Avid FDG Uptake Research Articles

Calyceal Rupture Secondary to Ureteric Obstruction by Recurrent Colorectal Carcinoma

Abstract: A 65-year-old man presented with a change in bowel habits 28 months after colonic resection for carcinoma. FDG PET/CT imaging was performed to assess for recurrent disease. This showed a 3-cm presacral soft tissue mass within which there was avid FDG uptake consistent with local recurrence. This mass had resulted in obstruction of the left distal ureter with resultant hydronephroureter; in addition, there was evidence of calyceal rupture with extravasation of FDG-containing urine into the perirenal space. The patient had no symptoms related to this renal abnormality and the calyceal rupture was therefore managed conservatively.

F-18 Fluorodeoxyglucose PET/CT as an Imaging Tool for Staging and Restaging Cutaneous Angiosarcoma of the Scalp

Cutaneous angiosarcoma of the scalp is a rare highly aggressive malignant tumor that typically afflicts elderly patients and commonly presents with extensive local spread and distant metastasis. Distant metastases favor lung, liver, lymph nodes, and skin. Overall, the prognosis is poor. It differs from other soft tissue sarcomas in that the size of the lesion at presentation instead of tumor grade is the important prognostic factor. Optimal treatment is yet to be determined. Wide-margin complete excision with postoperative radiotherapy has been the most effective therapy. Chemotherapy and gene therapy have been used with some success. Local extent is critical in surgical planning, especially in the head and face, and is difficult to determine accurately with clinical examination and morphologic imaging tools. We report the case of a 70-year-old man diagnosed with multifocal angiosarcoma of the scalp. PET/CT imaging with F-18 2-fluoro-2-deoxyglucose (F-18 FDG) not only showed avid FDG uptake by an angiosarcoma (SUVmax = 10.7), but also simultaneously showed local extension of multifocal lesions with periosteal involvement and excluded metastatic abdominal nodal disease. PET/CT imaging after chemotherapy and before radiation therapy showed complete resolution of FDG uptake in the scalp and osseous lesions. Evaluation of more cases of this subset of soft tissue sarcoma with FDG PET/CT may suggest a possible role in not only staging angiosarcomas to determine the extent of local as well as distant disease, but also to potentially help determine response to therapy and early recognition of local or distant recurrence.