Chromosome abnormalities in malignant histiocytosis

Area of Science:

• Cytogenetics
• Oncology
• Hematology

Background:

• Malignant histiocytosis (MH) is a rare neoplastic proliferation of cells of the monocyte-macrophage lineage.
• Understanding the genetic underpinnings of MH is crucial for diagnosis and treatment.

Observation:

• Two patients, a 12-year-old boy and a 62-year-old woman, diagnosed with malignant histiocytosis underwent chromosome and pathologic studies.
• Both patients exhibited distinct chromosome abnormalities in their neoplastic cells.
• The boy's karyotype was 45,Xp+,-Y,9p+,18q-, and the woman's was 48,XX,+16, inv(1),mar(5),6p-,10p+,12q+,i(18q),+i(18q).

Findings:

• The boy presented with typical MH features and did not achieve remission with chemotherapy.
• The woman initially showed MH characteristics but did not respond to chemotherapy.
• At later stages, the woman's condition evolved, with bone marrow and autopsy findings consistent with non-Hodgkin lymphoma, diffuse large cell type, though some histiocytic cells persisted.
• A review of six additional cases alongside the current study failed to identify any specific chromosome changes characteristic of malignant histiocytosis.

Implications:

• The findings suggest that malignant histiocytosis may not have a specific cytogenetic signature.
• The potential for MH to transform into or be associated with non-Hodgkin lymphoma warrants further investigation.
• Further research is needed to elucidate the genetic landscape and pathogenesis of malignant histiocytosis.