Childhood acute lymphoblastic leukemia presenting as "cold" lesions on bone scan: a report of two cases

Splenic Uptake in 99 mTc-Methylene Di-Phosphonate Scan in a Pediatric Patient with Acute Lymphocytic Leukemia

An 12-year-old boy with relapse of acute lymphocytic leukemia and suspected skeletal involvement underwent mTc-Methylene Di-Phosphonate skeletal scintigraphy, which revealed a lytic “cold” lesion in the pelvis and diffuse splenic uptake. There was no active splenic infiltration in cross-sectional imaging. However, the patient had a history of multiple blood transfusions, which is a rare cause for diffuse splenic uptake.

[Differential diagnosis of reduced uptake images revealed by bone scan: about a case of acute lymphoblastic leukemia]

If increased uptake during bone scan usually bring to light many bone pathologies, reduced uptakes are a rare occurrence and they require careful analysis to avoid erroneous interpretations. We report the case of a 17-year old admitted with diffuse bone pain, hypercalcemia and thrombopenia. Bone scan showed areas of low uptakes. Bone marrow tests allowed the diagnosis of acute lymphoblastic leukemia. This case report aims to discuss the main differential diagnoses based on such bone scan abnormalities.

Musculoskeletal problems in pediatric acute leukemia

Acute leukemia (AL) in children can mimic several orthopedic pathologies at presentation, with a variable delay in the correct diagnosis. This is a major problem, which may result in fractures, loss of mobility, and deformity, with resultant adverse effects on quality of life. Here, we studied the clinical and radiological musculoskeletal manifestations in children with AL. We reviewed 328 children [208 boys (62%), median age 7.2 years] with acute lymphoblastic (279, 85%) or myeloid (49, 15%) leukemia, treated between January 1982 and December 2003 by the Paediatric Oncology Service, Second University of Naples. The group was further divided into two groups: group 1 included 255 patients (78%, 163 boys) without skeletal morbidity at diagnosis, and group 2 included 73 patients (22%, 41 boys) with musculoskeletal symptoms. This group was further subdivided into group 2A (56 patients), which included children with symptoms related to the appendicular skeleton, and group 2B (17 patients), which included children with symptoms related to the axial skeleton. Moreover, we also reported the long-term complications of therapy, such as osteonecrosis of the weight-bearing joints. In group 2A, 44 children presented only pain, seven septic arthritis-type symptoms, and five osteomyelitis-type symptoms. Joint compression was in the tibia-tarsus (21 patients), knee (16), coxofemoral (12), and elbow (seven). In group 2B, 11 patients presented with vertebral collapses. The remaining six patients complained of localized pain in the lumbar-sacral area, with limited flexor and extensor muscle capacity. Fifty-five (75.3%) patients showed radiographic abnormalities: osteoporosis in 22 patients (40%), pathological fractures in 11 (20%), osteolysis in 10 (18.1%), osteosclerosis in five (9%), periosteal reactions in four (7.2%), and metaphyseal bands in three (5.4%). Four (1.2%) patients in total showed avascular necrosis (4.3% when only high-risk patients were considered). At presentation, 22% of our children had at least one musculoskeletal manifestation and 75.3% showed one radiographic change. Our study highlights the importance of including AL in the differential diagnosis of musculoskeletal manifestations. Four cases of avascular necrosis confirm the need for regular check-ups, both orthopedic and nonorthopedic, particularly in adolescent girls, to prevent permanent disability.

Pediatric leukemia revealed by a limping episode: a report of four cases

Acute limping in children is a common reason for consultation in pediatric emergency units. Acute leukemia is a rarely encountered disease in the orthopedic surgeon's activity. In addition, its clinical presentation is not typical and therefore is a source of possible diagnostic delay. For such reasons, there is a definite risk of undiagnosing the actual etiology of the limping episode. We report our experience with four cases of children initially seen in the pediatric emergency department for limping, as their revealing presentation of acute leukemia. The limb pain was highly variable. The radiographic work-up was always normal. Peripheral blood abnormalities were initially absent in one case and blastic cells were absent in two cases. The physician in charge should remember that paraclinical work-up normal results do not exclude a diagnosis of acute leukemia, that any drop in hematopoietic cell counts should call for a myelogram and that paraclinical exams, including the hemogram, should be repeated until a diagnosis and improvement or confirmed cure is achieved over time.