Bone and soft tissue tumors are uncommon in the general population and are even more uncommon in the upper extremity in children. Although not often seen, it is helpful for the practicing orthopedic surgeon to have a basic knowledge of the types of tumors which can be encountered in this setting and their usual presentation.
Benign Bone Tumors
Osteochondromas
Osteochondromas are the most common benign bone tumor. This tumor is frequently diagnosed in the first two decades of life. When in the upper extremity, the most common locations are the proximal humerus and scapula. Osteochondromas usually present as a painless hard mass. The radiographic features are that of a bony projection with a cortex that continues with the underlying bone. On MRI, the marrow of the osteochondroma is continuous with that of the normal adjacent marrow. Histology reveals a cartilaginous cap adjacent to a bony stalk. These lesions frequently will grow in conjunction with normal skeletal growth. Treatment is usually observation unless they are symptomatic, causing deformity, or there is concern regarding malignancy.
Enchondromas
Enchondromas may often be diagnosed in the first two decades of life. When in the upper extremity, the most common location is in the hand. On radiographs, these typically asymptomatic lesions usually appear as a localized region of rarefaction with areas of calcification. Histologically, they are composed of hyaline cartilage usually in a lobular arrangement. These tumors rarely require treatment and can usually be followed, especially in children where the occurrence of a malignant cartilage tumor is less likely than in an adult. A fracture through an enchondroma of the phalanges is typically treated by immobilization until healing occurs, followed by curettage and bone grafting.
Chondroblastomas
Chondroblastomas usually occur in the second or third decade of life. This lesion is usually painful and when in the upper extremity, typically presents as a well-defined, lytic, oval or round defect in the epiphysis of the proximal humerus (shoulder).
Histologically, chondroblastomas appear as collections of oval-shaped mononuclear cells surrounded by lace-like calcification. Treatment is usually curettage and bone grafting.
Osteoid Osteomas
Osteoid osteomas frequently occur in the second, and occasionally first decade of life. This tumor typically produces pain, which is relieved with salicylates. Although more common in the lower extremity, osteoid osteomas may affect the upper extremity without a real predilection for any particular location. Radiologically, they appear as a small radiolucent nidus surrounded by a zone of sclerosis. The histology of the nidus is composed of bony trabeculae surrounded by vascular connective tissue.
Aneurysmal Bone Cyst
ABCs may occur in the first and second decades of life, and typically presents with pain and swelling. These lesions can occur throughout the upper extremity, without a particular predilection for site. Radiographically, they present as a lytic expansile lesion with periosteal reaction which may be mistaken for a malignant tumor. Histologically, ABCs appear as highly vascular lesions with a stroma of benign-appearing spindle cells. A 12-year-old female presented with pain and swelling in the left humerus. Radiographs demonstrated a lytic appearing lesion in the diaphysis of the humerus with evidence of periosteal reaction. MRI was performed revealing an aggressive appearing soft tissue component. Biopsy was performed which revealed an ABC. Definitive treatment was by curettage and bone grafting.
Eosinophilic Granuloma
Eosinophilic granuloma frequently occurs in the first and second decades of life and may occur in the upper extremity. Radiographically, eosinophilic granuloma may appear as a poorly marginated lytic lesion with periosteal reaction in the early stage, and have a more sclerotic well-defined margin in the late stage. Histologically, they contain eosinophils and mononuclear histiocytes. Solitary lesions usually resolve after curettage. An 11-year-old male presented with pain and swelling in his left clavicle. Radiographs demonstrated an infiltrative, ill-defined lesion in the area of the distal clavicle (Slide 2A). MRI also demonstrated this lesion, which had a minimal soft tissue component, with decreased signal on T1 and bright signal on fast spin echo (Slide 2B and Slide 2C). Biopsy revealed eosinophilic granuloma. Following biopsy this lesion was observed and resolved spontaneously over a period of several months.
Malignant Bone Tumors
Osteosarcoma
Osteosarcoma frequently occurs in the second decade of life, where it usually presents with pain and a soft tissue mass. The upper extremity is not an uncommon location for osteosarcoma where it often involves the proximal humerus. Radiographically, osteosarcomas usually appear as destructive, permeative lesions with soft tissue extension. Histologically, they have proliferating malignant-appearing cells producing osteoid. Treatment is chemotherapy and surgery. A 17-year-old female presented with pain and swelling in the area of her right forearm. Radiographs demonstrated a lytic destructive lesion of the diaphysis of the right radius with ill defined borders (Slide 3A). Bone scan demonstrated increased uptake in this area as would be expected (Slide 3B). There were no other lesions identified. MRI also demonstrated this tumor which had extended into the soft tissue (Slide 3C). Biopsy demonstrated a high grade osteogenic sarcoma. Treatment was with chemotherapy followed by surgical resection and then further chemotherapy. Reconstruction involved conversion to a one-bone forearm.
Ewing Sarcoma
Ewing sarcoma usually occurs in the first and second decades of life. These tumors typically present as a diaphyseal or metaphyseal lytic permeative lesion which usually has extensive periosteal reaction, often in an "onion skin" appearance. When in the upper extremity, these tumors are most common in the humerus and scapula. Histologically, they appear as a collection of round, small, blue cells. Treatment always involves chemotherapy. Most centers treat resectable lesions with surgical excision. Currently, the use of radiation versus surgery, alone or in combination is being investigated.