Focal F-18 Fluorodexyglucose Positron Emission Tomography Uptake In A Hyalinized Nodule As A False Positive Splenic Metastasis In A Patient With Breast Cancer And Metastatic Thyroid Cancer

A 79-year-old female with a history of breast cancer and Hurthle cell carcinoma of the thyroid was found to have a splenic mass on CT, with increased Tc-99m HDP uptake on a bone scan, enhanced on MRI, and was intensely hypermetabolic on F-18 FDG PET. Metastatic thyroid cancer was found in the left iliac bone. No splenic uptake was present on iodine-131 whole body scanning. Biopsy of the splenic mass revealed a hyalinized nodule, resulting from a nongranulomatous response to damage leading to organization of collagenous matrix, fibroblasts, and lymphocytes without evidence of malignancy.