Melanoma Case 02


Clinical History
50-year-old woman with a history of recurrent melanoma, status post wide excision of known metastasis to the left breast, was referred for a restaging PET/CT scan.

Imaging Findings
NUCLEAR MEDICINE PET/CT
STATED REASON FOR REQUEST: Restaging melanoma
TECHNIQUE: Emission scanning was performed extending from the neck through the pelvis approximately 1 hour post radiotracer injection. Images were reconstructed with and without attenuation correction using the CT attenuation coefficients.
BLOOD GLUCOSE: 78 mg/dL


PET/CT FINDINGS: There was a single focal area of moderately increased radiopharmaceutical uptake in the left axilla resting against the chest wall, which was suspicious for metastatic disease. This area corresponded to a very small nodal structure on the CT portion of the exam. The large left breast mass seen on the CT portion of the exam did not demonstrate increased uptake of radiopharmaceutical, and the doctor determined it may represent a postoperative seroma.

Discussion
This patient was sent for restaging PET/CT after having an excisional biopsy with positive margins in the left breast. On the CT portion of the exam she had a large left breast mass which was equivocal by anatomical imaging alone, but thought to be postoperative in nature given the rapid rate that it had developed.

This case shows how even small melanoma metastases are often times picked up and exquisitely localized using combined PET/CT. This small chest wall node was not seen prospectively on the CT portion of this exam. Subsequent excision found it to be a small melanoma metastasis.

In addition, the PET/CT exam was helpful in excluding the larger breast mass, which had very little radiopharmaceutical uptake and was compatible with a postoperative seroma, and became much smaller on subsequent exams.

In general melanoma is one of the most glucose avid tumors, which enables not only detection of small lesions, but also exclusion of large lesions that do not demonstrate significant radiopharmaceutical uptake.

Data courtesy of Dr. Todd Blodgett, University of Pittsburgh Medical Center, Pittsburgh, PA, USA

* Any of the protocols presented herein are for informational purposes and are not meant to substitute for clinician judgment in how best to use any medical devices. It is the clinician that makes all diagnostic determinations based upon education, learning and experience.