PMC9702327_01
(A) Pretreatment magnetic resonance imaging (MRI) image depicting a multilobulated tumor with the size of 16.1 cm x 14.9 cm x 14.5 cm in the left upper abdomen. (B) Tumor progression up to the greatest diameter of 18 cm in the axial view of computerized tomography (CT) scans after treatment of Lanreotide. (C) Prominent tumor shrinkage after concurrent chemoradiation. (D) At least 50% reduction of tumor axial perpendicular diameters in preoperative CT.
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Further abdominal magnetic resonance imaging (MRI) showed a large multilobulated tumor with the size of 16.1 x 14.9 x 14.5 cm in the left upper abdomen ( Figure 1A ). CT scan 5 months later ( Figure 1B ). Coinciding with this, he complained about bulging abdomen interfering with digestion. On the third month of CCRT, MRI showed a continuously decreased tumor dimension ( Figure 1C ). The axial perpendicular diameters of the tumor reduced at least 50% in preoperative CT after CCRT ( Figure 1D ).
(A) Chromogranin, (B) synaptophysin, (C) somatostatin receptor 2A, and (D) monomorphous round to cuboidal cells arranging in solid and trabecular patterns. These cells have rich cytoplasm, and salt and pepper nuclei (hematoxylin-eosin stain; original magnification, 100x). (E) The immunohistochemical study reveals immunoreactivity of synaptophysin (original magnification, 100x).
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Immunohistochemical staining showed positive for chromogranin A, synaptophysin, and somatostatin receptor 2A (SSTR2A) ( Figures 2A-C ). Pathology confirmed a pancreatic NET with the size of 12 x 10 x 6 cm and weighed 315.9 g with American Joint Committee on Cancer (AJCC) stage II, ypT3 ( Figure 2 ).
(A) Isodose curves depicting a target volume of 1,910 cc in the initial treatment plan of Tomotherapy. (B) Target volume reduced from 1,910 to 1,057 cc after 14 fractions. (C) Target volume reduced from 1,057 to 605 cc after 10 fractions. (D) Multidisciplinary treatment course of the patient from the day of initial presentation until definitive surgery: adaptive Tomotherapy plans were administrated twice at the timing of substantial target volume reduction from 1910 to 1,057 cc and from 1,057 to 605 cc, respectively.
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The target volume has shrunk from 1,910 to 1,057 cc ( Figures 3A, B ). The overview of the clinical course of this patient is illustrated in  Figure 3D .