Malignant Tumors

CHAPTER 59

Malignant Tumors

Leukemia

INTRODUCTION/ETIOLOGY/EPIDEMIOLOGY

• Leukemia comprises 25% to 30% of cancer in the pediatric age group.

• It is more common in white children than in Black children.

SIGNS AND SYMPTOMS

• Of children with leukemia, 25% will present with bone pain, usually in the extremities; a few may also report joint pain, swelling, or limp.

• Musculoskeletal symptoms are less common than systemic symptoms, which include fatigue, easy bruising or bleeding, infection, and fever.

• Physical examination may reveal diffuse lymphadenopathy, hepatosplenomegaly, and tenderness to palpation of the affected long bones of the extremities.

• Bruises in multiple stages of healing may also be found.

DIFFERENTIAL DIAGNOSIS

• Laboratory studies and radiographs will differentiate bone pain caused by leukemia from osteomyelitis, septic arthritis, transient synovitis, or primary bone tumor.

DIAGNOSTIC CONSIDERATIONS

• In those with musculoskeletal symptoms, radiographic findings may include

— Osteopenia

— Periosteal reaction

— Metaphyseal bands

— Sclerosis with or without lytic areas

• Complete blood count will show bone marrow failure, usually with anemia and thrombocytopenia.

• Leukemic cells may or may not be seen on a peripheral blood smear.

• Bone marrow biopsy provides definitive diagnosis.

TREATMENT

• Treatment involves chemotherapy.

EXPECTED OUTCOMES/PROGNOSIS

• Prognosis is better for children with the following factors:

— Between 1 and 9 years of age at presentation (with B-cell acute lymphoblastic leukemia [ALL] only)

— White blood cell count less than 100,000 per microliter at presentation

— White race (unknown if this is a physiological or sociological factor)

— Female sex

— Pre–B-cell or early pre–B-cell ALL (vs T-cell and mature B-cell ALL)

— Only one chemotherapy cycle needed to achieve remission

— No spread to liver, spleen, spinal fluid, or testicles

WHEN TO REFER

• Refer immediately to a pediatric oncologist for definitive diagnosis and treatment.

RESOURCES FOR PHYSICIANS AND FAMILIES

• Medscape definition of pediatric acute lymphoblastic leukemia (https://emedicine.medscape.com/article/990113-overview)

Neuroblastoma

INTRODUCTION/ETIOLOGY/EPIDEMIOLOGY

• Neuroblastoma is a cancer of the peripheral sympathetic nervous system, accounting for 8% of cancers in children.

• Most children are diagnosed before 5 years of age.

SIGNS AND SYMPTOMS

• Symptoms include abdominal pain and swelling.

• If metastatic disease is present, children may report bone pain, fever, weight loss, subcutaneous nodules, orbital proptosis, and periorbital ecchymoses.

• Paraspinal lesions may cause back pain with radicular symptoms.

DIFFERENTIAL DIAGNOSIS

• Abdominal rhabdomyosarcoma

• Wilms tumor

DIAGNOSTIC CONSIDERATIONS

• Radiographs of the extremities (obtained for bone pain) are expected to show normal findings in early stages, but later may show lytic bone lesions; an intra-abdominal mass may be seen on radiographs or computed tomography (CT) scans.

• Bone scan will identify metastatic bone lesions.

• Biopsy is usually required for definitive diagnosis.

TREATMENT

• Surgical excision, chemotherapy, and possibly radiation therapy may be indicated.

EXPECTED OUTCOMES/PROGNOSIS

• Depends on age, stage, and certain biologic characteristics of the tumor

— Low-risk localized tumors for which complete excision is possible have a 90% cure rate.

— High-risk tumors carry a less than 50% survival rate.

WHEN TO REFER

• Refer immediately to a pediatric oncologist for definitive diagnosis and treatment.

RESOURCES FOR PHYSICIANS AND FAMILIES

• Medscape definition of pediatric neuroblastoma (https://emedicine.medscape.com/article/988284-overview)

Osteosarcoma

INTRODUCTION/ETIOLOGY/EPIDEMIOLOGY

• Osteosarcoma is the most common primary malignancy of bone in patients younger than 30 years.

• It comprises 56% of all malignant bone tumors.

• Annual incidence is 4.8 per 1 million children

• Incidence is slightly higher in boys than in girls and in Black children than in white children

• Children with a history of hereditary retinoblastoma, Li-Fraumeni syndrome, and Rothmund-Thomson syndrome are at greater risk for an osteosarcoma.

• Osteosarcoma is found in the long bones of the upper and lower extremities and in the central axis (ie, the flat bones of the shoulder, chest, and pelvis and in the soft tissues).

• The distal femur is the most common site, followed by the proximal tibia and proximal humerus.

SIGNS AND SYMPTOMS

• Pain and mass are the most common presenting symptoms.

— Onset of pain is insidious but progressive.

• Can present in any bone, but the distal femur, proximal tibia, and proximal humerus are the most common sites

— Symptoms are typically present for an average of 3 months before the diagnosis is made.

— Twenty percent report nighttime pain.

— Fifty-five percent report intermittent pain at rest.

• At the first visit, 40% have a palpable mass that is typically tender and firm.

• There may be limited range of motion of the adjacent joint.

• Swelling of the affected limb may be noted when a distinct mass is not palpable.

• Paresthesia related to peripheral nerve compression caused by the tumor is rare.

• If a pathologic fracture has occurred, the child may report sudden onset of pain and swelling.

DIFFERENTIAL DIAGNOSIS

• Osteomyelitis

• Symptoms may resemble musculoskeletal injury early in the course of disease; maintain a high index of suspicion for an osteosarcoma in patients whose symptoms persist or worsen despite conservative therapy.

DIAGNOSTIC CONSIDERATIONS

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