Lentigo maligna - anatomic location as a potential risk factor for recurrences after non-surgical treatment

Topical Calcipotriol Plus Imiquimod Immunotherapy for Nonkeratinocyte Skin Cancers

Nonkeratinocyte cutaneous malignancies, including breast cancer cutaneous metastasis and melanoma in situ, are often poor surgical candidates. Imiquimod (IMQ), a toll-like receptor 7 agonist that activates innate immunity in the skin, is used to treat these cutaneous malignancies. However, IMQ's modest effect on the activation of adaptive immunity limits its efficacy as a monotherapy. In this study, we demonstrate that topical TSLP cytokine inducers-calcipotriol and retinoic acid-synergize with IMQ to activate CD4+ T-cell immunity against nonkeratinocyte cutaneous malignancies. Topical calcipotriol plus IMQ treatment reduced breast tumor growth compared with calcipotriol or IMQ alone (P < 0.0001). Calcipotriol plus IMQ-mediated tumor suppression was associated with significant infiltration of CD4+ effector T cells in the tumor microenvironment. Notably, topical calcipotriol plus IMQ immunotherapy enabled immune checkpoint blockade therapy to effectively control immunologically cold breast tumors, which was associated with induction of CD4+ T-cell immunity. Topical treatment with calcipotriol plus IMQ and retinoic acid plus IMQ also blocked subcutaneous melanoma growth. These findings highlight the synergistic effect of topical TSLP induction in combination with innate immune cell activation as an effective immunotherapy for malignancies affecting the skin.

Pigmented lesion on the face: which is the chance of being melanoma using reflectance confocal microscopy features?

Facial melanoma presents itself as a brownish macula, being difficult to differentiate it from benign pigmented lesions of the face on clinical examination. Reflectance confocal microscopy (RCM) assists in diagnosing facial lesions in which dermoscopy has limitations, allowing to increase the diagnostic accuracy. The study aimed to analyze the RCM features of pigmented isolated lesions of the face for diagnosing melanoma. Also, we sought to establish the chance of a pigmented lesion on the face being a melanoma using RCM criteria. In this retrospective and prospective study, 105 clinical pigmented lesions on the face underwent RCM, and cytoarchitectural features in the epidermis, the dermo-epidermal junction (DEJ), and dermis were described. For statistical analysis, the exact chi-square test was applied to the RCM criteria. The odds ratio was estimated using univariate logistic regression. Finally, we used the multiple logistic regression method for creating a nomogram to predict the chance of a lesion being a melanoma. After univariate and multivariate logistic regression, atypical round nucleated cells within the epidermis, pagetoid spread, and follicular dendritic cells presented as statistically significant features. Then, a complex nomogram was created to give the chance of a pigmented lesion on the face being a melanoma. The presence of these three features resulted in a 98% probability for melanoma. This study allowed to estimate the diagnosis of melanoma on the face, using RCM, practicable and feasible in the daily routine, through the presence of some RCM nomogram criteria.

The use of 2940-nm ER:YAG laser for the treatment of lentigo maligna

OBJECTIVES

Lentigo maligna is a common in situ malignancy in elderly patients, with a low risk of progression to an invasive tumor. Surgical treatment may be complicated or refused. Non-surgical treatment options (such as lasers) may therefore be needed.

PATIENTS AND METHODS

We report on 17 patients treated with a 2940-nm Er:YAG (erbium-doped yttrium aluminum) laser for histopathologically confirmed lentigo maligna. The lesions were ablated with a 5 mm margin of adjacent skin under local anesthesia with a 3.5 mm overlapping spot, energy density of 6.5 J/cm² and a repetition rate of 5 Hz. If clinically visible pigmentation was seen in the ablated area during the following three months, the lesion was re-treated. All patients were followed up for residual or recurrent tumors.

RESULTS

We achieved clinical clearance in all 17 patients. There were three recurrences during the follow-up period (9, 30 and 36 months after laser therapy). All patients were satisfied with the treatment course and cosmetic outcome. The mean follow-up duration was 28 months.

CONCLUSIONS

Laser ablation is an interesting alternative method for treatment of lentigo maligna. It can be used for selected cases where surgery is contraindicated, complicated or declined by the patient.

Follicular involvement is frequent in lentigo maligna: Implications for treatment

BACKGROUND

Follicular involvement of lentigo maligna (LM) is considered a histopathologic hallmark, but its prevalence and characteristics have not been well defined. The depth of intrafollicular extension by neoplastic melanocytes may have clinical importance in the treatment of LM.

OBJECTIVE

To describe the prevalence and features of follicular involvement in LM, including depth of follicular growth by melanocytes.

METHODS

A single-center retrospective study of 100 consecutive cases of surgically excised LM that was treated from 2013 to 2015. The slide review for cases with residual LM on the debulk specimen was performed by a dermatologic surgeon and dermatopathologist to characterize follicular involvement.

RESULTS

Of 100 specimens, 72 met the inclusion criteria for histopathologic evaluation. Follicular involvement was seen in 95.8% of specimens (95% confidence interval, 88.3%-99.1%), with a mean of 68% of follicles involved in a single specimen. The mean depth of intrafollicular growth by lesional melanocytes was 0.45 mm (standard deviation, 0.23; range, 0.1-1.1 mm). Tumor cells were confined to the infundibular portion of the hair follicle in 60.9% of specimens.

CONCLUSION

Superficial follicular involvement is a ubiquitous finding in LM. When treatment options for LM with a depth-dependent modality aiming for tumor clearance are being considered, mean and maximum depths of involvement should be taken into consideration.

Lentigo maligna: diagnosis and treatment

Lentigo maligna (LM) is an in situ subtype of melanoma, clinically presenting as a pigmented, asymmetric macule that originates mostly on the head and neck and spreads slowly. The diagnosis may be challenging both for clinicians and pathologists. Dermatoscopy and reflectance confocal microscopy represent a useful tool in the differentiation of LM from other pigmented lesions, such as pigmented actinic keratosis, solar lentigines, seborrheic keratosis and lichen planus-like keratosis. Moreover, those non-invasive diagnostic technique may be crucial in the selection of optimal biopsy sites in equivocal lesions, in pre-surgical mapping and in evaluating and monitoring response to non-surgical treatments. Histologic examination remains the gold standard for the diagnosis of LM, showing a lentiginous proliferation of basal atypical melanocytes on a severe sun-damaged skin. The management of LM is constantly evolving. Treatments include surgery (the first choice, when available), radiotherapy and imiquimod cream (in patients not candidates to surgery). Many other possible treatments for LM have been tested, but they are not yet supported by strong evidences. We collected current guidelines and PubMed available reviews, studies and case-reports in order to make an overview on diagnosis and treatment of LM.