INVESTIGATIONS AND DIAGNOSIS
Upon experiencing dizziness and palpitations following admission,
intravenous blood glucose measured 32.58 mg/dL, insulin level was 108.7
mIU/L, and the insulin release index (IRI/G) was calculated as 3.32. The
results of the glucose tolerance test, C-peptide measurement, and
insulin release test are presented in Table 1. Abnormal findings
included blood tests, liver and kidney function, glycosylated hemoglobin
levels, tumor markers, adrenocorticotropic hormone, cortisol, thyroid
function, parathyroid hormone, growth hormone, and sex hormones. Thyroid
function, parathyroid hormone, growth hormone, and sex hormone levels
were within normal limits. Abdominal imaging revealed no abnormalities.
Ultrasound endoscopy revealed a hypoechoic nodule in the pancreatic
neck, measuring approximately 11.2 × 12.7 mm (Figure 1). Ultrasound
endoscopy-guided puncture of the pancreatic nodule revealed pancreatic
tissue strip lesions, characterized by epithelioid cells arranged in a
nest-like pattern. Uniform cell size and cytoplasmic richness were
noted. A neuroendocrine tumor was suspected (Figure 2 and Figure 3).
Following transfer to general surgery department, post-abdominal
exploration revealed an approximately 1 cm diameter nodule in the
pancreatic neck (Figure 4). Intraoperative ultrasound confirmed a
hyperechoic nodule in the same location. Pancreaticoduodenectomy was
subsequently performed. The postoperative autopsy specimen revealed a
well-defined mass, measuring 1.2 × 1.4 cm, located in the pancreatic
neck (see Figure 5). The intraoperative rapid pathology report confirmed
the presence of a neuroendocrine tumor. Postoperative histopathology
demonstrated anisotropic cell proliferation within the pancreatic
tissue, characterized by glandular duct-like and small nest-like
structures(see Figure 6). The tumor cells exhibited uniformity and
minimal heterogeneity, consistent with a neuroendocrine tumor.