Differential Diagnosis for the 3 mm Nodule
- Single most likely diagnosis
- Benign process (e.g., fibrosis or inflammatory nodule): The nodule has been stable for three years, and its presence was noted shortly after the partial nephrectomy. The fact that it has "matured" over time suggests a benign process.
- Other Likely diagnoses
- Local recurrence of chromophobe RCC: Although the primary tumor was small and low-stage (T1A), there is still a possibility of local recurrence, especially given the nodule's location near the surgical bed.
- Suture granuloma: A small, benign inflammatory reaction to sutures used during the partial nephrectomy, which could present as a small nodule.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Metastatic lymph node: Although the primary tumor was small and low-stage, lymph node metastasis is still a possibility, and missing this diagnosis could have significant consequences.
- Sarcomatoid transformation: Although the primary tumor did not have sarcomatoid features, there is a small chance of sarcomatoid transformation in a recurrence, which would have a poor prognosis.
- Rare diagnoses
- Other primary malignancies (e.g., sarcoma or lymphoma): Although rare, it is possible that the nodule represents a new, unrelated primary malignancy.
- Infectious or inflammatory processes (e.g., abscess or tuberculosis): Uncommon causes of a small nodule in this location, but should be considered in the differential diagnosis.