Differential Diagnosis
- Single most likely diagnosis
- Benign lymph node or non-specific finding: The fact that the nodule has not grown in 3 years and has only become more defined suggests a benign nature. The small size of the nodule (3mm) also makes it less likely to be a metastatic lymph node.
- Other Likely diagnoses
- Reactive lymph node: The nodule's location and stability in size over time could indicate a reactive lymph node, which is a common finding in the retroperitoneum.
- Fibrotic or inflammatory change: The nodule's appearance and lack of growth could be consistent with a fibrotic or inflammatory change, possibly related to the previous surgery.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Single metastatic lymph node from the primary cancer: Although the stability in size and long duration since the primary cancer make this less likely, it is crucial not to miss a potential metastasis. Chromophobe RCC can metastasize, and a single lymph node metastasis would significantly impact treatment and prognosis.
- Lymphoma: Although rare, lymphoma could present as a solitary lymph node, and it is essential to consider this diagnosis to avoid missing a potentially curable condition.
- Rare diagnoses
- Other primary malignancies (e.g., lymph node metastasis from a different primary cancer): The possibility of a new primary cancer metastasizing to a lymph node in this location, although rare, should be considered.
- Infection or granulomatous disease: Rarely, infections like tuberculosis or granulomatous disease could present as a solitary lymph node, and this diagnosis should be considered in the appropriate clinical context.