case_images: PMC10686627_01
case_images: Histology, immunohistochemistry, and silver-enhanced in situ hybridization (SISH) of the patient's tumor sample. a Tumor cells have a very typical large eosinophilic cytoplasm. The active mitosis (encircled) is further visible. b Immunohistochemistry for HER2 (clone 4B5, Ventana, Roche Diagnostics International, Rotkreuz, Switzerland): strong circular expression in most tumor cells (score 3+; brown) in comparison to negativity in the healthy parotid tissue (circle). c HER2-SISH (Ventana, HER2 Dual ISH DNA Probe, Roche Diagnostics International, Rotkreuz, Switzerland) with amplified HER2 gene status in tumor tissue (black signals, red circle) compared to healthy nuclei.
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case_images: F1
case_images: With the intention to further detect potential characteristics for personalized therapies in the patient's tumor, an extensive pathological workup and immunohistochemistry of the tumor tissue was performed and revealed that the tumor was HER-2-positive for both the cell membrane and cytoplasm of tumor cells (IHC score 3; silver-enhanced in situ hybridization) yet PD-L1-negative as shown in Figure 1a-c.
case_images: a CT scan of the pelvic region showing a clearly in size progressive intraosseous metastasis in the right posterior superior iliac spine before T-DM1 treatment. b CT scan of the lung showing several metastases in the right and left lung. c CT scan of the pelvic region 2 months after the initiation of T-DM1 treatment. d CT scan of the lung 2 months after the initiation of T-DM1 treatment, demonstrating a robust partial remission. There is a moderate pleural infusion and atelectasis visible in the right lung.
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case_images: F2
case_images: In October 2020, he underwent one more FDG-PET scan showing again a good partial metabolic response, which indicated that T-DM1 led to a robust partial remission as shown in Figure 2a-d (40% reduction of SUV max).
case_images: Graphic of ePROs reported from the patient during his treatment with T-DM1. Drug-induced timing and correlation to tumor size according to SUVmax (PET scan) are indicated in violet and yellow. Light blue, well-being; blue circle, sleep problems; red, edema of limbs; mint green, limb/muscle pain; blue x, headache; orange, itching or wheals; brown, constipation. ePROs, electronically captured patient-reported outcomes.
case_images: cro-2023-0016-0001-535097_F03.jpg
case_images: PMC10686627_01_cro-2023-0016-0001-535097_F03.jpg
case_images: F3
case_images: Of note, during this treatment phase, the patient used the smartphone app medidux  for standardized and structured reporting of treatment-related toxicities and well-being, which also indicated that his quality of life was conserved and no dose limiting toxicities occurred (see example under TDM-1 therapy; shown in Fig. 3).