case_images: PMC8116796_01
case_images: The timeline of patient's treatment history and the response of the tumor lesions. (A) Time line; (B) The radiographic imaging of pancreatic and metastatic liver lesions.
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case_images: The patient's clinical course was illustrated in  Figure 1A . An abdomen computed tomography (CT) indicated a tumor measuring 7 x 6 cm located in the tail of the pancreas that invaded the posterior wall of the stomach and the splenic artery, accompanied by multiple hepatic and lymph node metastases in the left supraclavicular fossa ( Figure 1B ). A sequencing performed on the biopsied specimen revealed a stop-gain mutation in BRCA2 exon 11 (c.1830A>T, p.K944*) ( Figure S1 ), which has been reported as a pathogenic germline mutation. The combined chemotherapy was initiated in July, 2018 ( Figure 1A ). After five cycles of treatment, the patient achieved partial response (PR) on primary pancreatic and metastatic lesions revealed by a total abdomen CT scan ( Figure 1B ) and the serum biomarkers (CA19.9, A magnetic resonance imaging (MRI) was performed in March, 2019 after 10 cycles of combined chemotherapy and showed that both hepatic and lymph node metastases (regional and distanced lymph nodes) achieved complete response (CR) and the primary pancreatic lesion shrank from the initial 5.7 to 1.5 cm in diameter ( Figure 1B ).
case_images: Hematoxylin and eosin (HE) stain of the pancreaticlesion. (A) The biopsy of the pancreatic lesion for initial diagnosis indicated squamous cell carcinoma (200x). (B) The HE stain of the surgical sample after the combined chemotherapy (100x).
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case_images: Subsequently an endoscopic ultrasound (EUS)-guided biopsy was performed on the pancreatic lesion and the histological and immunohistochemically tests confirmed a cT4N1M1 primary pure squamous cell carcinoma ( Figure 2A ). Histological examination of the resected specimens revealed severe tumor degeneration after the combined chemotherapy ( Figure 2B ) with vital tumor cells present only in small areas of primary and liver metastatic lesions.