Double Immunohistochemical Labelling of PRAME and Melan A in Slow Mohs Biopsy Margin Assessment of Lentigo Maligna and Lentigo Maligna Melanoma

Introduction: Lentigo maligna (LM) and lentigo maligna melanoma (LMM) predominantly affect the head and neck areas in elderly patients, presenting as challenging ill-defined pigmented lesions with indistinct borders. Surgical margin determination for complete removal remains intricate due to these characteristics. Morphological examination of surgical margins is the key form of determining successful treatment in LM/LMM and underpin the greater margin control provided through the Slow Mohs micrographic surgery (SMMS) approach. Recent assessments have explored the use of immunohistochemistry (IHC) markers, such as Preferentially Expressed Antigen in Melanoma (PRAME), to aid in LM/LMM and margin evaluation, leveraging the selectivity of PRAME labelling in malignant melanocytic neoplasms. Methods: A Novel double-labelling (DL) method incorporating both PRAME and MelanA IHC was employed to further maximise the clinical applicability of PRAME in the assessment of LM/LMM in SMMS biopsies. The evaluation involved 51 samples, comparing the results of the novel DL with respective single-labelling (SL) IHC slides. Results: The findings demonstrated a significant agreement of 96.1% between the DL method and SL slides across the tested samples. The benchmark PRAME SL exhibited a sensitivity of 91.3% in the SMMS specimens and 67.9% in histologically confirmed positive margins. Discussion: This study highlights the utility of PRAME IHC and by extension PRAME DL as an adjunctive tool in the assessment of melanocytic tumours within staged excision margins in SMMS samples.

Is sentinel lymph node biopsy needed for lentigo maligna melanoma?

BACKGROUND AND OBJECTIVES

Sentinel lymph node biopsy (SLNB) is an area of debate in the management of lentigo maligna melanoma (LMM). The utility of SLNB and its prognostic value in LMM have not yet been studied with large databases.

METHODS

We performed a retrospective review of the National Cancer Database (2012-2020) and the Surveillance, Epidemiology, and End Results (2010-2019) database for patients with cutaneous nonmetastatic LMM with Breslow thickness >1.0 mm. Multivariable logistic regression identified factors associated with SLNB performance and sentinel lymph node (SLN) positivity. Univariable and multivariable analyses assessed overall survival (OS) and melanoma-specific survival (MSS) based on SLNB performance and SLN status.

RESULTS

Compared to other melanoma subtypes, LMM had lower rates of SLNB (66.6% vs. 80.0%-84.0%) and SLN positivity (11.3% vs. 18.6%-34.2%). Compared to patients who did not undergo SLNB, SLN status was significantly associated with improved OS in patients with SLN positive (HR = 0.64 [0.55-0.76]) and SLN negative (HR = 0.68 [0.49-0.94]), and worse MSS only in patients with positive SLN (HR = 3.93, p < 0.05).

CONCLUSION

The improved OS associated with SLNB likely implies surgical selection bias. Analysis of MSS confirms appropriate patient selection and suggests important prognostic value associated with SLN status. These results support continued SLNB for LMM patients according to standard guidelines.

Sentinel lymph node biopsy for lentigo maligna melanoma under local anaesthesia

BACKGROUND

Lentigo maligna melanoma is mainly localized in the head and neck region in elderly patients. Due to its slow horizontal growth, it has a good prognosis compared to other melanoma subtypes, but specific data are rare.

OBJECTIVES

The aim of this study was to investigate sentinel lymph node biopsy in lentigo maligna melanoma under local anaesthesia and to discuss the benefit.

METHODS

Investigation of patients with lentigo maligna melanoma and tumour thickness ≥1 mm treated at the Department of Dermatology, University Medical Centre Tuebingen, between January 2008 and October 2019.

RESULTS

In total, 204 patients (126 SLNB, 78 non-SLNB) with a median age of 75.7 years (SLNB: 73.3 years, non-SLNB: 79.7 years) could be included. Sixteen of 126 (12.7%) sentinel lymph nodes were positive. Five-year overall survival was 87.9% (88.5% SLNB; 87.4% non-SLNB) and 5-year distant metastasis-free survival was 85.8% (85.4% SLNB; 86.7% non-SLNB). There was no significant difference for distant metastasis-free survival (p = 0.861) and overall survival (p = 0.247) between patients with and without sentinel lymph node biopsy.

CONCLUSIONS

Sentinel lymph node biopsy in lentigo maligna melanoma under local anaesthesia is a safe and simple method, even in very old patients. However, LMM has a very good 5-year overall survival. In high-risk patients with high tumour thickness and/or ulceration, adjuvant immunotherapy can now be offered without the need to perform this procedure.

Racial-Ethnic, Education, and Socioeconomic Differences in the Treatment of Head and Neck Melanoma in situ: A Surveillance Epidemiology and End Results Population-Based Analysis

BACKGROUND

Incidence and treatment disparities for cutaneous melanomas have been documented among racial and sociodemographic minorities. However, the association between treatment types, race, and socioeconomic status remains unknown.

OBJECTIVE

To characterize treatment differences for head and neck melanoma in situ (MIS) and lentigo maligna (LM) based on race and sociodemographic variables.

MATERIALS AND METHODS

A population-based retrospective cohort study of the Surveillance Epidemiology and End Results database (1998-2016) was performed. Univariate and multivariate logistic regression modeling evaluated the association of race and US census-reported sociodemographic factors with Mohs micrographic surgery (MMS) utilization.

RESULTS

A total of 76,328 adult patients with head and neck MIS/LM were included. MMS accounted for 11.8% of total cases, with increased utilization observed since 1998-2002. Compared with areas with greater percentages of individuals completing high school (first quartile), patients living in the second (Odds ratio [OR] 0.71; 95% confidence interval [CI] 0.64-0.80; p < .001), third (OR 0.74; 95% CI 0.63-0.86; p < .001), and fourth quartiles (OR 0.44; 95% CI 0.35-0.55; p < .001) were less likely to undergo MMS for their MIS/LM.

