Therapeutic impact of 18F-FDG PET/CT for initial staging in patients with clinical stage I and IIA, HER2-positive, or triple-negative breast cancer.

PURPOSE: While 18F-FDG PET/CT (FDG-PET/CT) is consensual for clinical stage ≥ IIB breast cancers (BC), its benefit for stage I or IIA HER2+ or triple-negative breast cancer (TNBC) patients lacks sufficient evidence. We reported a single-institution, retrospective study evaluating FDG-PET/CT impact on patient management and staging for stage I or IIA HER2+ or Triple-Negative BC. METHODS: Patients who underwent FDG-PET/CT staging before any treatment between January 2015 and December 2020 at Oscar Lambret Center were included. EXCLUSIONS: patients with symptoms or conventional imaging suggestive of metastatic dissemination, or with prior malignancies. Initial stage was determined from mammography, breast ultrasound, breast MRI, and clinical examination. Staging and therapeutic impact based on FDG-PET/CT findings collected, including intra- (modification of dose/site/strategy in a type of management previously indicated) and inter-modality (modification of planned treatment strategy) changes. RESULTS: The cohort included 287 female patients with clinical stage I or IIA, HER2+ , or TNBC. Therapeutic impact observed for 18% of patients (n = 52), with 2% (n = 7) undergoing inter-modality change with omission of planned surgery. The impact on patient management was higher for stage IIA patients (20%, 47/237) than for stage I patients (10%, 5/50). Among stage IIA disease, changes in management were more important for T2N0 patients (22%, 44/205) than for T1N1 patients (9%, 3/32). While not statistically significant, trends suggest usefulness of FDG-PET/CT for T2N0 patients. CONCLUSION: Considering substantial therapeutic implications, our study suggests the usefulness of FDG-PET/CT for patients with stage IIA, HER2-positive, or Triple-Negative BC with tumor size > 2 cm (T2N0).

Typical Bone Scintigraphy Presentation of Erdheim-Chester Disease in a Patient Diagnosed With IgG4-Related Disease.

ABSTRACT: A 50-year-old woman presented a dry syndrome, joint pain, inflammatory syndrome, polyclonal hypergammaglobulinemia, and tubulointerstitial nephritis. Imaging studies (including FDG PET/CT) revealed infrarenal retroperitoneal fibrosis with periaortitis and hypermetabolic osteosclerotic lesions. Bone scintigraphy demonstrated intense uptake in the femoral, tibial, and radial regions, suggestive of non-Langerhans histiocytosis, specifically Erdheim-Chester disease. A bone biopsy confirmed the presence of IgG4-positive plasma cells but no histiocytes. The patient received corticosteroid therapy followed by rituximab, resulting in a complete response. This case suggests an atypical manifestation of bone lesions in IgG4-related disease, emphasizing the diagnostic challenge between IgG4-related disease and Erdheim-Chester disease.