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Background: This report examines (99m)Tc-etarfolatide imaging to identify the presence of folate receptor (FR) on tumors of women with recurrent/refractory ovarian or endometrial cancer and correlates expression with response to FR-targeted therapy (vintafolide)., Patients and Methods: In this phase II, single-arm, multicenter study, patients with advanced ovarian cancer were imaged with (99m)Tc-etarfolatide before vintafolide treatment. Up to 10 target lesions (TLs) were selected based on Response Evaluation Criteria In Solid Tumors criteria using computed tomography scans. Single-photon emission computed tomography images of TLs were assessed for (99m)Tc-etarfolatide uptake as either FR positive or negative. Patients were categorized by percentage of TLs positive and grouped as FR(100%), FR(10%-90%), and FR(0%). Lesion and patient response were correlated with etarfolatide uptake., Results: Forty-nine patients were enrolled; 43 were available for analysis. One hundred thirty-nine lesions were (99m)Tc-etarfolatide evaluable: 110 FR positive and 29 FR negative. Lesion disease control rate (DCR = stable or response) was observed in 56.4% of FR-positive lesions versus 20.7% of FR-negative lesions (P < 0.001). Patient DCR was 57%, 36%, and 33% in FR(100%), FR(10%-90%), and FR(0%) patients, respectively. Median overall survival was 14.6, 9.6, and 3.0 months in FR(100%), FR(10%-90%), and FR(0%) patients, respectively., Conclusions: Overall response to FR-targeted therapy and DCR correlate with FR positivity demonstrated by (99m)Tc-etarfolatide imaging., Clinical Trial Number: NCT00507741.

Retroperitoneal malignant peripheral nerve sheath tumor (MPNST), a rare type of neurogenic tumor, was diagnosed in a 14-year-old girl with a history of neurofibromatosis type 1 (NF1). Immunochemistry demonstrated spindle cells positive for S-100 protein. The patient had multiple tumor recurrences and she was evaluated with serial F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET). A tumor in the right iliac wing showed increased FDG uptake on PET. FDG-PET played an important role in therapy planning and subsequent follow up. This case emphasizes the important role FDG-PET could play in the staging, restaging, and posttherapy follow up of MPNST.

The authors describe various patterns of F-18 fluorodeoxyglucose (FDG) accumulation in the diaphragm and crura. They present 6 patients in whom incidental diaphragmatic and crural uptake of FDG was observed during positron emission tomography (PET). Hyperventilation is thought to be the potential underlying mechanism of this condition.