Case Report and Review Highlight Importance of Identifying Osteolytic Lesions in MPNs

Myeloproliferative neoplasms (MPNs) are rare, but they can have debilitating symptoms and negatively impact patients’ lives. Even more rare is the development of osteolytic lesions in patients with MPNs. A recent case study was the first to report an osteolytic lesion in a patient with chronic polycythemia vera (PV).

MPNs are rare clonal disorders affecting hematopoietic progenitor cells, with the 3 most common being PV, essential thrombocytosis (ET), and myelofibrosis (MF). Morbidity associated with disease-related symptoms, thrombotic events, and the potential for MPNs to transform into acute myeloid leukemia (AML) are all concerns with MPNs, as are negative quality-of-life impacts.

Bone pain is a relatively common symptom in MPN patients, with 44% reporting it and up to a third of patients overall experiencing “very severe” bone pain, according to the study authors. Previous surveys at the Princess Margaret Cancer Centre, Canada’s largest MPN program and the location of the case study, have gathered data from 1096 patients with MPN to characterize symptoms. Of those patients, 208 reported bone pain, 17% of whom have PV, 15% who have ET, and 50% with MF.

In the case report, a 59-year-old woman was diagnosed with PV following molecular testing and bone marrow biopsy in 2019. She started a regimen of 81 mg of aspirin daily, plus phlebotomies as necessary. The patient presented with excruciating hip pain and visited the emergency department multiple times in 2020, when MRI and CT scans of her right hip showed a lytic lesion in the right femur.

Fluorodeoxyglucose positron emission tomography (PET) scan also confirmed the lesion and showed increased metabolic activity, and a CT-guided biopsy of the area showed hematopoietic tissue with hypercellularity and panmyelosis, which is consistent with PV. The patient was prescribed 5 mg of ruxolitinib twice daily to mitigate pain based on previous case reports, and 6 months later the hip pain improved significantly. MRI also showed improvements.

Study authors conduced a literature review, searching for patients diagnosed with PV, ET, primary myelofibrosis, and unclassified MPN associated with osteolytic bone lesion from 1970 to July 2021. In general, osteolytic lesion secondary to MPNs is rare regardless of the subtype of MPN, and just 16 case reports were found.

All patients with osteolytic lesions had bone pain, and 15 of 16 had MF, while 1 patient had PV and presented with the lesion as they progressed to AML. Patients typically underwent multiple hospital admissions and interventions after osteolytic lesions were found.

Fourteen patients only experienced temporary symptomatic relief with treatment, and treatments varied, including palliative radiation, orthopedic surgery for pathological fracture, steroid therapy, Janus kinase inhibitors, and chemotherapy. In 2 patients, radiographic resolution was achieved—in 1 case following allogeneic stem cell transplant and the other following a regimen of ruxolitinib for symptomatic splenomegaly, similar to the case study. Disease progressed in all cases that involved osteolytic lesions. In 9 cases, disease progression or death occurred within one year of osteolytic lesion presentation.

Overall, it is very rare that osteolytic lesions occur in MPN patients without any other concurrent malignant process, although the etiology of these lesions is not entirely understood. From a clinical standpoint, the findings of the review suggest that osteolytic lesions could be a sign of worse prognosis and disease progression in addition to other known indicators of high-risk cases.

“The presence of persistent worsening bone pain in patients with MPN should prompt imaging with CT scan followed by PET scan as needed to investigate for lytic lesions, especially with the poor prognosis associated with this finding,” the authors wrote. When lesions are found, ruling out concurrent hematological malignancies and repeating biopsy to evaluate disease progression is the next recommended approach.

This was the first reported case of osteolytic lesion in chronic-phase PV, but the presence of osteolytic lesions in MPNs overall could be an indicator of worsening disease. Therefore, the main symptom of osteolytic lesions, progressively worse bone pain, should not be taken lightly.

Reference

Cheung V, England J, Maze D, Sibai H. Osteolytic lesion in polycythemia vera: First report and review of literature. eJHaem. Published online March 27, 2022. doi:10.1002/jha2.420