Table 1: Suggested algorithm for the treatment and followup from the literature cited in the paper.

Histology:
(i) Scattered staining for chromogranin A and synaptophysin, along with mucus.
(ii) Ki67 index.
(iii) Staging according to Tang et al. [12].
Imaging:
Diagnostic procedures(i) CT/MRI of the chest and the abdomen/pelvis
(ii) MRI of the abdomen/pelvis
(iii) Somatostatin receptor scintigraphy, Ga68-PET scans are usually negative
(iv) FDG-PET and MIBG-PET scannings are usually negative
Biochemistry:
(i) CEA, CA-19-9, CA-125
(ii) Chromogranin A and U-5HIAA usually normal

Appendectomy
Surgical therapyHemicolectomy (standard surgical treatment)
Debulking surgery when possible

Medical therapy5-fluorouracil-based chemotherapeutic regimen
Cytoreductive surgery combined with HIPEC in selected cases

(i) Clinical: abdominal pain, weight loss
Followup(ii) Biochemistry: CEA, CA-19-9, and CA-125
(iii) Imaging: CT or MRI every 3–6 months, then yearly, mimicking the guidelines for colorectal adenocarcinoma. Lifelong followup.