Goblet cell carcinoid, now goblet cell adenocarcinoma, masquerading as acute appendicitis: Case report of an uncommon clinical presentation and a brief review of the literature

A goblet cell carcinoid (GCC) is an appendiceal neoplasm with mixed neuroendocrine and glandular differentiation that is uncommon and most typically affects middle-aged adults. The terminology of this tumor has recently been changed to goblet cell adenocarcinoma (GCA) to indicate the malignant behavior of this tumor, which is more than that of a neuroendocrine tumor (NET). The WHO has removed the term “carcinoid” in naming tumors in its 2022 classification.

In this report, we present a 42-year-old man who was admitted to the hospital with complaints of severe pain in the right lower abdomen, fever, and elevated white blood cells, which were the common symptoms of acute appendicitis. He had a scheduled appendectomy and thought that he would recover like any other normal case. However, what was unexpected was the pathology report, which showed goblet cell adenocarcinoma (GCA), a rare and aggressive tumor that was previously known as GCC. In contrast to the general NETs, GCC acts rather like an adenocarcinoma, inclining to invade the adjacent tissues and metastasize. Here, the tumor has extended beyond the appendix and invaded the surrounding fat (T3N0M0, Stage IIA). The fat invasion also necessitated continued treatment, whereas the lymph nodes and distant organs were not affected. The carcinoid/adenocarcinoma terminology transformation signifies the actual nature of the tumor, which is more of a rapidly progressing cancer that needs vigorous treatment rather than a NET with a slow growth rate.

This case serves as a reminder to keep a wide differential diagnosis, even in classical presentations, such as appendicitis. Cross-disciplinary tumor board discussion was key in decision-making regarding the treatment plan. Four years after surgery, the patient is still disease-free. We provide a brief literature review on this uncommon tumor and clarify the recent change in classification terminology.