CONCLUSION

Educational efforts and awareness can bridge the knowledge gaps of appropriate treatment in patients with head and neck MIS/LM.

The limited value of sentinel lymph node biopsy in lentigo maligna melanoma: A nomogram based on the results of 29 years of the nationwide dutch pathology registry (PALGA)

BACKGROUND

Lentigo maligna melanoma (LMM) predominantly presents in the head and neck of the elderly. The value of sentinel lymph node biopsy (SLNB) for LMM patients remains to be determined, as the reported average yield of positive lymph nodes is less than 10%. In this nationwide cohort study, we wanted to identify LMM patients with an increased risk of SLNB-positivity.

METHODS

LMM with an SLNB indication according to the 8th AJCC melanoma guidelines were retrospectively identified from the nationwide network and registry of histo- and cytopathology in the Netherlands (PALGA). A penalized (LASSO) logistic regression analysis was performed to determine the optimal combination of clinicopathological factors to predict a positive SLNB.

RESULTS

Between 1991 and 2020, 1989 LMM patients met our inclusion criteria. SLNB was performed in 16.7% (n = 333) and was positive in 7.5% (25/333). The false-negative rate was 21.9%. Clinically detectable regional lymph node (LN) metastases were found in 1.3% (n = 25). Clinicopathological characteristics best predictive for SLNB-positivity (Odds ratio; 95% CI) were age (0.95; 0.91-0.99), ulceration 1.59 (0.44-4.83), T4-stage (1.81; 0.43-6.2), male sex (1.97; 0.79-5.27), (lymph)angioinvasion (5.07; 0.94-23.31), and microsatellites (7.23; 1.56-32.7) (C-statistic 0.75). During follow-up, regional LN recurrences were detected in 4.2% (83/1989) of patients, of which the majority (74/83) had no evidence of regional LN metastases at baseline.

CONCLUSION

Our findings confirm the limited SLNB-positivity in LMM patients. Based on the identified high-risk clinicopathological features, a nomogram was developed to predict the risk of a positive SLNB.

Efficacy of imiquimod in the management of lentigo maligna

BACKGROUND

Lentigo maligna (LM) is a melanocytic proliferation occurring on photo-exposed skin that may progress to LM melanoma. Surgery is recommended as first-line treatment. Excision margins of 5-10 mm remain, without international consensus. Several studies have shown that imiquimod, an immunomodulator, induces LM regression. This study investigated the effect of imiquimod versus placebo in neoadjuvant settings.

PATIENTS AND METHODS

We performed a prospective, randomized, multicentre, phase III clinical study. Patients were randomly assigned in 1:1 ratio to receive imiquimod or placebo for 4 weeks, followed by LM excision 4 weeks after the last application of imiquimod or placebo. The primary endpoint was extra-lesional excision, with a 5 mm margin from the residual pigmentation after imiquimod or vehicle. Secondary endpoints included the gain on the surface removed between the two groups; number of revision surgeries to obtain extra-lesional excisions; relapse-free time; and number of complete remissions after treatment.

RESULTS

A total of 283 patients participated in this study; 247 patients, 121 patients in the placebo group and 126 in the imiquimod group, accounted for the modified ITT population. The first extralesional extirpation was performed in 116 (92%) imiquimod patients and in 102 (84%) placebo patients; the difference was not significant (p = 0.0743). Regarding the surface of LM, imiquimod reduced the LM surface (4.6-3.1 cm2 ) significantly (p < 0.001) more compared to the placebo (3.9-4.1 cm2 ).

CONCLUSION

Imiquimod reduces the lentigo maligna surface after 1 month of treatment, without a higher risk of intralesional excision and with a positive aesthetic outcome.

RECURRENT LENTIGO MALIGNA: CONSERVATIVE CONTINUOUS TREATMENT WITH IMIQUIMOD OR REPEATED SURGERY? A LONG-TERM FOLLOW-UP DERMOSCOPIC CASE STUDY

A case of recurrent lentigo maligna in a 45-year-old woman is presented. The disease relapsed several times following the surgical excision of the lesion. An alternative treatment with imiquimod 5% cream was then used. After 4 years of follow-upfrom the last surgery, this treatment achieved total clearance of the lesion. The problems of lentigo maligna diagnosis and treatment are discussed.

Long-term outcomes of margin-controlled excision for eyelid melanoma

OBJECTIVES

To provide evidence for long-term outcomes for margin-controlled excision of eyelid melanoma.

METHODS

Retrospective single-centre observational case series of patients treated for eyelid melanoma between 2007 and 2016, with a minimum of 5-year follow-up. Tumour excision involved rush-paraffin en face horizontal sections and delayed repair (Slow Mohs; SM).

RESULTS

Twenty-two cases were seen with a survival of 91% (two deaths from nodular and lentigo maligna melanoma) and seven with melanoma in situ (MIS). Invasive melanoma includes eight lentigo maligna melanoma, four nodular, two amelanotic and one desmoplastic. Mean Breslow thickness was 6 mm for invasive (range 0.5-26). Mean excision margin for MIS was 3 mm (range 2-5 mm) and for invasive was 5 mm (range 2-10). Further excisions were performed in nine (41%); two went on to recur. Local recurrence was 36%; six invasive (27%) at a mean of 24 months (range 1.5-5 years) and two for MIS at a mean of 15 months (range 1-1.5 years). Imaging occurred for suspected advanced disease. Sentinel node biopsy was not performed. Advanced melanoma therapy was performed in two cases. No vitamin D testing occurred.

CONCLUSIONS

Survival rates are in line with 90% overall survival in the UK. Prescriptive excision margins are not applicable in the periocular region and margin-controlled excision with a delayed repair is recommended, but patients need to know further excision may be needed to obtain clearance. Evidence recommending vitamin D therapy needs to be put into clinical practice. In addition, upstaging of MIS occurred advocating excision rather than observation of MIS. More studies are needed to determine the best management of eyelid melanoma.

