Positively labeled white blood cell scan with eosinophilia and absence of infection

The authors describe the variability of Tc-99m exametazime-labeled leukocyte distribution as a function of the relative frequency of white cell types in the labeled blood.

A 76-year-old man who was hospitalized with fever and possible postoperative osteomyelitis underwent scintigraphic imaging with Tc-99m exametazime-labeled leukocytes.

The white cell scan excluded any discrete focus of infection and revealed diffuse involvement of the lymph nodes and skin. The pathologic diagnosis was angioimmunoblastic T-cell lymphoma. The atypical infiltrates seen on the white cell scan can be explained by the severe eosinophilic blood count on the day of leukocyte labeling (total leukocyte count: 8,100 cells/microl with 63% neutrophils, 8.9% lymphocytes, and 22.2% eosinophils).

In the labeling of the leukocyte moiety, a higher presence of any leukocyte subpopulation will modify the biodistribution and thus the image interpretation.