Inverted FDG Uptake Pattern in Subcutaneous Panniculitis-Like T-Cell Lymphoma

Area of Science:

• Oncology
• Nuclear Medicine
• Dermatopathology

Background:

• Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a rare T-cell lymphoma.
• SPTCL typically involves subcutaneous adipose tissue with minimal or absent lymph node involvement.
• Diagnosis can be challenging due to its varied presentation.

Observation:

• A 47-year-old woman presented with subcutaneous nodules, erythema, and fever.
• 18F-FDG PET imaging revealed an inverted uptake pattern, with higher activity in subcutaneous lesions compared to lymph nodes.
• Histopathological examination of an inguinal lesion showed extensive lymphocyte infiltration in adipose tissue with characteristic rimming adipocytes.

Findings:

• The patient was diagnosed with subcutaneous panniculitis-like T-cell lymphoma (SPTCL).
• The findings underscore the typical pattern of SPTCL with predominant subcutaneous infiltration and minimal lymph node involvement.
• The inverted FDG uptake pattern on PET imaging was a key diagnostic clue.

Implications:

• This case emphasizes the diagnostic utility of 18F-FDG PET in identifying SPTCL based on inverted uptake patterns.
• Recognizing this specific PET finding can aid in earlier and more accurate diagnosis of SPTCL.
• The study highlights the importance of correlating imaging findings with histopathology for definitive diagnosis.