Thallium-201 uptake in eosinophilic granuloma of the frontal bone: comparison with technetium-99m-MDP imaging

An 11-yr-old female presented with a 6-wk history of left upper lid tenderness and left eye lacrimation. Left lateral supraorbital mass and left preauricular lymph node were the only significant physical examination findings. On skull x-ray, a left frontal bone defect was noted. CT and MRI showed a soft-tissue mass in the area of the bone defect. Bone scintigraphy exhibited peripheral uptake within the central photon deficient area. With 201TI SPECT, high uptake was noted on early and delayed images. Diagnosis of eosinophilic granuloma was performed by biopsy. Since thallium uptake was seen in the area where photon deficiency was exhibited by 99mTc-MDP scintigraphy, we speculate that thallium SPECT could detect eosinophilic granuloma when radiographic skeletal survey or radionuclide bone scan are equivocal. It could also rule out multiple bone involvement and recurrence or regrowth after therapy.