Metastatic breast cancer patient initially diagnosed with HER2 null (IHC 0) but rapidly progressing

A 67-year-old woman, navigated a complex journey with metastatic breast cancer, marked by evolving diagnostic results and treatment considerations.

In 2012, she was initially diagnosed with invasive lobular carcinoma (ILC) breast cancer, categorized as HER2-negative (IHC 0) following a biopsy of a neck lesion.

From 2017 to 2019, her condition showed signs of progression, prompting a comprehensive evaluation in 2019. An in vivo diagnostic comparison between FDG-PET and ABSCINT-HER2 PET/CT unveiled a complex landscape of moderate to high, heterogeneous tracer uptake in bone, adenopathy, and muscle invasion. Interestingly, ABSCINT-HER2 outshone FDG-PET in revealing additional bone metastases. A subsequent biopsy of a neck lesion yielded a HER2 low (IHC 2+) result.

In conclusion, Isabella’s journey witnessed a transition from an initial HER2-negative status to HER2-low (IHC 2+), hinting at either an evolutionary change in the cancer or a potential misdiagnosis at the outset. The sensitivity of ABSCINT-HER2 in detecting HER2 low lesions played a pivotal role in refining the diagnosis. Notably, the heterogeneity observed in the neck lesion emphasized the diverse nature of the tumor within the patient’s body, i.e. intra-tumor heterogeneity, shedding light on the intricate challenges in managing metastatic breast cancer.