treating LM in suitable candidates.     

Rapid progression of lentigo maligna to deeply invasive lentigo maligna melanoma. Report of two cases

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

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.     

One-year follow-up of a lentigo maligna: first dermoscopic signs of growth

We report a 64-year-old man with a pigmented lesion on his forehead, initially thought to be actinic lentigo. At follow-up 1 year later the lesion had increased in size and showed new areas of pigmentation. Dermoscopic observation and biopsy led to a diagnosis of lentigo maligna and the lesion was excised. The dermoscopic features indicative of early growth of lentigo maligna are identified and discussed.     

Desmoplastic melanoma associated with an intraepidermal lentiginous lesion: case report and literature review

Desmoplastic melanoma tends to present as firm, amelanotic papules. Microscopically, it reveals a proliferation of fusiform cells in the dermis and variable collagen deposition, as well as intraepidermal melanocytic proliferation of lentiginous type in most cases. Biopsy in a 61-year-old white male patient, who had received a diagnosis of lentigo maligna on his face 10 years before, revealed a proliferation of dermal pigmented spindle cells and collagen deposition, reaching the deep reticular dermis, with a lentiginous component. Immunohistochemistry with S-100, Melan-A and WT1 showed positivity, but it was weak with HMB45. Desmoplastic melanoma associated with lentigo maligna was diagnosed. Several authors discuss whether desmoplastic melanoma represents a progression from the lentiginous component or arises "de novo". Desmoplastic melanoma represents a minority of cases of primary cutaneous melanoma (less than 4%). Identification of lentigo maligna indicates that desmoplastic melanoma should be carefully investigated.     

Argon laser treatment of lentigo maligna

A 64-year-old man had an irregularly pigmented lentigo maligna over the bridge of his nose. Melanin readily absorbs argon light, and the superficial location of this pool of epidermal and appendageal chromophore suggested that laser therapy might permit relatively selective lesion destruction. Argon laser surgery was performed on Nov. 9, 1981, and the treated site had remained clear to the time of writing. Selected patients with pigmented lesions may respond well to argon laser radiation, but close posttreatment clinical and histologic assessment is essential.