Desmoplastic melanoma: True positive and false negative findings on F-18 FDG-PET/CT

Desmoplastic melanoma is a rare subtype of malignant melanoma, which is unusual in that it is more often associated with local recurrence than with lymph node or distant metastatic spread. The histologic architecture of this melanoma subtype differs from conventional melanoma in that the melanoma cells are interspersed within an abundant collagenous stroma. We present a case that demonstrates both true positive and false negative findings on F-18 FDG PET/CT imaging in a case of recurrent desmoplastic melanoma.