Aggressive variant of primary cutaneous anaplastic large T-cell lymphoma: a new role for 18F-FDG PET/CT.

Primary cutaneous anaplastic large cell lymphoma (ALCL) represents less than 2% of all T-cell lymphomas and usually manifests as a solitary cutaneous lesion generally in older males. It is an indolent disorder with a survival rate of 90% at 10 years, and rarely shows extracutaneous dissemination. The FDG avidity of the lesions of cutaneous ALCL is the lowest reported among T-cell lymphoma subtypes. However, the available positron emission tomography (PET) literature has not taken account of a subtype of primary cutaneous ALCL that presents with extensive limb disease, has a much more aggressive course, and responds poorly to conventional therapy. We report serial F-18 FDG PET/CT imaging of a 72-year-old man with this aggressive subtype of primary cutaneous ALCL. This case demonstrates that despite the low reported sensitivity of FDG PET/CT in cutaneous ALCL, PET/CT may in fact play a vital role in identifying patients with the more aggressive extensive limb disease subtype, and help guide therapeutic decisions toward much better outcomes than currently achieved.