ABSTRACT
OBJECTIVE: We aimed to evaluate the diagnostic impact of 18F-FDG PET/CT in staging apocrine breast carcinoma (ABC) and primary breast neuroendocrine carcinoma (PBNEC) and to demonstrate possible alterations of the 18F-FDG uptake in these histopathologic subtypes. In addition, we aimed to compare 18F-FDG PET/CT findings between ABC, PBNEC and invasive ductal carcinoma. MATERIAL AND METHODS: A total of 570 patients and 585 breast lesions were retrospectively included in this study. After patients were classified into molecular subtypes according to the histopathological analysis, 18F-FDG PET/CT imaging was performed. The SUVmax findings of primary tumors obtained from 18F-FDG PET/CT were compared between the groups. RESULTS: Invasive ductal carcinoma was the most prevalent breast carcinoma (77.7%, n=446), with a low proportion of ABC (4.1%, n=24) and PBNEC (2.4%; n=14) diagnosed. The highest mean SUVmax was calculated in HER2 subtype of ABC and 18F-FDG uptake ratio in HER2 and TN subtypes were found statistically higher than Luminal B type of ABC (p=0.038 and p=0.019, respectively). Although 18F-FDG uptake in Luminal B subtype of PBNEC was higher than Luminal A subtype, difference was not statistically significant. Additionally, the axillary metastasis rate was significantly higher in the ABC group (p=0.015). CONCLUSIONS: The histopathological ABC subtype group showed different 18F-FDG uptake than the invasive ductal carcinoma group. Even if 18F-FDG uptake was lower in the PBNEC group than in the other groups, PET/CT showed and adequate performance in detecting primary tumors and metastases. The 18F-FDG PET/CT scan results may contribute to the initial staging and management of ABC and PBNEC patients.