Periocular invasive melanoma manifestation in a patient using bimatoprost: case report and literature review

Prostaglandin F2a analogs (PGAs) are considered efficacious in the first-line treatment of glaucoma. They have however been associated with a number of periocular side effects. We present a case of periocular hyperpigmentation and progression to lentigo maligna melanoma (LMM) in a patient using bimatoprost eye drops. We conducted a literature review regarding the etiology and pathophysiology of periocular pigmentation in this setting.A 71-year-old female Caucasian patient with open-angle glaucoma using bimatoprost exclusively in her right eye noticed an ipsilateral lower eyelid/upper cheek area dark lesion after commencing treatment. Examination demonstrated a heterogeneously pigmented lesion. Excisional biopsy demonstrated extensive lentigo maligna (melanoma in situ) with superficially invasive malignant melanoma in the lesion center. The patient underwent successful staged excision and reconstruction. Literature review has demonstrated case reports supporting periocular hyperpigmentation; however, there has been no description of progression to periocular lentigo maligna and melanoma in a patient using bimatoprost.

Lentigo maligna melanoma mapping using reflectance confocal microscopy correlates with staged excision: A prospective study

BACKGROUND

Lentigo maligna/lentigo maligna melanoma (LM/LMM) can present with subclinical extension that may be difficult to define preoperatively and lead to incomplete excision and potential recurrence. Preliminarily studies have used reflectance confocal microscopy (RCM) to assess LM/LMM margins.

OBJECTIVE

To evaluate the correlation of LM/LMM subclinical extension defined by RCM compared with the gold standard histopathology.

METHODS

Prospective study of LM/LMM patients referred for dermatologic surgery. RCM was performed at the clinically defined initial surgical margin followed by margin-controlled staged excision with paraffin-embedded tissue, and histopathology was correlated with RCM results.

RESULTS

Seventy-two patients were included. Mean age was 66.8 years (standard deviation, 11.1; range, 38-89); 69.4% were men. Seventy of 72 lesions (97.2%) were located on the head and neck with mean largest clinical diameter of 1.3 cm (range, 0.3-5). Diagnostic accuracy for detection of residual melanoma in the tumor debulk (after biopsy) had a sensitivity of 96.7% and a specificity of 66.7% when compared with histopathology. RCM margin assessment revealed an overall agreement with final histopathology of 85.9% (κ = 0.71; P < .001).

LIMITATIONS

No RCM imaging beyond initial planned margins was performed.

CONCLUSION

RCM showed moderate to excellent overall agreement between RCM imaging of LM/LMM and histopathology of staged excision margins.

Residual melanoma in wide local excision specimens after 'complete' excision of primary cutaneous in situ and invasive melanomas

Wide local excision (WLE) to achieve adequate clearance margins is the standard initial definitive treatment for patients with biopsy-proven primary cutaneous melanoma. Residual melanoma in WLE specimens after prior complete excision-biopsy (CEB) is reported in 0-6.3% of cases. However, studies evaluating the prevalence, clinicopathological features and relevance of persistent disease in WLE specimens are limited. This study sought to determine the frequency of and clinicopathological characteristics associated with residual melanoma in WLE specimens performed after a CEB of primary cutaneous or acral melanoma (in situ or invasive) with clinically and histologically tumour-free margins, and assess its relevance. A review of the research database and pathology archives of a large Australian tertiary referral melanoma treatment centre was performed. Eligible patients were those for whom a definitive WLE was performed after CEB of a primary melanoma (in situ or invasive) with negative clinical and histological margins, between May 2013 and May 2015. All partial biopsies were excluded. Of 640 eligible patients, 510 (79.7%) had invasive melanoma and 130 (20.3%) had melanoma in situ. Residual disease was identified in 20 cases (20/640, 3.1%), of which three (15%) were melanoma in situ on CEB and 17 (85%) were invasive melanoma. On univariate analysis, the presence of residual disease in WLE specimens was associated with lentigo maligna (LM)/LM melanoma (LMM) subtype [odds ratio (OR) 10.33; 95% confidence interval (CI) 2.84-37.54; p=0.004], nodular melanoma (NM) subtype (OR 4.92; 95% CI 1.53-15.85; p=0.0076) and, for invasive tumours, higher tumour mitotic rate (mean 7.7, SD 7.51 vs 3.4, SD 4.83; OR 1.11; 95% CI 1.04-1.18; p=0.0014). Breslow thickness >4 mm was associated with a higher risk of residual disease (OR 7.30; 95% CI 1.88, 28.26; p=0.004). Cases with residual disease had primary tumours with a significantly larger diameter (median 14 mm, range 4-25) than those without residual disease (median 9 mm, range 2-60), (OR 1.07; 95% CI 1.03-1.11; p≤0.001) and were also more likely to be amelanotic (38% vs 14%), (OR 3.69; 95% CI 1.17, 11.60; p=0.026). Residual disease was associated with assessment of >3 slides of tissue (OR 6.98; 95% CI 1.54-31.62; p=0.0118) and complete blocking of the scar (OR 31.69; 95% CI 3.98-252.21; p=0.0011). Residual melanoma in WLE specimens is an infrequent occurrence. Risk factors for residual disease are LM/LMM and NM melanoma subtypes, higher mitotic rate, larger lesion diameter and amelanosis. Tumours with these features warrant more extensive pathological sampling. WLE after CEB for melanoma remains an important procedure to reduce local recurrence; however, limited pathological sampling of the WLE scar is probably appropriate for cases lacking high risk features.

Immunostained Frozen Sections Vs Traditional Permanent Paraffin Sections for Lentigo Maligna Treated With Mohs Micrographic Surgery

BACKGROUND

Mohs micrographic surgery (MMS) has risen in popularity as a management option for treating lentigo maligna (LM) because of its ability to accurately detect subclinical spread while conserving tissue. The primary concern for opponents of MMS in melanoma remains the difficulty associated with interpretation of frozen sections compared with traditional paraffin sections; this has been made easier with the advent of immunostaining.

