Dermoscopic and histopathological findings of polymorphous vessels in amelanotic cutaneous metastasis of pigmented cutaneous melanoma

Neurosarcomatous amelanotic transformation of malignant melanoma presenting as malignant periopheral nerve sheath tumor: Rare case report

RATIONALE

Malignant melanoma (MM) is notorious for its remarkable morphological variation and aberrant histopathological patterns. In addition, Malignant Periopheral Nerve Sheath Tumor (MPNST) is an uncommon but aggressive soft tissue sarcoma. Because of the common embryological origin of melanocytes and Schwann cells in the neural crest, discriminating between a particular type of MM and MPNST can be difficult, particularly when they are amelanotic. Our goal is to increase awareness among clinicians of the rare variations of MM and the importance of medical history in improving the accuracy of the final clinical diagnosis.

PATIENT CONCERNS

A 68-year-old man was admitted to the hospital due to pain in his right ankle, which had persisted for 8 months, along with swelling for 4 months. Medical history revealed delayed healing of right plantar for 5 years after a traumatic injury.

DIAGNOSES

The ankle mass was initially diagnosed as MPNST through biopsy. After reviewing the patient's medical history and receiving the final pathological report following amputation, we have revised the diagnosis to metastatic amelanotic desmoplastic melanoma in the ankle part and lentigo maligna melanoma in the plantar part. This is due to both lesions displaying positive markers or mutated genes in immunohistology and Gene Mutation Detection, indicating homology between the 2 tumors.

INTERVENTIONS

Due to the malignant characteristics of the tumor and the patient's wishes, amputation of the right lower leg was carried out.

OUTCOMES

Subsequently, the patient was treated with interferon-γ and immunosuppressant PD-1 inhibitor, and survived for 1 year after amputation.

LESSONS

Clinical data, immunohistochemisty biomarkers and genes detection results can serve as valuable evidence for pathologists and clinicians in identifying the disease process. Collaborative efforts between clinicians and scientists are crucial in order to identify specific markers that can effectively differentiate between the 2 tumors, thereby enhancing the conclusiveness of the diagnosis.

Dermoscopy of cutaneous melanoma metastases: A color-based pattern classification

Dermoscopic studies about cutaneous metastases of malignant melanoma (CMMM) are few. Our objective was to analyze the dermoscopic features of CMMM and propose a new dermoscopic pattern classification based on color pigmentation and some specific dermoscopic features. A retrospective evaluation of 150 dermoscopic images of CMMM taken from 40 patients was performed. One hundred CMMM images were individually evaluated by six dermatologists in order to classify them according to four dermoscopic patterns: (i) blue pattern; (ii) pink pattern; (iii) brown pattern; and (iv) mixed pattern. One hundred and fifty dermoscopic images including 50 CMMM and 100 benign lesions were evaluated by five dermatologists to calculate the accuracy of these patterns in the recognition of CMMM. An intra- and interobserver reproducibility agreement study between all different dermoscopic pattern classifications was performed. Seventy-five percent of our cases of CMMM showed a monochromatic pattern. Light brown pigmented halo, peripheral gray spots and polymorphic atypical vessels were the most significant focal dermoscopic structures. The reproducibility of the color-based dermoscopic pattern classification was superior to previous dermoscopic pattern classification. In summary, a dermoscopic pattern classification based on color pigmentation and some specific dermoscopic features may be useful in recognizing early cutaneous melanoma metastasis. Multicentric studies are recommended in order to lower the impact of interobserver variability.

Morphological classification of melanoma metastasis with reflectance confocal microscopy

BACKGROUND

Cutaneous malignant melanoma metastases differential diagnosis is challenging, as clinical and dermoscopic features can simulate primary melanoma or other benign or malignant skin neoplasms, and in-vivo reflectance confocal microscopy could assist. Our aim was to identify specific reflectance confocal microscopy features for cutaneous malignant melanoma metastases, and epidermal and dermal involvement.

METHODS

A retrospective, multicentre observational study of lesions with proven cutaneous malignant melanoma metastases diagnosis between January 2005 and December 2016. Lesions were retrospectively assessed according to morphological features observed at reflectance confocal microscopy. Potential homogeneous subgroups of epidermal or dermal involvement were investigated with cluster analysis.

