Swollen Digits: An Unusual Manifestation of Childhood Acute Lymphoblastic Leukemia

A 6-year-old boy presented with fever and painful swelling of his hands for the past 10 months. He had been diagnosed with osteomyelitis and managed with antibiotics. He had received a packed red cell transfusion for anemia. Findings of the physical examination revealed pallor, generalized lymphadenopathy, and splenomegaly. The fingers and dorsum of the hands were swollen and tender. A radiograph of his hands demonstrated bilateral multifocal osteolytic lesions involving the phalanges (Figure). Complete blood count showed anemia, thrombocytopenia, and lymphocytic predominance in the differential leukocyte count. A bone marrow examination established the diagnosis of acute leukemia. Flow cytometry performed on the bone marrow aspirate confirmed the diagnosis of precursor-B lineage acute lymphoblastic leukemia (ALL).

Figure.

The fingers and dorsum of the hands were swollen and tender. Radiograph of bilateral hands (anteroposterior view) demonstrated multifocal osteolytic lesions involving the middle phalanges of the right fourth and fifth digits, and the left second digit (white arrows). Osteolytic lesions also were seen in the left distal ulna and left second metacarpal with presence of periosteal reaction in these bones (black arrows).

Up to one-third of children with ALL present with musculoskeletal manifestations.¹ Delay in diagnosis and initiation of chemotherapy can occur subsequent to misdiagnosis as osteomyelitis, septic arthritis, and juvenile rheumatoid arthritis.² Pain disproportionate to physical signs of inflammation, nocturnal pain, poor response to conventional analgesics, pain not restricted to the joints, and blood cytopenias are clues to an underlying malignancy.³ Children with ALL presenting with musculoskeletal manifestations are likely to have lesser extramedullary involvement, circulating peripheral blood blasts, and leukocyte counts, in comparison with other children with ALL.¹ Musculoskeletal presentation is more common with precursor-B ALL.¹ Radiologic findings in ALL include metaphyseal leukemic lines, osteolytic lesions, periosteal new bone formation, and osteoporosis.⁴ Dactylitis with involvement of the phalanges akin to our index case is an unusual manifestation of childhood ALL. Common differential diagnoses of dactylitis in children include tuberculosis, sickle cell anemia, and psoriatic arthritis.