OBJECTIVE

Our study aims to assess the concordance in clearance reporting of LM in immunostained frozen sections compared with permanent paraffin sections and hematoxylin and eosin staining.

METHODS

We conducted a retrospective analysis of 38 LM cases treated by MMS between 2017 and 2020 in Melbourne, Australia. Immunostained frozen sections were assessed by a Mohs surgeon, whereas permanent paraffin sections were assessed by an external dermatopathologist.

RESULTS

We report 86% agreement in reporting of LM in immunostained frozen sections compared with permanent paraffin sections. In 5/38 cases, permanent paraffin sections were reported as clear for LM, but the Mohs surgeon had detected positive margins, requiring further excision.

CONCLUSION

For LM treated with MMS, there is a high agreement of clearance reporting between immunostained stained frozen sections and permanent paraffin sections without immunostaining; however, immunostained frozen sections may be more sensitive.

Modified Mohs Micrographic Surgery in Lentigo Maligna Treatment: A Series of Six Cases

The surgical approach to lentigo maligna is a challenge to dermatologists, given its clinical and histopathological particularities. Staged excision with paraffin-embedded, permanent sections for histopathological evaluation of surgical margins is an effective treatment of lentigo maligna because it enables complete excision of the tumor, at the same time preserving maximum amount of healthy tissue. We report a case series of 6 patients diagnosed with lentigo maligna who underwent this procedure in our Institution and we describe the procedure we used. Complete excision of the tumors was achieved with one to three levels, with margins of excision ranging from 2 to 8 mm. There were no local recurrences at the median follow-up of 16 months, obtaining 100% cure rate with this technique. These are comparable with the margins and number of levels of excision described in previous case series reported in the literature. The technique described herein for the treatment of lentigo maligna provides excellent cure rates for this type of cutaneous malignancy notorious for its challenging management.

[Micrographic surgery of lentigo maligna 5 years later]

Lentigo maligna is an in situ melanoma which usually affects sun-damaged skin on the head and neck. In patients with lentigo maligna, the clinically visible demarcation often correlates poorly with the histopathologically confirmed demarcation. Micrograhic surgery of lentigo maligna offers certainty of the presence of clear histological margins and is at the same time tissue sparing. Because of the clear margins after micrographic surgery, this technique leads to fewer recurrences than standard excision.

Utility of teledermatopathology for intraoperative margin assessment of melanoma in situ, lentigo maligna type: A 6 year community practice experience

BACKGROUND

Achieving negative margins for melanoma in situ, lentigo maligna type can be challenging, particularly on cosmetically sensitive areas.

OBJECTIVE

To assess the utility of intraoperative frozen section margin assessment using a teledermatopathology system in the treatment of head and neck lentigo maligna.

METHODS AND MATERIALS

Over a 6 year period, 96 patients with lentigo maligna had surgical excisions. The margins were assessed intraoperatively with frozen sections prepared in the manner used in Mohs surgery. The surgeon guided the frozen section slides around the margin while a dermatopathologist assessed the margin remotely.

RESULTS

In 2/96 (2.1%) cases, the safety margin was positive (frozen sections were false negative). In 1 further case (1%) there was a recurrence of the melanoma 13 months following the excision.

CONCLUSION

The described method is effective in treating melanoma in situ, lentigo maligna type with clearance rates similar to previous studies for Mohs surgery.

In vivo and ex vivo confocal microscopy for the evaluation of surgical margins of melanoma

We report the first series of melanomas (MMs) where the surgical margins were evaluated both by ex vivo confocal microscopy (EVCM) and in vivo reflectance confocal microscopy (RCM). We evaluated the surgical margins of 42 cutaneous MMs of lentigo maligna/lentigo maligna melanoma type and 2 mucosal MMs with EVCM. Cutaneous MMs also underwent RCM mapping. Imaging results were compared with histopathology. The rate of correct identification of the tumor margins (invaded or not invaded) was 97.6% for RCM (evaluations of cutaneous MMs) and 95.5% for EVCM (evaluations of both cutaneous and mucosal MMs). Our study showed that the MM extension is visible under EVCM and that the combination of in vivo RCM and EVCM can be a new strategy for the evaluation of surgical margins of MMs.

Clinical size is a poor predictor of invasion in melanoma of the lentigo maligna type

BACKGROUND

There are no well-defined clinical factors to predict the risk of occult invasion in melanoma of the lentigo maligna type (LM) before complete histopathologic analysis.

OBJECTIVE

To evaluate whether clinical size was a predictor of invasion in LM and subclinical extension.

METHODS

Consecutive cases of LM were recorded in a prospectively maintained database from 2006 to 2019. Patient and tumor data were recorded during initial evaluation. The LM clinical area was calculated in square millimeters (length × width). All patients were treated with staged excision.

RESULTS

We included 600 patients. The mean age was 65.9 years (standard deviation, 12.3; range, 27-95 years); 62.8% (n = 377) were men. The mean LM clinical area was 128.32 mm² for in situ lesions versus 200.14 mm for invasive lesions (P = .1). Based on quantile regression, the median margin required for complete removal increased with LM clinical area.

LIMITATIONS

The study was performed in a tertiary cancer center with possible referral bias and more complex cases.

CONCLUSIONS

LM can present with variable clinical size, which may correlate with subclinical extension; however, the presence of invasion is not well estimated by LM clinical area.

Ten-year Follow-up Study of Grenz Ray Treatment for Lentigo Maligna and Early Lentigo Maligna Melanoma

Radiotherapy is often used to treat lentigo maligna. However, the long-term efficacy and safety of radiotherapy approaches have not been thoroughly evaluated. We aimed to evaluate the long-term efficacy and safety of ultrasoft X-ray/Grenz ray treatment in the patients. A total of 161 lesions from 159 patients received treatment with Grenz ray between 2005 and 2007. Follow-up of recurrence was performed 10 years after the final treatment. In the study setting, the cure rates were 97% for primary therapy with Grenz ray alone and 100% when Grenz ray was combined with partial or radical excision. The treatment is well tolerated, simple to perform, and has an excellent cosmetic outcome, with 94% of patients pleased with the results. Grenz ray is painless, effective, and safe for use when surgery is not feasible. Thus, Grenz ray can be considered as a standard treatment option for lentigo maligna.

