Differential Diagnosis for a 199 mm Hard Painful Non-Movable Nodule in the Right Femoral Lymph Node in a 4-Year-Old

• Single Most Likely Diagnosis
  • Lymphoma: Given the age of the patient and the presentation of a hard, painful, and non-movable lymph node, lymphoma is a strong consideration. Lymphomas can present with lymphadenopathy, and the femoral region, although less common, can be involved. The size and characteristics of the nodule, along with the patient's age, make lymphoma a leading diagnosis.
• Other Likely Diagnoses
  • Infection (e.g., Tuberculosis, Cat Scratch Disease): These can cause lymphadenopathy, which may be painful and hard. The non-movable nature could be due to matting of nodes or inflammation.
  • Metastatic disease (e.g., Neuroblastoma, Rhabdomyosarcoma): Although less common, certain pediatric cancers can metastasize to lymph nodes, presenting as hard, fixed masses.
• Do Not Miss Diagnoses
  • Malignant histiocytosis: A rare but aggressive condition that can mimic lymphoma and requires prompt diagnosis.
  • Leukemia: Although leukemia typically presents with systemic symptoms, it can occasionally manifest with lymphadenopathy.
• Rare Diagnoses
  • Kikuchi-Fujimoto disease: A rare, self-limiting condition that can cause lymphadenopathy, more commonly seen in the neck but can occur elsewhere.
  • Kimura disease: A chronic inflammatory disorder that can cause lymphadenopathy and eosinophilia, more common in Asian males but can occur in other populations.
  • Castleman disease: A rare disorder that can cause lymphadenopathy, which can be localized or multicentric, and has different subtypes with varying prognoses.

Each of these diagnoses has a different approach to management and treatment, emphasizing the importance of a thorough diagnostic workup to determine the underlying cause of the lymph node enlargement.