Evaluation of hyperpigmentation in melanomas and melanocytic nevi scars through confocal microscopy

Introduction: In vivo confocal microscopy is an auxiliary non-invasive diagnostic method used in the diagnosis of hyperpigmented lesions in scars. Objectives: To evaluate hyperpigmentation in the scars of benign and malignant melanocytic lesions through confocal microscopy examination. Methods: Clinical, dermoscopic, and confocal microscopy images of fourteen patients with hyperpigmentation in adequately treated melanoma scars and in excised melanocytic nevi, were evaluated. Results: Among the eight patients with hyperpigmentation in melanoma scars, four showed no suspicious structures after confocal microscopy examination and four showed suspicious structures. Among the six patients with hyperpigmentation in areas where melanocytic nevi had been excised, three had atypical structures, such as dendritic cells and non demarcated papillae. Patients with suspicious structures underwent histological examination, with one case of hyperpigmentation in a lentigo maligna scar evidencing recurrence. Conclusions: The examination method allowed for the avoiding of biopsy in confirming the diagnosis in six of the fourteen patients. The finding of cells with dendritic or pagetoid pattern in the confocal microscopy examination means a diagnostic challenge, for it can indicate melanocytes or Langerhans cells in the spinous layer. Therefore, lesions that have such structures must be removed for histology and differential diagnosis.

Keywords: MELANOMA, NEVUS, DERMOSCOPY, CONFOCAL MICROSCOPY.