Unusual presentation of hairy cell leukemia as isolated bone lesions
Bibliographic record
Abstract
1335 Learning Objectives 1. Present the imaging findings of FDG PET/CT, bone scan, Gallium scan, MRI and CT of hairy cell leukemia (HCL) with isolated bone lesions 2. Review clinical presentation and treatment of HCL, a rare B-cell lymphoproliferative disorder 3. Describe and compare the pathological findings of HCL and B-cell lymphoma A 50 year old male presented with right hip pain. An MRI showed bilateral hip avascular necrosis. He subsequently had right hip decompression and bone graft, with the pathology showing increased lymphocytes of uncertain significance. Due to persistent right hip pain, a follow-up MRI was performed 2 years later which showed marrow replacing lesion in the right proximal femur that involved the epiphyses. A chest and abdominal CT identified anterior mediastinal, right paracardiac, retrocrural, and retroperitoneal lymphadenopathies. Core needle biopsies of the left paraspinal soft tissue mass were positive for lymphoid cell infiltration, with the morphological and immunophenotypic features in favor of nodal marginal zone lymphoma. However, the presence of positive cyclin D1 staining raised the possibility of a mantle cell lymphoma. Bone scan and Gallium scan were performed to rule out osteomyelitis. Susequently, bony lesions from the right femoral head and neck were biopsied and the final diagnosis is HCL. The original pathology from the paraspinal mass was reviewed and is consistent with HCL. The patient was later treated with a 5 day course of cladribine and on follow-up FDG PET/CT study was free of any disease in the right hip. HCL is a rare hematological malignancy representing 2% of all leukemias, with about 700 new cases diagnosed annually in the United States. We present a case of HCL in a male with persistent right hip pain, with unusual initial presentation of the bony lesions, followed 3 years later by soft tissue masses. In addition, the initial soft tissue biopsy was misdiagnosed as nodal marginal zone lymphoma. The distinction between hairy cell leukemia and marginal zone lymphoma is often difficult as they have many overlapping features.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.003 | 0.001 |
| Insufficient payload (model declined to judge) | 0.008 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".