Cutaneous melanoma metastases: Clinical and dermoscopic findings

About 2%-20% of melanoma patients will develop cutaneous melanoma metastases (CMM). Their clinical diagnosis still remains challenging because of the variation of clinical and dermoscopic characteristics. Until today, few studies exist concerning the dermoscopic image of CMM but no one has focused on its possible association with clinicopathological melanoma characteristics.

Between 2002 and 2019, 42 patients diagnosed with melanoma at Andreas Syggros Hospital developed CMM. We studied the dermoscopic presentation of these metastases and its possible association with the clinical and histologic characteristics of the underlying melanoma.

There were 20 male and 22 female patients with a mean age of 64.02 years. Nineteen patients developed satellites and 23 in transit metastases. Mean Breslow index was estimated at 2.93 mm and ulceration was observed in half of the tumours (50%). Almost half of the patients developed cutaneous metastases on the lower limbs (45.24%). We identified 5 dermoscopic patterns of CMM: saccular, amelanotic, homogenous, vascular and polymorphic. Homogenous (30.95%) and amelanotic (28.57%) were the most common patterns. Homogenous pattern was the most common in satellite metastases while amelanotic was mostly observed in in-transit metastases. Homogenous pattern was more frequent among superficial spreading melanomas. Patients with thin (<1 mm) and medium depth (1-2 mm) melanomas mostly developed metastases with saccular pattern. Vascular pattern was only present in metastases of tumours with Breslow index 2-4 mm. Homogenous and amelanotic were the only patterns found in tumours with Breslow index >4 mm.

We observed that vascular structures were more frequent in metastases of deeper tumours while nevus-like structures were more common in metastases of thinner tumours. CMM occasionally may constitute the first clinical sign of melanoma disease. Therefore, it is important for clinicians to recognize their dermoscopic patterns which seem to be associated with some of the clinical and histological characteristics of cutaneous melanomas.