# Subcutaneous Lanreotide Depot: A Diagnostic Pitfall in Neuroendocrine Tumor Imaging

## TL;DR

This paper highlights how lanreotide depot, a treatment for neuroendocrine tumors, can be mistaken for metastatic lesions on imaging, leading to potential misdiagnosis.

## Contribution

The paper presents a case showing how lanreotide depots can be misinterpreted as metastases, emphasizing the need for diagnostic awareness.

## Key findings

- Persistent lanreotide depots can mimic metastatic lesions on CT scans.
- Retrospective imaging analysis helped correctly identify the depots as treatment-related.
- The case highlights the importance of recognizing this diagnostic pitfall to avoid unnecessary interventions.

## Abstract

Lanreotide depot, a long-acting somatostatin analog, improves progression-free survival in neuroendocrine tumor (NET) patients. However, persistent subcutaneous depots can appear as metastatic lesions on imaging, potentially leading to misdiagnosis. We report the case of a 70-year-old man with grade 2 NET (Ki-67: 5.9%) undergoing six years of lanreotide treatment. Follow-up imaging revealed stable primary disease. However, nodular lesions in the buttock were identified on the CT scan performed eight months after the start of treatment. A retrospective review of a CT scan taken two months after treatment initiation revealed that these nodules were already present and had gradually increased in number, allowing for their correct identification as persistent lanreotide depots. This case underscores the need for heightened diagnostic awareness to prevent unnecessary interventions and ensure accurate management.