FDG PET/CT in Anaplastic Lymphoma Kinase-Positive Anaplastic Large Cell Lymphoma

Area of Science:

• Oncology
• Nuclear Medicine
• Pediatric Hematology-Oncology

Background:

• Anaplastic large cell lymphoma (ALCL) is a rare non-Hodgkin's lymphoma.
• Anaplastic lymphoma kinase (ALK) gene rearrangements are found in 60%-85% of systemic ALCL cases.
• ALCL is known for its aggressive nature and potential for rapid progression.

Observation:

• A case study of an 11-year-old boy diagnosed with ALCL.
• Serial FDG PET/CT scans were utilized to monitor treatment response.
• Interim scans showed partial response, and end-of-treatment scans indicated complete metabolic response.

Findings:

• Despite achieving a complete metabolic response, the patient relapsed within two weeks.
• Cytological confirmation supported the early relapse.
• This highlights a potential discordance between metabolic imaging and clinical relapse in ALCL.

Implications:

• The aggressive nature of ALCL necessitates heightened awareness of potential early relapses.
• FDG PET/CT, while valuable, may not always predict or prevent very early post-treatment recurrence.
• Close monitoring and prompt diagnostic confirmation are crucial for managing ALCL patients, especially children.