Anales de la RANM

93 A N A L E S R A N M R E V I S T A F U N D A D A E N 1 8 7 9 CONTRIBUTION OF 18F-FDG PET/CT IN OCCULT BREAST CARCINOMA Valhondo-Rama, et al. An RANM. 2021;138(01): 92 - 95 PATIENT 1: In January 2013 right axillary adenopathies were detected in a 63-year-old woman by MM, MRI, and US without lesions in mammary parenchyma. FNAC and biopsy confirmed metastases of infiltrating Luminal A lobular carcinoma. WB 18 F-FDG PET/CT showed multiple right axillary adenopathies plus a pathological FDG deposit in a subcarinal lymph node (Figure 1) , whose FNAC reported metastasis of breast adenocarcinoma, which directly supposes stage IV. Neoadjuvant hormone therapy was initiated (Letrozole). Neoadjuvant chemotherapy was rejected due to comorbidities. Right axillary lymphadenectomy showed 6 of 15 nodes with macrometastasis. She received 50 Grays (Gy) of adjuvant radiotherapy (RT) on right breast, axilla and supraclavicular region plus mediastinum, and continued with Letrozole. During follow-up, high CEA value was spotted four years later. Ca 15.3, whole-body bone scintigraphy, colonoscopy and oral panendoscopy were normal. PET/CT however reported left pleural implants (Figure 2.A) . Fulvestrant was initiated but CEA level persisted high. New PET/CT study showed enlargement of the pleural implants (Figure 2.B) . Chemotherapy was changed to Exemestane-Everolimus. After 16 months of stabilization, PET/CT revealed again progression of pleural implants (Figure 2.C) . Therapy with Nab-Paclitaxel was agreed but changed into Tamoxifen because of poor tolerance. Currently, she remains stable with Tamoxifen on follow-up with mammography, tumour markers and WB 18 F-FDG PET/CT (last follow-up on December 2020) with no lesions identified in breast tissue. Figure 1. Patient 1. First WB18F-FDG PET/C. Axial planes, (A) CT, (B) PET/CT, (C) PET. Green arrows: the largest axillary adenopathy (1.8 cm) with maximum standard uptake value on PET (SUVmax)= 5,6. Blue arrows: subcarinal adenopathy (1.4 cm, SUVmax 5.1). Figure 2. Patient 1. WB18F-FDG PET/CT, axial planes. (A) January 2017: left pleural implants (yellow arrows), with SUVmax 3.4. (B) September 2017: progression of pleural implants (blue arrows). (C) January 2019: progression of pleural implants (green arrows); inflammatory FDG uptake in left shoulder muscles (asterisk). CASES REPORT