Differential Diagnosis
- Single most likely diagnosis
- Post-surgical change or scar tissue: This diagnosis is most likely due to the radiologist's opinion that the 3mm nodule has "matured" over the past 3 years and become more defined, and the fact that it was present on previous scans but not as visible due to lower resolution.
- Other Likely diagnoses
- Reactive lymph node: Although the second opinion from the surgeon/urologist/ oncologist stated that the location is not within the lymphatic pathway, it is still possible that the nodule could be a reactive lymph node, especially given its small size and stable appearance over time.
- Benign fatty lesion: The biopsy of the 1.5cm soft tissue mass adjacent to the surgical bed showed fibroadipose tissue with focal macrophages and chronic inflammation, and it is possible that the 3mm nodule could be a similar benign fatty lesion.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed)
- Metastatic lymph node: Although the surgeon/urologist/oncologist stated that the location is not within the lymphatic pathway, it is still important to consider the possibility of a metastatic lymph node, especially given the patient's history of renal cell carcinoma.
- Local recurrence of renal cell carcinoma: The fact that the nodule is located near the surgical bed and has been present for several years raises the possibility of a local recurrence, although the stable appearance over time makes this less likely.
- Rare diagnoses
- Other malignant tumors (e.g. lymphoma, sarcoma): Although rare, it is possible that the 3mm nodule could be a separate malignant tumor, and this possibility should be considered in the differential diagnosis.
- Infectious or inflammatory process: The presence of chronic inflammation in the biopsy of the 1.5cm soft tissue mass raises the possibility of an infectious or inflammatory process, although this is less likely given the stable appearance of the nodule over time.