Researchers reported the rare case of a man with systemic mastocytosis (SM) with an associated hematological neoplasm (SM-AHN) who had 2 clonal hematological malignancies.

The case report, published in Acta Clinica Belgica, noted that the malignancies derived from different lineages: a B-cell chronic lymphatic leukemia (B-CLL) and a monocytic acute myeloid leukemia (AML) with myelodysplasia-related changes presenting as a myeloid sarcoma.

“The association of SM with myeloid sarcoma is rare with only two reported cases in literature,” the authors wrote. “This report highlights the importance of thorough hematological malignancy screening in patients diagnosed with SM, as well as the use of molecular and cytogenetic analyses to unravel underlying clonal pathogenesis and to guide risk classification and choice of therapy.”

The patient was a 69-year-old man diagnosed with B-CLL 8 years earlier with, at the time of diagnosis, a normal karyotype on cytogenetic analysis. A new cytogenetic analysis revealed an abnormal karyotype (trisomy 8 and del[13][q12.3q14.3]), as well as mutations in KIT D816V, DNMT3A, and RUNX1. This molecular profile is associated with an aggressive disease course and poor outcomes.

Further testing revealed SM and monocytic AML, in addition to residual B-CLL cells. A diagnosis of SM-AHN with 2 associated hematological malignancies was made.

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Treatment with cytarabine and idarubicin was initiated in combination with SM-directed midostaurin, but it had little effectiveness. Severe infectious complications led to a stay in the intensive care unit, and 5 months after the diagnosis of the second associated malignancy, the patient died.

The authors note the increasing importance of cytogenetic and molecular analyses in patients with SM-AHN due to the genetic heterogeneity of the disease and the potential of a normal karyotype changing to an abnormal karyotype over time, as occurred in this case. This genetic profiling can help determine the clonal origin and aid decision-making in terms of prognosis and therapeutic approach.


Decruyenaere P, Mazure D, Moors I, et al. Systemic mastocytosis with myeloid sarcoma and B-CLL: molecular and clonal heterogeneity in a rare case of SM-AHN with review of literature. Acta Clin Belg. 2023;78(1):58-66. doi:10.1080/17843286.2022.2033919