Differential Diagnosis for Heterogeneous T2 Mixed Signal Intensity, Exophytic Subcapsular Complex Mass

• Single Most Likely Diagnosis
  • Renal Cell Carcinoma: This is the most likely diagnosis due to the description of a heterogeneous T2 mixed signal intensity and an exophytic subcapsular complex mass, which are characteristic features of renal cell carcinoma on MRI. The exophytic nature and complex appearance suggest a malignant process.
• Other Likely Diagnoses
  • Angiomyolipoma with Hemorrhage: Although typically benign, an angiomyolipoma with hemorrhage can present as a complex mass with heterogeneous signal intensity due to the presence of fat, smooth muscle, and blood products.
  • Renal Abscess: A renal abscess can appear as a complex fluid collection with heterogeneous signal intensity, especially if there are locations or debris within the abscess.
  • Cystic Nephroma: This rare benign tumor can have a complex appearance with cystic and solid components, potentially mimicking a malignant process.
• Do Not Miss Diagnoses
  • Metastasis: Although less common, metastatic disease to the kidney can present as a complex mass and must be considered, especially in patients with a known primary malignancy.
  • Lymphoma: Renal involvement by lymphoma can manifest as a complex mass, and it is crucial to consider this diagnosis due to its implications for treatment and prognosis.
  • Inflammatory Pseudotumor: This rare condition can mimic a malignant tumor on imaging but is actually a benign inflammatory process.
• Rare Diagnoses
  • Renal Medullary Carcinoma: A rare and aggressive malignancy that can present with a complex mass, often associated with sickle cell trait.
  • Juxtaglomerular Cell Tumor: A rare benign tumor that can have a complex appearance due to its vascular nature and potential for hemorrhage.
  • Leiomyosarcoma: A rare malignant tumor of smooth muscle origin that can occur in the kidney and present as a complex mass.