Incompletely excised lentigo maligna melanoma is associated with unpredictable residual disease: clinical features and the emerging role of reflectance confocal microscopy

BACKGROUND

Lentigo maligna/lentigo maligna melanoma (LM/LMM) poses a treatment and surgical challenge given unpredictable subclinical extension resulting in incomplete excision.

OBJECTIVES

To describe the demographic, clinical and pathologic characteristics of incompletely excised LM/LMM. To evaluate the potential role of reflectance confocal microscopy (RCM).

PATIENTS AND METHODS

A retrospective review of a melanoma database at a tertiary cancer centre for patients referred with 'incompletely excised LM/LMM' or 'incompletely excised melanoma' between October 2006 and July 2017. We recorded clinical and pathological data and surgical margins needed to clear the residual LM/LMM. The second part consisted of a prospective cohort of patients in which RCM was performed when presenting with incompletely excised LM/LMM.

RESULTS

We included a total of 67 patients (retrospective + prospective cohort); mean age was 64.9 (standard deviation: 11.3) years and 52.2% were males. For the retrospective cohort (n = 53), the mean scar size was 3.4 cm. The average initial margins excised prior to presentation were 4.8 mm (range 3-7 mm). The average additional margin needed to clear the residual, incompletely excised LM/LMM was 7.8 mm. For the prospective cohort (n = 14), there were no differences in age, gender or size when compared to the retrospective cohort. RCM had a diagnostic accuracy of 78.6%, a sensitivity of 90.9%, a specificity of 33.3% and a positive predictive value of 83.3% for the detection of incompletely excised LM/LMM.

CONCLUSIONS

Incompletely excised LM/LMM is a poorly characterized clinical-pathological scenario that may require considerable extra margins for microscopic clearance. RCM may emerge as a valuable tool for the evaluation of patients with incompletely excised LM/LMM.

Topical Imiquimod for Management of Recurrent Lentigo Maligna Melanoma in Situ

Topical imiquimod is a medication approved for the treatment of external genital and perianal warts, actinic keratosis, and superficial basal cell carcinoma. There have also been reports of its successful use in patients with lentigo maligna melanoma in situ. An 80-year-old female patient was diagnosed with lentigo maligna melanoma in situ which was then surgically removed. After several recurrences, nonsurgical treatment using topical 5% imiquimod was introduced. At 9-month follow-up the skin was completely healed with no evidence of cancer recurrence. In select cases, topical imiquimod seems to be an effective alternative to surgical treatment of melanoma in situ (MIS). Further studies are necessary to assess the successfulness of this treatment method.

[Diagnostics and treatment of lentigo maligna melanoma in Denmark]

The incidence of maligna melanoma has doubled in Denmark over the latest 30 years. Lentigo maligna melanomas (LMM) account for 10-26% of the melanomas in head and neck. LMM most often strike people over the age of 70 years and frequently occur in sun-exposed skin areas. LMM can be difficult to diagnose, since its clinical features are similar to benign skin lesions, solar lentigo and seborrhoeic keratosis. This review presents various methods for diagnosing and treating LMM. The specific method is chosen in dialogue with the patients, and overall health is an important factor when choosing an appropriate treatment.

Comparison of surgical margins for lentigo maligna versus melanoma in situ

BACKGROUND

Multiple studies have shown a 5-mm surgical margin to be inadequate for excision of melanoma in situ. Some have suggested that a wider margin is needed only for the lentigo maligna subtype.

OBJECTIVE

To compare subclinical extension of lentigo maligna with that of melanoma in situ. The secondary objective was to investigate the effect of other factors on extent of subclinical extension.

METHODS

A prospectively collected series of noninvasive melanomas was studied. Original pathology reports were used to identify lentigo maligna and compare data for that subtype with data for the remaining melanomas in situ.

RESULTS

A total of 1506 lentigo maligna cases and 829 melanomas in situ were included. To obtain a 97% clearance rate, both lentigo maligna and melanoma in situ required a 12-mm margin on the head and neck and a 9-mm margin on the trunk and extremities. Only 79% of lentigo maligna and 83% of melanoma in situ were successfully excised with a 6-mm margin (P = .12). Local recurrence was identified in 0.26% (5 facial, 1 scalp, and 1 acral), with a mean follow-up time of 5.7 years.

LIMITATIONS

Margins less than 6 mm were not studied. The use of lentigo maligna diagnosis was not used by all dermatopathologists consistently. The degree of surrounding photodamage was not assessed.

CONCLUSION

Subclinical extension of lentigo maligna and melanoma in situ are similar. Standard surgical excision of all melanoma in situ subtypes, including lentigo maligna, should include at least 9 mm of normal-appearing skin, which is similar to the amount recommended for early invasive melanoma. Lesions on the head and neck or those with a diameter greater than 1 cm may require even wider margins and are best treated with Mohs micrographic surgery. The perception that lentigo maligna has wider subclinical extension may be related to its frequent location on the head and neck, where photodamage can camouflage the clinical border.

Clinical features and prognosis of Asian patients with acral lentiginous melanoma who have nodal nevi in their sentinel lymph node biopsy specimen

BACKGROUND

Nodal melanocytic nevi (NNs) encountered during sentinel lymph node biopsy (SLB) for malignant melanoma are usually difficult to distinguish from metastatic melanoma. However, NNs have not been well studied in acral lentiginous melanoma (ALM) in Asian populations.

OBJECTIVE

To investigate the clinical characteristics and significance of NNs in SLB specimens from patients with ALM.

METHODS

We retrospectively analyzed 84 patients with ALM who underwent SLB between June 2010 and July 2017.

