Dedifferentiated Melanoma: A Diagnostic Histological Pitfall-Review of the Literature with Case Presentation.

Gerardo Cazzato,Gennaro Cormio,Francesca Arezzo,Vera Loizzi,Paolo Romita,Leonardo Resta,Caterina Foti,Anna Colagrande,Roberta Rossi,Antonietta Cimmino,Sara Sablone,Aurora Demarco,Lucia Lospalluti,Giuseppe Ingravallo

doi:10.3390/dermatopathology8040051

Gerardo Cazzato, Gennaro Cormio + Show 12 more

Open Access

https://doi.org/10.3390/dermatopathology8040051

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Abstract

Dedifferentiated melanoma is a particular form of malignant melanoma with a progressive worsening of the patient’s clinical outcome. It is well known that melanoma can assume different histo-morphological patterns, to which specific genetic signatures correspond, sometimes but not always. In this review we address the diagnostic difficulties in correctly recognizing this entity, discuss the major differential diagnoses of interest to the dermatopathologist, and conduct a review of the literature with particular attention and emphasis on the latest molecular discoveries regarding the dedifferentiation/undifferentiation mechanism and more advanced therapeutic approaches.

Highlights

This peculiarity constitutes the basic reason why the routine dermatopathologist must always resort to adequate immunohistochemical markers to exclude or confirm the diagnosis of malignant melanoma [1,2]
The clinical and histopathological difficulty in recognizing and correctly diagnosing this entity has already been previously reported, only in recent years has the advent of molecular biology and generation sequences (NGS) contributed, in a fundamental way, to a better understanding of the dedifferentiated phenotype
We present a case of dedifferentiated melanoma, we move between the bridle of differential diagnosis as we deal with “real life”, we conduct a review of the few cases reported in literature so far and, we focus on the molecular characteristics of their own of this phenotype with particular attention to modern therapeutic treatments

Summary

Introduction

Melanoma has always been considered as “the great mime” for its intrinsic ability to disguise itself in different guises and imitate other types of neoplastic and non-neoplastic lesions [1]. This peculiarity constitutes the basic reason why the routine dermatopathologist must always resort to adequate immunohistochemical markers to exclude or confirm the diagnosis of malignant melanoma [1,2]. We present a case of dedifferentiated melanoma, we move between the bridle of differential diagnosis as we deal with “real life”, we conduct a review of the few cases reported in literature so far and, we focus on the molecular characteristics of their own of this phenotype with particular attention to modern therapeutic treatments

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