PMC8531720_01
Examinations and histopathological results during work-up of the patient. (A) Upper gastrointestinal X-ray showed a stricture in the second portion of the duodenum. (B) Upper gastrointestinal endoscopy detected a stricture with circumferential edematous friable mucosa, extending from the duodenal bulb to the second portion of the duodenum. (C) PET/CT revealed duodenal wall was thickened and identified as metabolically active lesions (SUVmax=10.6) (D). (E) Thickened peritoneum and mesenteries and slightly larger lymph nodes in the mesenteries were found with intense FDG uptake (SUVmax=14.3) (F). (G) Holistic view of PET/CT: metabolic lesions in the duodenum, peritoneum and mesenteries. Exploratory laparotomy showed three metastatic nodules in the peritoneal cavity, including one nodule on the ligamentum teres hepatis (H) and the other two on the omentum (I) (arrows). Histopathological examination of primary breast cancer (J), metastatic axillary lymph node (K) and metastatic peritoneal nodule (L) all revealed single-file strands of infiltrating small tumor cells dispersed in the fibrous matrix (circle).
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An upper gastrointestinal X-ray ( Figure 1A ) and upper gastrointestinal endoscopy ( Figure 1B ) showed a stricture in the horizontal part of duodenum which had poor distension. Tomography/Computed Tomography (PET/CT) showed thickening of duodenal wall, peritoneum and mesenteries, slightly larger lymph nodes in the mesenteric area, and varying degrees of increase in glucose metabolism ( Figures 1C-G ); combined with perirenal, duodenal and bladder lesions, peritonitis was highly suspected, while tuberculous peritonitis was supposed to be excluded. Thereafter, a decision was made to perform an exploratory laparotomy. In the operation, approximately 1 liter of yellow-brown ascitic fluid was drained and three nodules were seen in the peritoneal cavity, including one nodule on the ligamentum teres hepatis ( Figure 1H ) and the other two on the omentum ( Figure 1I ). Similar to the primary breast cancer ( Figure 1J ) and metastatic axially lymph node ( Figure 1K ), histological examination of the peritoneal nodule showed single-file strands of infiltrating tumor cells throughout the fibrous matrix, which were consistent with ILC ( Figure 1L ).
Review of treatment process of the patient (from November 2012 to February 2020).
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Unfortunately, the patient died two months later due to disease progression with malignant ascites ( Figure 2 ).
Whole exome sequencing (WES) of tumor samples from primary lesion, regional lymph nodes and peritoneal metastatic lesions. (A) 3-way Venn Diagram showed the mutational overlaps in the three samples. There were 47 common mutations in the three samples, while another 21 common mutations between lymph node and metastatic site, and another 54 common mutations between lymph node and primary site. (B) Somatic mutation heatmap. The mark "*" means that there are 2 or more mutations in the same gene, which was labelled with gene or amino acid changes. Yellow means there is variation, while blue means there is no variation. (C) Variation frequency (VAF) distribution. The mark "*" means that there are 2 or more mutations in the same gene, which was labelled with gene or amino acid changes.
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The 3-way Venn Diagram showed that 47 common mutations were detected among primary lesion, lymph nodes and peritoneal metastatic lesions ( Figure 3A ); combined with somatic mutation heatmap ( Figure 3B ) and variation frequency (VAF) distribution ( Figure 3C ), it was implied that the three tumor samples may have the same origin.
Acquired mutations were detected in the sample of peritoneal metastatic lesion and visualized through Integrative Genomics Viewer (IGV). (A) Variant PIK3CA p.D959N IGV plot (all reads: 181, alternative allele supported reads: 26). (B) Variant ESR1 p.E380Q IGV plot (all reads: 399, alternative allele supported reads: 70).
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What' more, the sample of metastatic lesion was found to have acquired PIK3CA p.D959N ( Figure 4A ) and ESR1 p.E380Q mutation ( Figure 4B ), which were not detected in neither primary lesion nor lymph node.