The aim of this study was to evaluate the incremental value of cocktail 18F-FDG/18F-NaF PET/CT over 18F-FDG PET/CT alone for detection of skeletal metastases in breast cancer patients. Seventy patients with locally advanced/recurrent breast cancer were prospectively included. All patients underwent whole-body 18F-FDG PET/CT and cocktail 18F-FDG/18F-NaF PET/CT within a span of 1 week. Both studies were evaluated to detect presence of skeletal/marrow metastases on PET/CT images by 2 nuclear medicine physicians. Clinical and radiological correlation/follow-up was used as criterion standard. Of 70 patients, 50 (71.0%) had locally advanced breast cancer, and 20 had recurrent breast cancer. On patient-wise analysis, both cocktail PET/CT and 18F-FDG PET/CT identified skeletal/marrow lesions in 23 (32.8%) of 70 patients. In 8 patients (11.4%), only cocktail PET/CT identified skeletal/marrow lesions, whereas 18F-FDG PET/CT was negative. In the rest of the 39 patients (55.8%), no skeletal/marrow lesion was identified on both scans. Good correlation was noted between cocktail PET/CT and 18F-FDG PET/CT results (r = 0.785, P < 0.0001). Cocktail PET/CT detected lesions in significantly more number of patients than 18F-FDG PET/CT alone (P = 0.007). On lesion-wise analysis, cocktail PET/CT detected more number of lesions in 20 patients as compared with 18F-FDG-PET/CT alone. Both scans detected same number of lesions in the rest of 11 patients with positive findings. A total of 32 additional lesions were identified on cocktail PET/CT imaging as compared with 18F PET/CT alone (P < 0.0001). Cocktail 18F-FDG and 18F-NaF PET/CT is superior to 18F-FDG PET/CT alone for the detection of skeletal/marrow metastases in breast cancer. It can be a better alternative to 18F-FDG PET/CT alone in facilities where both tracers are available.

Background: Growing teratoma syndrome is a rare phenomenon seen in nonseminomatous germ cell tumors after chemotherapy, where the tumor grows paradoxically despite normalization of tumor markers. It has been found in various locations, most commonly, the retroperitoneum in association with metastatic disease. The occurrence of growing teratoma syndrome in a mediastinal primary is very rare and there are only a few reports in the literature. Methods: In a retrospective review, out of 12 patients with mediastinal involvement by a germ cell tumor, 5 had a primary from the mediastinum. We present a series of 3 cases of primary germ cell tumor of the mediastinum, which after chemotherapy, fulfilled the criteria for growing teratoma syndrome and were managed with surgical excision. Conclusion: Development of growing teratoma syndrome in a primary mediastinal germ cell tumor is extremely rare. Its awareness and early detection can lead to successful surgical excision and long-term cure.

Aims: Invasive duct carcinoma, no special type (IDC, NST), of the breast with signet-ring cell differentiation is uncommon. This study was undertaken to describe the clinicopathologic characteristics of IDC, NST, with dominant signet-ring cell differentiation, and look for microsatellite instability in these tumors. Methods: Cases of IDC, NST, with dominant signet-ring cell differentiation, diagnosed over the past 2 years, were retrieved. Detailed clinical and pathologic analyses were performed. Immunohistochemistry was performed for estrogen receptor, progesterone receptors, Her-2 neu, Ki-67, E-cadherin, CK7, and CK20. Microsatellite instability was examined using immunohistochemistry for the 4 mismatch repair proteins: MLH1, MSH2, MSH6, and PMS2. Results: Of the total 1646 cases of IDC, NST, only 5 cases showed dominant signet-ring cells (ranging from 70% to 100%) and strong E-cadherin positivity and were diagnosed as IDC, NST, with dominant signet-ring cell differentiation. The age ranged from 32 to 65 years. Two cases were of histologic grade 3 and the remaining cases were grade 2 tumors. Four patients had T2 tumor and 1 had T3 tumor. All cases had axillary lymph node metastasis and distant metastasis was present in 1 case. All cases were microsatellite stable. Conclusions: Signet-ring cell differentiation in IDC, NST, is rare and associated with a high histologic grade. Lymph node metastasis and distant metastasis are common, indicating an aggressive clinical behavior. Thus, they should be recognized separately as they may warrant aggressive management. However, these are microsatellite-stable tumors in contrast to signet-ring cell tumors of other organs.