[Musculoskeletal involvement as a first manifestation of neoplasm disease]

To describe the clinical and laboratory findings that contributed for the diagnosis of neoplasia in patients with musculoskeletal symptoms at presentation.

Retrospective analysis of medical records from patients with final diagnosis of neoplasia attended at the "Unidade de Reumatologia do Instituto da Criança - FMUSP" between January 1983 and December 2006. Data on musculoskeletal complaints, clinical examination, laboratory tests, radiological studies and diagnostic procedures were obtained.

From 4876 patients, 25 (0.5%) children were studied (52% with acute lymphoid leukemia and 24% with neuroblastoma). Twenty children (80%) presented arthritis and/or arthralgia at onset of the disease. All patients presented systemic symptoms, such as fever (22 cases - 88%). The initial blood cell count was abnormal in 16 patients (64%), showing anemia and thrombocytopenia (12 and 5 cases, respectively). Blast cells were present in only two patients and eleven patients developed blood cell count abnormalities during follow-up. X-ray studies showed abnormalities in 11/14 patients, ultrasound in 12/18, scintigraphy in 5/5, CT in 7/9 and MRI in 3/3. Bone marrow smear was abnormal in 18/22 patients, but in three of them the abnormalities were not detected by the first test.

Musculoskeletal symptoms are common at the onset of neoplasia, especially for acute lymphoid leukemia, and this possibility should be considered in the differential diagnosis of rheumatic diseases. Laboratory tests may be normal at the onset of the disease, therefore serial exams should be performed. For a correct diagnosis. radiological studies and bone marrow aspiration have proven to be essential.