Hairy-cell leukemia presenting as lytic bone lesions.


Case Report A 56-year-old man with chronic low back and intermittent hip pain presented to our center with worsening symptoms. He reported no constitutional symptoms. Physical examination revealed tenderness on percussion of the lower dorsal and lumbar spine. His CBC included hemoglobin, 143 g/L; WBC, 6.5 10/L with a normal differential; and platelets, 112 10/L. Serum lactate dehydrogenase, calcium, PO4, albumin, uric acid, 2-microglobulin, and paraprotein levels were normal. Plain radiographs of the dorsal/lumbar spine, pelvis, and femora were unremarkable except for mild wedge compression of the D9 vertebral body. A magnetic resonance imaging (MRI) scan of the spine showed abnormal signal intensity in the vertebral bodies and posterior elements of vertebrae D3 through D6, D7, and D9 through L1, with an altered intramedullary signal in vertebrae L1, L2, L5, S2, and S3. An MRI scan of the pelvis showed increased T2 signal intensity that was widely distributed throughout the pelvis and sacrum, including both iliac crests, the posterior left ilium, both supra-acetabular areas, and within the femoral head and neck bilaterally. The marrow T1 signal was decreased. A computed tomography scan showed lytic areas within the vertebral bodies of D7 and D9 and a small lytic lesion within the right ilium that suggested metastases. Bone scintigraphy showed some uptake at D9 but no other changes to correlate with the computed tomography scan findings. Abdominal ultrasound revealed hepatic steatosis but no splenomegaly. A blood film and bone marrow aspirate with flow cytometric immunophenotyping were interpreted as essentially normal. Retrospective review confirmed the absence of hairy cells on the blood film, with only rare cells suggestive of hairy cell leukemia (HCL) in the bone marrow aspirate and touch imprints. The hematoxylin and eosin slides of the bone marrow biopsy appeared free of disease (Fig 1A), but subsequent CD20 immunohistochemistry revealed a sparse interstitial infiltrate that was suggestive of HCL (Fig 1B). Hematoxylin and eosin staining of an open biopsy of the left iliac crest revealed a diffuse infiltrate of lymphocytes with cleaved nuclei and abundant cytoplasm (Fig 1C), and immunohistochemistry was positive for CD20, CD10, BCL2, and cyclin D1, and negative for CD3, CD5, and CD138. Flow cytometry revealed coexpression of CD19, CD20, CD10, CD11c, CD25, and CD103, which established a diagnosis of hairy cell leukemia. Enzyme cytochemistry confirmed tartrateresistant acid phosphatase positivity, special stains confirmed reticulin fibrosis, and polymerase chain reaction confirmed a clonal immunoglobulin heavy chain gene rearrangement. Fluorescent in situ hybridization was negative for translocations t(11;14) and t(14;18). Bone biopsy was referred in consultation to P. Kurtin at the Mayo Clinic, who confirmed the diagnosis of HCL and kindly performed and reported annexin A1 immunocytochemistry, which was positive and consistent with HCL. Analysis of the BRAF gene by shifted termination assay and capillary electrophoresis (Applied Biosystems BRAF Mutation A

DOI: 10.1200/JCO.2012.47.5301

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@article{Gray2013HairycellLP, title={Hairy-cell leukemia presenting as lytic bone lesions.}, author={Madison Tanner Gray and Michael Nevin Rutherford and Denis Maurice Bonin and Bruce Patterson and Pedro Guarionex Lopez}, journal={Journal of clinical oncology : official journal of the American Society of Clinical Oncology}, year={2013}, volume={31 25}, pages={e410-2} }