Atypical Pigment Nevus on the Border with the Melanoma-Case Report and Literature Review

Introduction:The work aims to illustrate a differential diagnosis between an atypical melanocytic nevus and melanoma at the dermatological level, thoraco-abdominal.The etiology of blue nevus includes the genetic factor (heredity) but in this case report, the patient diagnosed with the blue nevus don`t had other family members with this condition.Because the diagnosis of atypical nevus is predominantly made by histopathology, was chosen to describe the characteristics of skin lesion from a clinical, macroscopic and microscopic point of view.Case presentation: An asymptomatic 70-year-old man, presented himself in the dermatology office from the hospital outpatient clinic, for the dermatoscopy examination of multiple benign keratoses, of different dimensions at the level of the dorsal thorax and abdominal-paravertebral. Results:In the dermatoscopy exam, the appearance of atypical pigment nevus means a change in color, light infiltration or small nodule, with an irregular border, poorly defined.Immunohistochemical, exam, (IHC), confirmation of the diagnosis of blue nevus was made by performing the expression of the Melan-A, (Confirm anti-Mart-1/Mouse Monoclonal Antibodies), which was positive in melanocytic proliferation, (dermal) and the protein, (pKi67), as a prognostic marker in cancer, being positive in very rare tumor nuclei in percentage <1% with P16, (CIN-tec p16 histology). Conclusions:The Histopathological examination and Immunohistochemical, exam, (IHC), highlight aggregations of atypical melanocytic cells, without monstrosities and multiple mitoses that break the basement membrane, in contrast to the aggressiveness of malignant melanoma.