Preoperative Imaging with ¹⁸F-FDOPA PET/CT for Small Bowel Neuroendocrine Tumors

Excerpt

A 79-year-old man with a previous past medical history significant for mild arterial hypertension came to our attention for a chronic history of abdominal pain, constipation, and recent vomiting. At physical examination, there was mild abdominal tenderness without guarding, and the abdominal auscultation found metallic, hyper acting bowel sounds. Abdominal contrast-enhanced computed tomography (CT) found a 3-cm hyper vascularized mass located nearby the distal ileum associated with mild dilation of the small bowel (SB). At CT scan, there was a single liver metastasis (LM) into the segment 2 and no peritoneal carcinomatosis. Clinical findings were suspicious for SB neuroendocrine tumor (NET) with a LM; serum value of chromogranine A and 24-h urinary levels of 5-hydroxyindoleacetic acid (5-HIAA) were also elevated to 344 (normal values < 102 μg/l) and to 90.4 (normal values < 39.2 μmol/l), respectively. Abdominal magnetic resonance imaging (MRI) confirmed the presence of a 3-cm LM into the segment 2 with another 14 mm LM into the segment 5. To investigate the possibility of a SB-NET, carbidopa-assisted ¹⁸F-Fluorodihydroxyphenylalanine (¹⁸F-FDOPA) PET/CT was added to the preoperative imaging and distinctly identified the primary SB-NET with mesenteric lymph nodes involvement (Fig. 1) and multiple bilobar LMs (Fig. 2). Surgical exploration found the primary tumor with metastatic mesenteric lymph nodes and 15 LMs. The primary tumor was resected by right colectomy, ileal resection, and mesenteric lymphadenectomy. LMs were treated by left lobectomy and multiple non-anatomical resection and radiofrequency ablation of multiple LMs. Postoperative course was uneventful, and pathology confirmed a 33-mm well differentiated SB-NET (KI-67: 2%) with lymph nodes (2/10) and LMs. The patient was given somatostatin analogues over the long-term.

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