case_images: PMC10578410_01
case_images: ACTH trends over time.
case_images: luac035f1.jpg
case_images: PMC10578410_01_luac035f1.jpg
case_images: luac035-F1
case_images: Between 2007 and 2019, the patient's ACTH levels rose (Fig. 1).
case_images: Select axial PET (A, D) CT (C, F) and PET/CT fusion (B, E) slices of a pancreatic tail lesion (arrow) with intense focal FDG uptake on [18F]FDG-PET/CT (A, B, C) and uncharacteristic absence of increased uptake on [68Ga]DOTATOC PET/CT (D, E, F) corresponding to a well-differentiated grade 1 pancreatic neuroendocrine tumor secreting ACTH.
case_images: luac035f2.jpg
case_images: PMC10578410_01_luac035f2.jpg
case_images: luac035-F2
case_images: As somatostatin analog activity reflects differentiated tissue and FDG activity characterizes more aggressive lesions, findings were concerning for a high-grade neuroendocrine tumor (NET) or an incidental pancreatic carcinoma (Fig. 2).
case_images: Select axial slices on triphasic CT abdomen of a subtle pancreatic tail lesion (arrow), with nearly the same attenuation as the neighboring pancreatic parenchyma on non-contrast (A), arterial phase (B), and venous phase (C) images. In retrospect, the same small lesion could be seen on a CT abdomen performed a decade prior (D), understandably misinterpreted as a pancreatic tail lobulation.
case_images: luac035f3.jpg
case_images: PMC10578410_01_luac035f3.jpg
case_images: luac035-F3
case_images: At that point, a tri-phasic CT of the pancreas was performed, confirming a small subtle lobulation of tissue confluent with the posterior pancreatic tail, isoattenuating to the pancreas in all 3 phases (Fig. 3).
case_images: Well-differentiated pancreatic neuroendocrine tumor. (A) Hematoxylin and eosin staining, 10x magnification. (B) Immunohistochemical findings for Ki-67, 10x magnification. (C) Chromogranin positive. (D) Synaptophysin positive. (E) ACTH positive. (F) Somatostatin <1% of cells positive.
case_images: luac035f4.jpg
case_images: PMC10578410_01_luac035f4.jpg
case_images: luac035-F4
case_images: Histopathology confirmed a 1.7-cm well-differentiated grade 1 pancreatic NET, (Ki67 index 1.5%) and moderately strong reactivity to ACTH on immunohistochemistry (Fig. 4).