Imaging of abdominal manifestations of melanoma.

Despite an increasing incidence of melanoma in this country, innovative new therapies are allowing patients to receive aggressive experimental treatments. Diagnostic imaging remains crucial for tumor staging and for follow-up of patients being treated with these protocols. Because metastases occur in the abdomen and pelvis in approximately 60% of patients, it is important to accurately identify all sites of tumor spread. A variety of imaging techniques are used to image these patients, with CT currently being used for staging purposes and to guide diagnostic biopsies. Other imaging techniques, such as MR, ultrasound, and fluoroscopy, are currently reserved for investigating specific complications of melanoma, such as vascular invasion, hemorrhage from a tumor, and small bowel involvement, including intussusception. Recently, whole body positron emission tomography (PET) imaging using 2-deoxy-2-fluoro-D-glucose (FDG) has been shown to be highly accurate in assessing patients with metastatic malignant melanoma. This review illustrates the spectrum of manifestations of metastatic melanoma throughout the abdomen and pelvis, including solid organ, hollow lumen, and retroperitoneal involvement, and demonstrates some of the typical and atypical manifestations that may be identified.