RESULTS

Of the 84 patients with ALM, 9 (10.7%) had NNs in their SLB specimens. NNs were significantly more common in SLB specimens than in specimens not obtained by SLB. The presence of pre-existing melanocytic lesions was found to be associated with NNs (P < .001). The 5-year overall survival was significantly higher in patients with ALM with NNs than in patients with a positive SLB result (P = .047). Distant recurrence in patients with ALM with NNs was significantly lower than in patients a positive SLB result (P = .03).

LIMITATIONS

The small sample size, single-center study design, and retrospective nature of the study were the limitations.

CONCLUSION

In Asian populations, the prevalence of NNs in ALM is similar to that reported in Europe and the United States. The rates of distant recurrence and overall survival in patients with ALM who have NNs are similar to those of patients who do not have metastatic melanoma.

Clinical factors associated with subclinical spread of in situ melanoma

BACKGROUND

Subclinical spread of in situ melanoma occurs at a wide frequency, ranging from 12% to 71%.

OBJECTIVE

To identify clinical factors associated with subclinical spread of in situ melanoma.

METHODS

We used a retrospective, cross-sectional study of 674 consecutive in situ melanomas to examine 627 patients treated with Mohs surgery and melanoma antigen recognized by T cells 1 immunostaining. The presence of subclinical spread was correlated with clinical characteristics. Univariate and multivariate logistic regression analyses were performed to generate odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Both univariate and multivariate analyses demonstrated significantly increased odds for subclinical spread of in situ melanomas when they were located on the head or neck, at acral sites, or on the pretibial leg (OR 1.97, 95% CI 1.41-3.40); in persons with a history of prior treatment (OR 2.77, 95% CI 1.74-4.420); melanomas of preoperative size >1 cm (OR 1.74, 95% CI 1.23-2.46, P = .002); or in persons ≥60 years old (OR 1.47, 95% CI 1.01-2.13, P = .042). A count prediction model demonstrated that the risk for subclinical spread increased with the number of clinical risk factors.

LIMITATION

We used a single-site, retrospective study design.

CONCLUSION

Clarifying the risk factors for subclinical spread might help to refine triage of in situ melanomas to the appropriate surgical techniques for margin assessment prior to reconstruction.

Clinical and pathologic factors associated with subclinical spread of invasive melanoma

BACKGROUND

Indications to treat invasive melanoma with Mohs micrographic surgery (MMS) or analogous techniques with exhaustive microscopic margin assessment have not been defined.

OBJECTIVE

Identify clinical and histologic factors associated with subclinical spread of invasive melanoma.

METHODS

This retrospective, cross-sectional study evaluated 216 invasive melanomas treated with MMS and melanoma antigen recognized by T cells 1 immunostaining. Logistic regression models were used to correlate clinicopathologic risk factors with subclinical spread and construct a count prediction model.

RESULTS

Risk factors associated with subclinical spread by multivariate analysis included tumor localization on the head and neck (OR 3.28, 95% confidence interval [CI] 1.16-9.32), history of previous treatment (OR 4.18, 95% CI 1.42-12.32), age ≥65 (OR 4.45, 95% CI 1.29-15.39), and ≥1 mitoses/mm2 (OR 2.63, 95% CI 1.01-6.83). Tumor thickness and histologic subtype were not associated with subclinical spread. The probability of subclinical spread increased per number of risk factors, ranging from 9.22% (95% CI 2.57%-15.86%) with 1 factor to 80.32% (95% CI 68.13%-92.51%) with 5 factors.

LIMITATIONS

This study was conducted at a single academic institution with a small study population using a retrospective study design that was subject to potential referral bias.

CONCLUSION

Clinical and histologic factors identify invasive melanomas that are at increased risk for subclinical spread and might benefit from MMS or analogous techniques prior to reconstruction.

The use of Mohs micrographic surgery (MMS) for melanoma in situ (MIS) of the trunk and proximal extremities

BACKGROUND

Evaluation of the entire surgical margin results in high rates of complete excision, low local recurrence rates, and maximal tissue conservation. Although well recognized for melanoma of the head and neck, few studies have focused exclusively on the trunk and proximal extremities.

OBJECTIVE

We sought to evaluate the efficacy of Mohs micrographic surgery for melanoma in situ (MIS) of the trunk and proximal extremities, and determine adequate excision margins for MIS when total margin evaluation is not used.

METHODS

Long-term outcomes in 882 cases of MIS treated with Mohs micrographic surgery were analyzed and compared with historical controls. Rates of complete excision were determined for increasing surgical margin intervals.

RESULTS

One local recurrence occurred in our cohort (0.1%). Only 83% of MIS were excised with a 6-mm margin. Margins of 9 mm were needed to excise 97% of MIS, statistically equivalent to thin melanomas.

LIMITATIONS

We used a nonrandomized, single-institution, retrospective design.

CONCLUSION

Mohs micrographic surgery may cure the 17% of MIS that exceed traditional excision margins of 5 mm and is a valuable option for these patients. Surgical margins of at least 0.9 cm should be considered for MIS of the trunk and extremities when total margin evaluation is not used.

Robot-assisted video endoscopic inguinal lymphadenectomy for melanoma

Inguinal lymphadenectomy is the indicated procedure in the regional lymph node management for patients with lower limb melanoma and positive nodes. This procedure is commonly associated with surgical site complications. Video endoscopic inguinal lymphadenectomy is a minimally invasive alternative with oncological principles and lower wound-related morbidity. Incorporation of robotic surgery with optimal vision and great maneuverability would offer great advantages. A 42-year-old male patient was diagnosed with acral lentiginous melanoma and palpable inguinal nodes T2 N1 M0. The patient was scheduled for robot-assisted left inguinal video endoscopic lymphadenectomy. The working space is created using blunt-finger dissection and then extended with the endoscope by sweeping with the lens. Two 8-mm robotic trocars and a 10-mm trocar for assistant are placed. The lymphadenectomy is carried out with Maryland and scissors. The operative time was 130 min, estimated blood loss 70 ml and hospital stay 2 days. The robot-assisted inguinal video endoscopic lymphadenectomy is a safe and feasible procedure for lower limb melanoma treatment. The incorporation of the robotic system to this approach where there is a limited working space would offer advantages to the technique.

