Mast cell leukemia (MCL) is a rare and aggressive type of systemic mastocytosis (SM), a disorder characterized by an abnormal buildup of mast cells in various organs. It is usually diagnosed after a patient develops osteoporosis and a weakened area of bone suffers a fracture. But as outlined in a case report recently published in the Journal of Hematology, patients with MCL may present with different symptoms that complicate diagnosis.
In this case, instead of bone weakening a 75-year-old woman developed widespread osteoblastic lesions, or areas of thicker bone. Additionally, these areas were found in her ribs, spine, pelvis, and thoracic region, an unusual presentation for MCL that added complexity to her diagnosis.
“By this case we would like to report that MCL is a malignancy that can present with both osteolytic and osteoblastic bone lesions and stress the importance of bone biopsy in suspected cases of MCL,” the authors noted.
The patient had initially sought emergency care for nausea, vomiting, and weakness. Imaging revealing osteoblastic lesions in her ribs and pelvic bones and enlargement of the liver and spleen. A bone marrow biopsy showed an overabundance of abnormal mast cells and elevated levels of serum tryptase, and the patient was diagnosed with MCL.
A key challenge in diagnosing MCL lies in its variability. The disease can be classified as either primary, occurring spontaneously, or secondary, arising from a preexisting mast cell disorder. In addition, it may present in acute or chronic forms. Acute MCL, as seen in this case, involves aggressive disease progression and significant organ damage, while chronic MCL develops more slowly and has a relatively better prognosis. Aleukemic MCL, another rare subtype, features fewer mast cells in the bloodstream, making early detection even more difficult.
Treatment options for MCL include targeted therapies such as avapritinib and midostaurin, which have been approved by the United States Food and Drug Administration for advanced SM. However, due to the disease’s aggressive nature, many patients experience rapid decline before treatment can take full effect.
“MCL carries a very poor prognosis, particularly acute MCL, which has a median OS [overall survival] of 2 to 3 months despite treatment,” the authors noted.
Read more about SM prognosis
In this case, the patient’s worsening condition led to discussions about clinical trials and specialized care, but she ultimately transitioned to hospice and passed away within three weeks of her initial hospitalization.
The unusual presence of osteoblastic lesions in MCL highlights the need for increased awareness and improved diagnostic strategies for this rare leukemia. Because the symptoms can mimic other conditions, early identification is essential to providing timely and appropriate interventions. Advancements in genetic testing and targeted therapies may offer hope for better outcomes, but for now, MCL remains a formidable challenge in hematology and oncology.
Despite recent medical advancements, MCL continues to be one of the most lethal forms of systemic mastocytosis. Understanding its diverse presentations, including rare bone abnormalities, can help physicians recognize the disease earlier, potentially improving treatment options and patient survival.
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