OBJECTIVE. The objective of this study was to investigate the clinical, morphologic, and pathologic features associated with increased 18F-FDG uptake in benign schwannomas. MATERIALS AND METHODS. Twenty-two schwannomas in 22 patients (age range, 25–81 years) who had FDG PET or PET/CT scans and subsequently underwent surgical re-section were retrospectively analyzed. The maximum standardized uptake value (SUVmax) was compared with patient age, sex, tumor location (gastrointestinal vs nongastrointestinal origin), tumor size, gross appearance, intratumoral cellularity, intratumoral infiltration of inflammatory cells, presence of peritumoral lymphoid cuffs, and expression status of glucose transporters 1 and 3 on tumor cells. RESULTS. The SUVmax of schwannomas ranged from 1.5 to 17.3 (median, 3.7). Significantly higher SUVmax was observed in gastrointestinal schwannomas (n = 4) compared with nongastrointestinal schwannomas (n = 18, p = 0.007) and in schwannomas with peritumoral lymphoid cuffs (n = 5) compared...

Retained textiles with foreign body granulomatous reaction can form mass-mimicking soft tissue tumors, which may cause diagnostic, clinical, and medicolegal problems. In this study, we present 3 cases of foreign body granuloma by retained textiles, and demonstrate FDG PET findings with detailed pathologic correlation. We also provide a review of previous literatures. Three patients (all females; age range, 48–61 years) with histopathologic diagnosis of mass-forming foreign body granuloma caused by retained textiles were retrospectively studied. They underwent an FDG PET scan in our institute. The mass was located in the abdominopelvic cavity in all cases. The time interval between the prior surgery and the PET acquisition was 11 months, 15 or 19 years, and 26 years, respectively. Intense FDG uptake with a ring-shaped pattern was observed in 2 cases, while no uptake in 1 case. Microscopically, 2 with ring-shaped FDG uptake showed a cellular foreign body reaction peripherally, and artificial textile fibers and acellular eosinophilic amorphous materials in the central portion. In the one without FDG uptake, the mass was composed of mainly necrotic debris surrounding by a thick layer of well-formed collagen fibers. In previous case reports describing the accumulation of FDG in foreign body granulomas, 9 of 10 cases showed intense FDG uptake with a ring-shaped pattern. The ring-shaped pattern of FDG uptake seems to well characterize pseudotumor with foreign body granulomas. However, the pattern of FDG accumulation in retained textile with foreign body granulomas may vary due to histologic features.

Dedicated breast positron emission tomography (dbPET) is a new diagnostic imaging modality recently used in clinical practice for the detection of breast cancer and the assessment of tumor biology. dbPET has higher spatial resolution than that of conventional whole body PET systems, allowing recognition of detailed morphological attributes of radiotracer accumulation within the breast. ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) accumulation in the breast may be due to benign or malignant entities, and recent studies suggest that morphology characterization of ¹⁸F-FDG uptake could aid in estimating the probability of malignancy. However, across the world, there are many descriptors of breast ¹⁸F-FDG uptake, limiting comparisons between studies. In this article, we propose a lexicon for breast radiotracer uptake to standardize description and reporting of image findings on dbPET, consisting of terms for image quality, radiotracer fibroglandular uptake, breast lesion uptake.