[Micrographic surgery of lentigo maligna]

Lentigo maligna is an in situ melanoma which usually affects sun-damaged skin on the head and neck. In patients with lentigo maligna, the clinically visible demarcation often correlates poorly with the histopathologically confirmed demarcation. The standard treatment for lentigo maligna is excision with at least 5 mm margins. The key disadvantage of regular excision is the lack of histological margin control, resulting in non-radical excisions and a higher risk of recurrence. Micrographic surgery is indicated for patients with lentigo maligna because this technique is tissue-sparing and it offers absolute certainty concerning the presence of clear histological margins.

Delineating margins of lentigo maligna using a hyperspectral imaging system

Lentigo maligna (LM) is an in situ form of melanoma which can progress into invasive lentigo maligna melanoma (LMM). Variations in the pigmentation and thus visibility of the tumour make assessment of lesion borders challenging. We tested hyperspectral imaging system (HIS) in in vivo preoperative delineation of LM and LMM margins. We compared lesion margins delineated by HIS with those estimated clinically, and confirmed histologically. A total of 14 LMs and 5 LMMs in 19 patients were included. HIS analysis matched the histo-pathological analysis in 18/19 (94.7%) cases while in 1/19 (5.3%) cases HIS showed lesion extension not confirmed by histopathology (false positives). Compared to clinical examination, HIS defined lesion borders more accurately in 10/19 (52.6%) of cases (wider, n = 7 or smaller, n = 3) while in 8/19 (42.1%) cases lesion borders were the same as delineated clinically as confirmed histologically. Thus, HIS is useful for the detection of subclinical LM/LMM borders.

Facial reconstruction following Mohs micrographic surgery: a report of 622 cases

BACKGROUND

Around 100 to 200 patients undergo surgical reconstruction every year at our department of plastic and reconstructive surgery after Mohs micrographic surgery for nonmelanoma skin cancer.

OBJECTIVE

The aim of this report is to provide an overview of the type of facial reconstructions performed and investigate whether we achieved increased, definitive closure rates of the defect on the day of the excision after further improving the collaboration between the involved departments.

METHODS

All patients who underwent facial reconstruction at the Department of Plastic and Reconstructive Surgery following Mohs micrographic surgery between January 2006 and January 2011 were retrospectively systematically reviewed.

RESULTS

A total of 564 patients with 622 defects were identified. The different reconstructions used per aesthetic unit are described. The number of cases in which a reconstruction was performed on the same day as the resection significantly increased from 31 to 81% (p < .001).

CONCLUSION

Facial reconstruction following Mohs micrographic surgery is challenging. The type of reconstruction used depends on the type of defect and patient characteristics. A structured multidisciplinary approach improves the process from defect to reconstruction and can facilitate referrals.

Incidence of lentigo maligna in Olmsted County, Minnesota, 1970 to 2007

BACKGROUND

The incidence of lentigo maligna (LM) may be increasing, but no population-based epidemiologic studies have been performed to our knowledge.

OBJECTIVE

We sought to determine the incidence of LM in Olmsted County, Minnesota, along with overall and recurrence-free survival.

METHODS

Using the Rochester Epidemiology Project, we identified all adult residents of Olmsted County, Minnesota, with a first lifetime diagnosis of LM between 1970 and 2007. Medical records were reviewed to determine demographic, clinical, and surgical data, and incidence and survival were calculated.

RESULTS

Among 145 patients identified, median (range) age at diagnosis of LM was 70 (33-97) years. Treatment changed over time, with Mohs micrographic surgery becoming available after 1986. No patients died of LM; 5 had local recurrence. Estimated local recurrence-free survival at 5, 10, 15, and 20 years after diagnosis was 98%, 96%, 92%, and 92%, respectively. Overall age- and sex-adjusted incidence of LM among adults was 6.3 per 100,000 person-years, increasing from 2.2 between 1970 and 1989 to 13.7 between 2004 and 2007.

LIMITATIONS

Retrospective study design and homogeneous population are limitations.

CONCLUSION

The incidence of LM increased significantly among residents of Olmsted County, Minnesota, over an extended time frame, with incidence being significantly higher among men than women and increasing with age.

Surgical and histologic pitfalls in the management of lentigo maligna melanoma

Lentigo maligna melanoma (LMM) is a malignancy with increasing incidence, accounting for about 4% to 15% of all melanomas. Lentigo maligna (LM) is LMM in situ, usually presenting an irregular tan colored or brownish pigmented macular lesion persisting for years on chronically sun-exposed skin. Left untreated, LM may evolve into invasive form of LMM. Histologic evaluation of LM/LMM can be difficult due to widespread atypical melanocytes that are present in the area chronically sun damaged skin. It has been shown that chronically sun-damaged non-lesional skin can display some atypical features even in the absence of a melanocytic neoplasm. It is important for dermatopathologists to be aware of these findings so that such features are interpreted appropriately when making a histological assessment that may ultimately influence therapy and outcome. LMM is characterized by significant subclinical lesion extension which makes the treatment another challenge. Nowadays, a variety of therapeutic options are available in the treatment of LMM. Surgery remains the mainstay of LMM therapy, however the treatment of LM remains controversial subject in the literature. Non-surgical treatment modalities for LM include: destructive procedures such radiotherapy, cryotherapy, curettage, laser, electro-destruction and immunotherapy with the topical application of 5% imiquimod cream. These treatment options should be considered for a subset of patients with LM, especially in elderly patients with extensive or unresectable disease in difficult areas on the face or, as a second-line therapy if surgery is contraindicated. Surgical options include simple excision and margin-control techniques such as staged excision and Mohs micrographic surgery.In this article, authors are reviewing the latest diagnostic and therapeutic advances in the management of LMM.

