markers, pain, and swelling over the involved bone Benign tumors of bone account for half of the bone tumors in children and include giant cell tumor, eosinophilic granuloma, and aneurysmal bone cysts Benign lesions usually have smooth, welldefined borders on plain radiographs and rarely have associated soft tissue masses Symptoms of malignant bone lesions commonly include pain at the tumor site (in 80% to 90% of cases), soft tissue swelling, and/or a painful limp The pain may wake the patient at night in some cases (less than 25%) FIGURE 98.3 Two plain radiographs demonstrating osteosarcoma of the distal femur Clinical Assessment Diagnostic evaluation in the ED should include a thorough history and physical examination Though there is frequently a history of trauma in retrospect, pain may be intermittent and nondescript for weeks or months Constitutional symptoms or signs, such as fever, fatigue, and weight loss may occur with Ewing sarcoma/PNET If tumor is present in an extremity, a hard mass may be felt Osteosarcoma usually involves the metaphyseal end of long bones, most commonly around the knee or proximal humerus Ewing can occur in any bone but tends to involve the diaphysis when in a long bone An extremity with a bony mass should be completely examined with careful attention to pulses, perfusion, range of motion, and sensation Compartment syndrome may develop due to swelling or bleeding within the mass Pelvic lesions often produce no specific physical findings Lesions of the vertebral body may evoke neurologic symptoms such as neuropathic pain or cord compression In this setting, a careful history of bowel and bladder function should be taken and a thorough neurologic examination performed Any focal neurologic deficits should prompt immediate imaging of the spinal cord to determine if compression is present Laboratory evaluation should include a CBC, evaluation of renal and liver function, inflammatory markers, and serum LDH Diagnostic imaging should begin with a plain radiograph of the affected region for characteristics concerning for tumor, as well as to assess for the presence of a pathologic fracture Characteristic findings of primary bone tumors include a lytic lesion with cortical destruction Early changes include loss of soft tissue fat planes and periosteal elevation (Codman triangle), which has been associated with osteosarcoma Over time, an “onion skin” periosteal reaction develops, caused by repetitive episodes of the lesion pushing out the periosteum and followed by the periosteum responding by laying down calcium This finding has been associated with Ewing sarcoma Neither finding is specific With osteosarcoma, the associated soft tissue mass is sometimes ossified in a radial or “sunburst” pattern Benign bone tumors such as eosinophilic granuloma, aneurysmal bone cysts, and giant cell tumor of bone can present as lytic lesions that tend to have smooth, well-defined borders Plain films should always be assessed for the presence of a pathologic fracture A large lesion with a thin cortex in a weightbearing bone may require immediate immobilization to prevent pathologic fracture Management Often patients with bony masses can be discharged with follow-up securely arranged with an orthopedic surgeon with oncology expertise or a pediatric oncologist for further diagnostic workup and initiation of appropriate therapy An improperly performed biopsy may interfere with subsequent limb-sparing surgery A plan for analgesia should be established prior to discharge Patients with tumors affecting the lower extremities should refrain from bearing weight on the affected limb so as to avoid causing a pathologic fracture Inpatient management is appropriate for pain control or in the presence of cord compression or compartment syndrome TUMORS OF THE SOFT TISSUES Tumors of the soft tissues present the clinician with a diagnostic challenge Many of these lesions are benign Rhabdomyosarcoma is the most common STS in children There are many other types of STS that collectively account for less than 1% of all pediatric cancer They can arise in any anatomic location because connective tissue is located throughout the body Masses are frequently painless and asymptomatic Any presenting symptoms are usually due to local nerve invasion leading to pain or weakness Systemic symptoms are rare The histologic variants of rhabdomyosarcoma tend to have characteristic presentations Botryoid tumors tend to grow in potential spaces such as the bladder and vagina Embryonal tumors often occur in the GU tract, orbit and head, neck, and parameningeal locations Alveolar tumors often present in the extremities and have a worse prognosis Rhabdomyosarcoma can metastasize to local lymph nodes, lungs, bone, and rarely bone marrow There are many benign causes of soft tissue masses in children but the emergency clinician needs to consider cancer as a possible cause Diagnostic evaluation should include a thorough history and physical examination The history should focus on symptoms caused by the mass and other systemic or constitutional symptoms that may be present When a reasonable suspicion for cancer exists, laboratory evaluation should include a CBC, renal and liver function tests, and serum LDH A plain radiograph of the affected area can be useful to look for bone destruction or fracture from an underlying bone lesion A true soft tissue mass, however, is best imaged with an MRI Often patients can be discharged with follow-up securely arranged with a pediatric oncologist for further diagnostic workup and initiation of appropriate therapy Inpatient management may be needed for pain control or if cord compression complicates the presentation CANCERS OF THE SKIN Primary cancers of the skin, such as squamous or basal cell carcinoma or melanoma, are seen in the adult practice setting but rarely occur in children Melanoma accounts for less than 3% of all childhood malignancies but occurs occasionally in adolescents 15 to 19 years old There may be increased risk in the setting of immunosuppression, immunodeficiencies, history of radiation therapy or stem cell transplant, giant congenital nevi, giant congenital melanocytic nevi, or xeroderma pigmentosum Other pediatric cancers may involve the skin, such as leukemia, which may produce leukemia cutis (particularly in infant ALL or in AML) A rash may be part of the presentation of histiocytic disorders, such as HLH or LCH Neuroblastoma does not affect the skin but may present with subcutaneous pigmented nodules visible through the skin Management in the ED should begin with a thorough history and physical examination The examination should be used to screen for other skin lesions, lymphadenopathy, hepatosplenomegaly, masses, or other signs of malignancy that might be related to the skin findings If the history and physical examination suggest a particular diagnosis, then further laboratory or radiographic evaluation may be helpful If not, and if the patient appears to be stable without signs or symptoms of systemic illness, then the patient can be discharged to home with follow-up secured with either oncology or dermatology When cancer is suspected, a biopsy will aid in the diagnosis and involvement from a dermatopathologist with pediatric experience will be essential Some melanocytic lesions in children may appear malignant to pathologists without sufficient experience with the pediatric population  ... dermatopathologist with pediatric experience will be essential Some melanocytic lesions in children may appear malignant to pathologists without sufficient experience with the pediatric population... in children There are many other types of STS that collectively account for less than 1% of all pediatric cancer They can arise in any anatomic location because connective tissue is located throughout... bone, and rarely bone marrow There are many benign causes of soft tissue masses in children but the emergency clinician needs to consider cancer as a possible cause Diagnostic evaluation should include