Assessment of the clinical and morphological characteristics of visceral melanoma metastases and primary extracutaneous melanomas.

AIM: This study aimed to assess the clinical and morphological characteristics of patients with visceral melanoma metastases and primary extracutaneous melanomas. PATIENTS, MATERIALS AND METHODS: We performed a retrospective study on patients with visceral melanoma metastases and primary extracutaneous melanomas, diagnosed in two pathology departments. RESULTS: We identified 50 cases of visceral metastases and eight cases of primary extracutaneous melanomas. A percentage of 56% of the distant metastases involved the brain, 28% were localized in the digestive tract (stomach, small bowel, colon, liver, cystic duct), 16% involved the lung, spleen, adrenal gland, peritoneum, urinary bladder and bone. In 34% of the cases, the metastases were diagnosed prior to the primary melanoma. A percentage of 62.5% of primary extracutaneous melanomas were ocular melanomas, 25% were anal mucosa melanomas and one case (12.5%) involved the penile glans. Statistical analysis showed that distant melanoma metastases were more frequently diagnosed in the seventh decade (p<0.0001), and a higher percentage of patients lived in urban areas (p=0.001). The majority of the primary cutaneous melanomas associated with brain metastases were located on the trunk (p=0.0565). The brain metastases were more frequently diagnosed in males (64%; p=0.0604). CONCLUSIONS: The brain is the most frequent organ involved by distant melanoma metastases, followed by the digestive tract. It is important to be aware of the least common metastatic locations such as cystic duct, urinary bladder, adrenal gland, spleen and peritoneum, in order to avoid misdiagnosis.