Differential diagnosis of pediatric chest wall masses

Organ of origin from outside in:

• Skin – Pilomatricoma
• Subcutaneous fat – Lipoma, Lipoblastoma, Liposarcoma
• Muscle – Infection / abscess, Hematoma, Fibromatosis, Fibromatosis colli, Fibrosarcoma, Rhabdomyosarcoma, Malignant fibrous histiocytosis
• Bone / cartilage – Protuberant rib / cartilage, Bifid rib, Tilted sternum, Osteomyelitis, Osteochondroma, Enchondroma, Aneursymal bone cyst, Osteoid osteoma, Mesenchymal hamartoma of chest wall, Ewing sarcoma, Osteosarcoma, Langerhans cell histiocytosis
• Blood vessels – Vascular malformation (hemangioma)
• Lymphatics – Lymphatic malformation, Lymph node, Lymphoma
• Nerves – Plexiform neurofibroma, Malignant peripheral nerve sheath tumor
• Pleura – Benign fibrous mesothelioma
• Metastases – Bone (Neuroblastoma), Muscle (Rhabdomyosarcoma, Lymphoma [Hodgkin, Non-Hodgkin, Burkitt]), Soft tissues (Leukemia, Neuroblastoma)

Approach to the differential diagnosis of chest wall masses:

• Use ultrasound to try to determine organ of origin of mass from the outside in and whether it has a classic appearance
  • Skin – Pilomatricoma
  • Muscle – Infection / abscess, Hematoma
  • Bone / cartilage – Rib / cartilage anomaly
  • Blood vessels – Vascular malformation
  • Lymphatics – Lymphatic malformation, Lymph node
• Otherwise the lesion is non-specific in appearance and a sarcoma cannot be ruled out
  • Consider MRI for further soft tissue definition