We thank Dr. Teco-Cortes for his Letter to the Editor1 and his comments on our Scientific Letter entitled “Neuroendocrine tumor of the ileum: The outcome of an untimely diagnosis”.2 His feedback enriches the discussion on the correct classification and terminology of neuroendocrine neoplasms.

We agree with the author that neuroendocrine neoplasms can occur in multiple organs that are not strictly part of the classic neuroendocrine system, including the respiratory tract and the genitourinary system, reflecting the wide distribution of cells with neuroendocrine differentiation across diverse tissues.

Regarding the observation on the use of the term “neuroendocrine pattern”, we acknowledge that, from a strictly histopathologic perspective, the more appropriate term is “neuroendocrine differentiation”, whereas growth patterns describe tumor architecture, such as organoid, trabecular, or nested arrangements. In our article, we used the term in a descriptive sense, based on the original histopathologic report.3

Concerning the current classification of neuroendocrine neoplasms proposed by the World Health Organization, we agree on the importance of distinguishing between well-differentiated neuroendocrine tumors (G1, G2, and G3) and poorly differentiated neuroendocrine carcinomas, given that the distinction has fundamental diagnostic, prognostic, and therapeutic implications.3

The primary purpose of our report was to highlight the diagnostic challenge that small bowel tumors may represent in clinical practice. Said neoplasms are relatively uncommon and their identification through conventional diagnostic methods, such as endoscopy and imaging studies, may be particularly complex. In the case we presented, the patient had previously undergone numerous colonoscopies, contrast-enhanced tomography scans, and even an enteroscopy, without achieving a conclusive diagnosis. Not until the acute presentation of intestinal obstruction and the subsequent surgical intervention was the definitive diagnosis able to be made.

We recognize the importance of the proper histopathologic classification, especially considering the therapeutic differences between well-differentiated neuroendocrine tumors and neuroendocrine carcinomas. However, in the context of our patient’s acute disease presentation, the initial surgical intervention was necessary and was performed following oncologic principles, in accordance with the technical and surgical possibilities of our unit. The patient subsequently continued his medical oncologic follow-up, starting systemic treatment with cisplatin and capecitabine, coinciding with the point raised by Dr. Teco-Cortes regarding the differences in the therapeutic regimens between these entities.

The patient is currently in medical oncologic follow-up, with no signs of disease, and underwent bowel transit restoration two months ago.

We consider that our case emphasizes the importance of maintaining a high degree of clinical suspicion in patients presenting with chronic abdominal pain or nonspecific gastrointestinal symptoms, particularly when initial studies do not identify a clear etiology. Likewise, it underlines the relevance of adequate classification of these neoplasms through the corresponding immunohistochemical studies. We recognize that there could have been limitations in this respect in our case, related to reagent availability and institutional experience in the management of these uncommon conditions.

Finally, we believe there are important opportunities for clinical research in this field, particularly in relation to the diagnostic difficulties regarding small bowel neoplasms. We agree on the relevance of the topic and feel that it could be a valuable area for developing future collaborative research among our institutions, promoting the interaction between surgery, pathology, and oncology services, as well as with national referral centers that can aid in resolving the complex diagnostic challenges for secondary care hospital units.

Once again, we appreciate the observations made, as they contribute to strengthening the accuracy in terminology and the academic discussion surrounding this group of neoplasms.