FDG-PET findings in pathologically identified lymph node, adenoid or splenic hyperplasia

Objectives False-positive results have been noted in the context of non-malignant inflammatory conditions. This study seeks to characterize FDG-PET (PET) findings in the specific context of biopsy proven non-malignant lymphoid hyperplasia.

Methods A patient search was performed using the PowerPath database of hematopathology specimens to identify lymph node, adenoid, and spleen cases with a diagnosis of hyperplasia. The database was searched from September 1, 2005 to May 5, 2008. Any cases which were diagnosed as malignant or lymphoma were excluded. Following patient identification, medical records were screened to determine if a PET scan had been performed. All PET scans were reviewed by at least one board certified nuclear medicine physician. SUV calculation were performed on the area later biopsied and maximum value using SUV max recorded.

Results Two hundred one (201) cases satisfied our criteria as being positive for hyperplasia and negative for malignancy or lymphoma. These cases consisted primarily of lymph node cases (173); the balance consisted of adenoid (25) and spleen (3) specimens.Of the 201 patients identified with lymphatic hyperplasia, fifty-two (52) had received a PET scan. Of the 52 patients who received a PET scan, forty-one (79%) were interpreted as PET positive. Mean SUV=4.4 ± 2.8 Range = 1.1 – 14.7.

Conclusions FDG-PET detects non-malignant lymphoid hyperplasia. This may result in a false- positive study in the context of cancer screening. Quantification of SUV levels is not helpful in differentiating benign from malignant cases.