Differential Diagnosis for Perirenal Lymphadenopathy

Given the patient's recent trip to Thailand and surrounding countries, the differential diagnosis can be organized into the following categories:

• Single Most Likely Diagnosis

  • Tuberculosis (TB): Given the patient's travel history to a region with a high prevalence of TB, and the presentation of perirenal lymphadenopathy, TB is a strong consideration. TB can affect any part of the body, including the lymph nodes around the kidneys, and often presents with lymphadenopathy as an initial symptom.

• Other Likely Diagnoses

  • Lymphoma: Both Hodgkin's and non-Hodgkin's lymphoma can present with lymphadenopathy, including in the perirenal area. While less common than TB in this context, lymphoma is a significant consideration due to its potential for serious morbidity.
  • Infectious Mononucleosis: Caused by Epstein-Barr virus (EBV), infectious mononucleosis can lead to lymphadenopathy, although perirenal involvement is less common. The patient's travel history and potential exposure to different pathogens make this a consideration.
  • Parasitic Infections (e.g., Toxoplasmosis, Leishmaniasis): Given the travel history, parasitic infections that can cause lymphadenopathy should be considered, especially if the patient has been exposed to vectors like sandflies (for Leishmaniasis) or has consumed undercooked meat (for Toxoplasmosis).

• Do Not Miss Diagnoses

  • Malignant Neoplasms (e.g., Renal Cell Carcinoma, Testicular Cancer): Although less likely, it's crucial not to miss a diagnosis of a malignant neoplasm that could be causing perirenal lymphadenopathy. These conditions are potentially life-threatening and require prompt diagnosis and treatment.
  • HIV Infection: HIV can cause lymphadenopathy and is a critical diagnosis not to miss due to its significant implications for patient management and prognosis. The travel history could increase the risk of exposure to HIV, depending on the patient's behaviors and activities during travel.

• Rare Diagnoses

  • Sarcoidosis: A systemic granulomatous disease that can cause lymphadenopathy, including in the perirenal area, although this is a rare presentation. Sarcoidosis is less likely but should be considered if other diagnoses are ruled out.
  • Castleman Disease: A rare disorder that involves an overgrowth of cells in the body's lymph nodes, which can cause lymphadenopathy. It's a rare condition but could be considered in the differential diagnosis if more common causes are excluded.

Each of these diagnoses requires careful consideration of the patient's travel history, exposure risks, and clinical presentation. A thorough diagnostic workup, including imaging studies, laboratory tests, and potentially biopsy, will be necessary to determine the underlying cause of the perirenal lymphadenopathy.