Case Author(s): Lester Johnson, M.D., Ph.D. and Barry A. Siegel, M.D. , 06/07/00 . Rating: #D2, #Q4

Diagnosis: Metastatic malignant melanoma

Brief history:

66-year-old woman with a history of malignant melanoma

Images:

An anterior FDG-PET projection image is shown

View main image(pt) in a separate image viewer

View second image(pt). Serial coronal FDG-PET images are shown

View third image(ct). An abdominal CT image at the level of the stomach is shown

View fourth image(ct). An abdominal CT image through the level of the duodenum is shown

Full history/Diagnosis is available below

Diagnosis: Metastatic malignant melanoma

Full history:

This 66-year-old woman presented with abdominal pain. She underwent endoscopy and biopsy which revealed malignant melanoma involving the stomach and duodenum. The site of the primary melanoma remains unknown. PET imaging was requested to evaluate the extent of disease.

Radiopharmaceutical:

14.0 mCi F-18 fluorodeoxyglucose (FDG) i.v.

Findings:

There are inumerable foci of abnormally increased metabolic activity in the chest, abdomen and pelvis. Some of these, most notably those in the stomach and duodenum, correlate with soft tissue masses and nodularity also seen on the CT images. These findings are consistent with widespread metastatic malignant melanoma.

Discussion:

FDG-PET imaging has excellent sensitivity for metastatic melanoma, which tends to be a high-grade, aggressive malignancy charactized by high metabolic activity and, therefore, high FDG uptake. FDG-PET is more sensitive than CT for detection of malignant melanoma metastases and increases the accuracy of staging. The value of FDG-PET in staging patients with melanoma was recognized early, making this among the first widely accepted indications for clinical PET imaging.

ACR Codes and Keywords:

References and General Discussion of PET Tumor Imaging Studies (Anatomic field:Vascular and Lymphatic Systems, Category:Misc)

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Case number: pt028

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