Differential Diagnosis for a Rapidly Growing Soft Tissue Mass in the Orbit of a 2-Year-Old Girl

• Single Most Likely Diagnosis
  • Rhabdomyosarcoma: This is the most common primary malignant orbital tumor in children, often presenting with rapid growth and proptosis. Its aggressive nature and the patient's age make it a prime consideration.
• Other Likely Diagnoses
  • Neuroblastoma: Although more commonly associated with the adrenal glands, neuroblastoma can originate from any sympathetic nervous tissue, including the orbit, and cause proptosis.
  • Orbital cellulitis: An infection of the orbital tissues, which can cause rapid swelling and proptosis, although it typically presents with significant pain, redness, and fever.
  • Capillary hemangioma: A benign vascular tumor that can grow rapidly in infancy and early childhood, potentially causing proptosis if located in the orbit.
• Do Not Miss Diagnoses
  • Metastatic disease: Although rare, certain cancers like neuroblastoma can metastasize to the orbit, making it crucial to consider in the differential diagnosis to ensure timely and appropriate treatment.
  • Lymphoma: Both Hodgkin's and non-Hodgkin's lymphoma can involve the orbit, and given the potential for aggressive disease, missing this diagnosis could have significant consequences.
• Rare Diagnoses
  • Fibromatosis (desmoid tumor): A rare, locally aggressive fibrous tumor that can occur in the orbit and cause proptosis.
  • Teratoma: A rare tumor that can contain several different types of tissues and, if located in the orbit, could cause proptosis.
  • Orbital granulocytic sarcoma (chloroma): A rare extramedullary tumor associated with myeloid leukemia, which can present as an orbital mass.