RESULTS

Cutaneous malignant melanoma metastases (51 lesions in 29 patients) exhibited different frequencies of features according to metastasis dermoscopy patterns. Lesions classified at dermoscopy with nevus-like globular and non-globular patterns were more likely to be epidermotropic, showing characteristics of epidermal and dermal involvement at reflectance confocal microscopy. Other dermoscopy pattern classifications were more likely to be dermotropic, showing characteristics od dermal involvement at reflectance confocal microscopy. Distinguishing features at reflectance confocal microscopy included irregular (78%) and altered (63%) epidermis, pagetoid infiltration (51%), disarranged junctional architecture (63%), non-edged papillae (76%), dense and sparse, and cerebriform nests in the upper dermis (74%), and vascularity (51%). Cluster analysis identified three groups, which were retrospectively correlated with histopathological diagnoses of dermotropic and epidermotropic diagnoses (P < 0.001). The third cluster represents lesions with deep dermis morphological changes, which were too deep for evaluation with reflectance confocal microscopy.

CONCLUSIONS

Specific reflectance confocal microscopy features of cutaneous malignant melanoma metastases for correct diagnosis, and subtype diagnosis, seem achievable in most cases where morphological alterations are located above the deep dermis.

BRAF and KIT somatic mutations are present in amelanotic melanoma

The genotypic profile of rare amelanotic melanomas (AMs) has been poorly investigated, thus preventing either an accurate identification as a distinctive melanoma subtype or therapy stratification. Here, we investigated the presence of the BRAF(V600E) mutation by real-time quantitative PCR and KIT mutations (exons 11 and 17) by sequencing analysis in 33 AMs. AMs included 'truly' amelanotic lesions (n = 19), with no melanin pigmentation upon dermoscopic inspection and hypomelanotic lesions (n = 14), by definition partially pigmented lesions showing a melanin pigmentation area of less than 25% of the total surface area. The frequency of the BRAF(V600E) mutation was 70.3% in the 33 cases, a percentage that increased to 89% when only the subgroup of thin melanomas (≤ 1 mm in thickness, n = 9) was considered. KIT mutations were found in 12.1% of AMs, all of which developed in nonacral sites. The identification of a relatively high frequency of BRAF(V600E) and KIT mutations in AMs may have important consequences for implementation of the novel targeted therapies now available to treat this life-threatening disease.

Dermoscopic patterns of melanoma metastases: interobserver consistency and accuracy for metastasis recognition

BACKGROUND

Cutaneous metastases of malignant melanoma (CMMM) can be confused with other skin lesions. Dermoscopy could be helpful in the differential diagnosis.

OBJECTIVES

To describe distinctive dermoscopic patterns that are reproducible and accurate in the identification of CMMM.

METHODS

A retrospective study of 146 dermoscopic images of CMMM from 42 patients attending a melanoma unit between 2002 and 2009 was performed. Firstly, two investigators established six dermoscopic patterns for CMMM. The correlation of 73 dermoscopic images with their distinctive patterns was assessed by four independent dermatologists to evaluate the reproducibility in the identification of the patterns. Finally, 163 dermoscopic images, including CMMM and nonmetastatic lesions, were evaluated by the same four dermatologists to calculate the accuracy of the patterns in the recognition of CMMM.

RESULTS

Five CMMM dermoscopic patterns had a good interobserver agreement (blue naevus-like, naevus-like, angioma-like, vascular and unspecific). When CMMM were classified according to these patterns, correlation between the investigators and the four dermatologists ranged from κ = 0.56 to κ = 0.7. In total, 71 CMMM, 16 angiomas, 22 blue naevi, 15 malignant melanomas, 11 seborrhoeic keratoses, 15 melanocytic naevi with a globular pattern and 13 pink lesions with a vascular pattern were evaluated according to the previously described CMMM dermoscopy patterns, showing an overall sensitivity of 67.9% (range 54.9-76%) and a specificity of 79.9% (range 68.5-93.5%) for the diagnosis of CMMM.

CONCLUSIONS

Five dermoscopic patterns of CMMM with good interobserver agreement obtained a high sensitivity and specificity in the diagnosis of metastasis, with the accuracy varying according to the experience of the observer.

When not to treat cutaneous vascular lesions with the pulsed dye laser

The availability of effective laser treatment for cutaneous vascular lesions has risen dramatically in recent years. At the same time, there has been a proliferation of laser providers with varying amounts of training-both medical and nonmedical. We report a series of four cases where patients presented for cosmetic evaluation of vascular lesions and were discovered to have more significant pathologic disease. In presenting these cases, we hope to illuminate a basic differential diagnosis that exists for cutaneous vascular lesions and remind healthcare providers that not all "cosmetic" concerns are benign in origin. There is a differential diagnosis that exists for cutaneous vascular lesions that is worth reviewing, and it should be considered in all patients presenting for laser treatment.