From Widespread Cutaneous to Systemic Nodal Involvement: Serial FDG PET/CT Findings in Follicular Lymphoma

Area of Science:

• Nuclear Medicine
• Oncology
• Radiology

Background:

• Follicular lymphoma (FL) is a common indolent non-Hodgkin lymphoma.
• Cutaneous involvement can occur in FL, sometimes presenting as diffuse disease.
• 18F-FDG PET/CT is a standard imaging modality for staging and response assessment in lymphoma.

Purpose of the Study:

• To highlight the utility of serial whole-body 18F-FDG PET/CT in identifying atypical disease progression in follicular lymphoma.
• To illustrate a case of follicular lymphoma with unusual post-therapy response patterns.

Main Methods:

• A 57-year-old woman with biopsy-proven follicular lymphoma underwent baseline 18F-FDG PET/CT.
• The patient received therapy for diffuse cutaneous and subcutaneous involvement.
• Follow-up 18F-FDG PET/CT was performed to assess treatment response and disease status.

Main Results:

• Baseline 18F-FDG PET/CT showed extensive cutaneous and subcutaneous disease.
• Post-therapy imaging revealed resolution of cutaneous uptake.
• However, follow-up PET/CT demonstrated new, widespread, confluent hypermetabolic lymphadenopathy, indicating systemic progression.

Conclusions:

• This case underscores the importance of serial whole-body PET/CT imaging in evaluating follicular lymphoma, especially in atypical presentations.
• Apparent treatment response in one compartment (skin) may mask systemic progression elsewhere (lymph nodes).
• Serial imaging is essential for accurate staging and management of follicular lymphoma post-therapy.