Lentigines, laser, and melanoma: a case series and discussion

Solar lentigines are considered one of the earliest signs of photoaging and are an extremely common cosmetic complaint. Successful removal of these lesions can be achieved with laser and non-laser light sources, and is one of the most frequently performed cosmetic procedures in laser centers. Distinguishing a benign lentigo from other pigmented lesions can sometimes be challenging, even for a trained dermatologist. We report a series of three patients who presented to our laser center within 2 months of one another for cosmetic removal of pigmented lesions that were found to be melanoma. One patient was referred by another dermatologist, one by a physician family member, and the other presented on his own. These cases highlight the need for careful evaluation of pigmented lesions prior to laser treatment, regardless of the source of the referral. In this article, we will review the diagnostic and treatment differences between lentigines and their malignant counterparts, and examine the role of laser in both.

Grenz ray treatment of lentigo maligna and early lentigo maligna melanoma

BACKGROUND

Lentigo maligna (LM) is the in situ phase of lentigo maligna melanoma (LMM). A wide variety of modalities has been used to manage LM, including conventional surgery, staged excision, Mohs micrographic surgery, cryotherapy, radiotherapy, laser therapy, and, recently, imiquimod.

OBJECTIVES

Soft x-radiation is an accepted treatment for LM/LMM. The aim of the present study was to evaluate the efficacy and safety of ultra-soft x-ray/grenz-ray (GR) treatment in patients with LM and early LMM.

METHODS

Five hundred ninety-three patients were treated with GR (primary therapy, n = 350; partial excision followed by GR, n = 71; radical excision followed by GR as recurrence-prophylactic treatment, n = 172) at the Department of Dermatology, Karolinska University Hospital, Stockholm, Sweden between 1990 and 2009. The treatment was given twice a week over 3 consecutive weeks in total doses of 100 to 160 Gy. Dosage depended on the stage of LM and the depth of periadnexal atypical melanocytic extension in histologically examined materials before treatment. Four hundred twenty-five patients have been followed up for at least 2 years; of these, 241 for 5 years.

RESULTS

Overall, 520 of 593 patients (88%) showed complete clearance after one fractionated treatment. Residual lesions were seen in 15 patients, and 58 relapsed, 53 of whom (72%) within 2 years.

LIMITATION

Woods light examination was not used in the clinical diagnosis of lentigo maligna.

CONCLUSIONS

GR is an efficient and safe treatment in LM and early LMM when administered according to the recommendations presented herein. Moreover, GR offers an excellent cosmetic result.

Porcine xenograft biosynthetic wound dressings for the management of postoperative Mohs wounds

Cadaveric allografts and a large variety of other biologic dressings have been reported as being useful for the postoperative management of Mohs micrographic surgery (MMS) wounds. Although the use of porcine xenografts for the immediate postoperative management of these wounds is known, their use has not been detailed in the dermatology literature. A case series of 15 consecutive Mohs micrographic surgery patients (mean age = 74.9 years, range = 49 to 89 years) with wounds initially managed with porcine xenografts is described. Porcine xenografts were useful in a variety of clinical settings following MMS. These included: (1) wound management when tumor margins were indeterminate pending additional dermatopathology studies and (2) wound management when there are issues such as through and through nasal defects involving the mucosa, large wound depth, exposed cartilage and or bone, or patient medical comorbidities that delay or prevent plans for immediate wound reconstruction. Future controlled studies of biologic dressings are needed to determine which options are best for micrographic surgery wounds. Comparisons should also include the traditional option of second intention healing without biologic dressings.

Staged margin control techniques for surgical excision of lentigo maligna

For melanoma in situ (MIS) arising in chronically photodamaged skin (a.k.a. lentigo maligna, LM), the preferred treatment remains surgical excision. Yet, the standard 5-mm margins of excision recommended for other subtypes of MIS have proven insufficient for LM, due to the its indistinct borders. In this report, authors review specialized surgical techniques for the treatment of LM that focus on meticulous assessment of peripheral margins prior to closure (staged margin control) conducted with analysis of either frozen or permanent histologic sections. Techniques utilizing permanent sections include variations of the ''square'', ''perimeter'', and ''contoured'' excisions, and recurrence rates with these techniques are reportedly low based on short-term follow-up. Similarly, Mohs micrographic surgery (MMS) has been reported to be effective in LM, with recurrence rates generally less than 1% over three-five years of follow-up. In order to simplify margin assessment for MMS, many investigators have begun to rely on intraoperative immunohistochemistry (IHC) to identify melanocytes in frozen sections, and MART-1 is surrently the preferred immunostain for this purpose. Other methods of IHC are currently under investigation. Regardless, surgical methods that employ this degree of margin assessment offer superior cure rates compared to standard excision, and should be seriously considered when encountering patients with LM. Total peripheral margin assessment using staged excisions and analysis of permanent sections appears to be a simple and effective alternative to MMS, especially for institutions that prefer examination of permanent sections to frozen sections.

Lentigo maligna occurring in a patient with the past history of laser therapy

A 70-year-old Japanese woman visited our clinic with a pigmented patch on her face from her upper lip to under her nose following laser therapy 15 years ago. Physical examination revealed an asymmetrical dark brown macule with a clear border along with irregular black dots measuring 20 mm. A biopsy specimen showed some irregular-sized atypical melanocytes with deep-colored nuclei on staining. There were observed on the basal layer and a few of them in the prickle-cell layer only in the epidermis. We diagnosed this case as lentigo maligna (LM). Total resection and reconstruction with the Abbe flap were carried out. We searched previous literature for reports on laser therapies resulting in LM and determined the following: (1) there were no reports indicating that laser therapy is one of the causes of LM, (2) judging from invalidity of treatment or recurrence of the condition, laser therapies were considered ineffective for LM treatment, and (3) the numbers of patients undergoing laser therapies, who were not diagnosed with LM, were increasing.