Assessment of Risk Factors Correlated with Satellites and In-Transit Metastases in Primary Cutaneous Melanomas

Background and Objectives: This study aimed to identify the risk factors of primary cutaneous melanomas associated with microsatellites, satellites, and in-transit metastases. Materials and Methods: We performed a retrospective study on patients diagnosed with invasive primary cutaneous melanomas in two pathology departments. The cases were distributed into two groups, comparing the clinical–pathological features of cases that presented microsatellites, satellites, and in-transit metastases with cases that did not present microsatellites, satellites, and in-transit metastases. Results: From the total number of primary invasive cutaneous melanomas diagnosed (n = 204), 22% presented microsatellites, satellites, and in-transit metastases (n = 46). The presence of microsatellites, satellites, and in-transit metastases was strongly correlated with a Breslow index > 4 mm, a Clark level of IV or V, and a pT3 or pT4 pathological stage (p < 0.0001). Those cases were also associated with lymphovascular invasion (p = 0.0013), ulceration of the primary melanoma (p = 0.0037), and an increased mitotic rate (p = 0.0078). The presence of microsatellites, satellites, and in-transit metastases is associated with higher rates of lymph node metastases (p = 0.0006) and recurrence (p = 0.0282). Conclusions: The most important risk factors associated with microsatellites, satellites, and in-transit metastases are represented by a Breslow index > 4 mm, a Clark level of IV or V, and an advanced pathological stage.