Diplopia Related to a Pediatric Cervical Rhabdoid Tumor in 18 F-FDG PET

Area of Science:

• Nuclear Medicine
• Oncology
• Ophthalmology

Background:

• 18F-FDG PET/CT commonly shows increased muscle uptake due to physiological glucose metabolism.
• Muscle uptake on 18F-FDG PET/CT often indicates recent muscle activity.
• The significance of absent muscle uptake on 18F-FDG PET/CT is rarely discussed.

Observation:

• A case study of an 8-year-old boy with an extrarenal rhabdoid tumor in the right carotid space.
• Diagnostic workup included MRI and 18F-FDG PET/CT.
• Notably, no 18F-FDG uptake was observed in the lateral rectus oculomotor muscle, contrasting with other oculomotor muscles.

Findings:

• The absence of 18F-FDG uptake in the lateral rectus muscle was a unique finding.
• Ophthalmological examination revealed diplopia.
• The diplopia was confirmed using the Lancaster test.

Implications:

• This case highlights the potential diagnostic value of absent muscle uptake on 18F-FDG PET/CT.
• It suggests that focal muscle de-innervation or dysfunction may manifest as a lack of radiotracer uptake.
• Further research is warranted to explore the interpretation and clinical utility of absent muscle FDG uptake in various conditions.