Introduction:
Goblet cell carcinoid (GCC) is a rare neoplasm of the vermiform appendix. A histopathological examination is vital as there are no obvious macroscopic features identifiable during surgery for a “suspected appendicitis”. Due to its rarity, it may be misinterpreted as neuroendocrine tumor.
Case Report:
We report a 37-year-old male diagnosed histopathologically as appendiceal neuroendocrine tumour after undergoing an appendicectomy when he presented with acute appendicitis. He was referred to our institution for further management of NET.
Re-examination of the slides by our histopathologist reported the specimen as a mixed neuroendocrine-non-neuroendorine neoplasm (MiNEN) of intermediate grade (goblet cell carcinoid) as there were two morphologically distinct tumour components. The conventional group, composing of nests and cords of tumour cells, exhibited round uniform nuclei with salt and pepper chromatin and scanty eosinophilic cytoplasm (NET appearance). The second group of cells displayed irregular infiltrating nests of goblet cells with abundant univacuolated cytoplasm and peripheral compressed nuclei. Both tumour groups encompass >30% of tumour volume each. Mitotic figures were not seen. Immunohistochemical studies showed both tumour groups being positive to synaptophysin and chromogranin. Only the goblet group shows positivity to CK20. Ki-67 proliferation index is <2%.
Based on the HPE we classified the patient as Tang’s classification group A (classic GCC). He decided to undergo right hemicolectomy subsequently and the histopathological examination showed no local invasion. The patient is currently well postoperatively and is scheduled for a FDG-PET scan for further staging.
Conclusion:
GCC tumours are more aggressive than classical neuroendocrine tumours even if they do not exhibit malignant properties of adenocarcinomas. Thus, they should be identified promptly as their further definitive therapy differs from adenocarcinoma or NETs.