case_images: PMC10073532_01
case_images: CT results. (A) CT result on April 25, 2022; (B) CT result on May 17, 2022.
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case_images: Contrast-enhanced CT showed an irregularly thickened left ureter with a soft tissue mass observed throughout the ureter (5.5cmx5.2cm,  Figure 1A ). On 17 May 2022, a plain CT scan of the whole abdomen was performed, which detected pneumoperitoneum along with irregular thickening of the wall throughout the left ureter and formation of a soft tissue mass (5.9 cmx5.3 cm), showing multiple surrounding lymph nodes ( Figure 1B ).
case_images: Electrocardiogram results. (A) electrocardiogram results on May 16, 2022; (B) electrocardiogram results on June 6, 2022; (C) electrocardiogram results on June 14, 2022.
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case_images: Routine ECG showed visible first-degree atrioventricular block and Q waves ( Figure 2A ). The bedside ECG at 11:45 am showed changes in ST-T, with the possibility of acute inferior wall cardiac infarction and first-degree atrioventricular blockage combined with clinical symptoms ( Figure 2B ). Abnormal Q waves were seen in V1 V2 leads with the first-degree atrioventricular block ( Figure 2C ).
case_images: Immunohistochemical results (400x). (A) Hematoxylin and eosin-stained section result; (B) CD56 staining specific for neuroendocrine differentiation; (C) CK-L staining specific for neuroendocrine differentiation; (D) CK-pan staining specific for neuroendocrine differentiation; (E) GATA-3 staining specific for neuroendocrine differentiation; (F) Ki-67 staining specific for neuroendocrine differentiation; (G) Syn staining specific for neuroendocrine differentiation.
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case_images: The immunohistochemical test revealed positive neuroendocrine markers (CD56, CK-L, CK-pan, GATA-3, Ki-67 and Syn), consistent with small cell neuroendocrine carcinoma ( Figure 3 ).
case_images: Cardiac enzyme profile examination results. (A) AST results; (B) BNP results; (C) CK results; (D) CK-MB results; (E) hsTnl results; (F) LDH results.
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case_images: The patient's condition improved, and the cardiac enzyme profile and troponin showed a progressive decline to normal levels ( Figure 4 ), and was discharged.
case_images: The timeline with relevant data from the episode of care.
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case_images: A timeline with relevant data from the episode of care was showed in  Figure 5 .