Molecular characterization of IDCH and additional myeloid malignancies. (A) Oncoprint depicting clinicopathologic and molecular features of 12 patients with IDCH, 6 patients with potential IDCH, and 1 patient with MH-IDC (depicted on the far right). Every column represents 1 patient; case numbers are provided at the bottom of the plot. Blue squares indicate the presence of a clinicopathologic characteristic, orange squares indicate the presence of a gene fusion, red squares indicate the presence of a SNV or insertion and/or deletion (indel), and purple squares indicate the presence of CNV. (B) Genetic findings in 4 patients of whom 2 separate IDCH lesions were molecularly analyzed, demonstrating identical mutations in paired lesions in all cases. In addition, mutations unique to 1 lesion were sometimes identified. (C) Genetic findings in 4 patients of whom the additional myeloid malignancy was molecularly analyzed. Shared genetic alterations between the IDCH and additional hematologic malignancy were identified in 2 of 4 cases, strongly suggesting a clonal relationship of these hematopoietic neoplasms. Details on detected genetic alterations, including variant allele frequencies, are provided in supplemental Tables 3 and 4. CNV, copy number variation; MH-IDC, malignant histiocytosis with an indeterminate dendritic cell phenotype; SNV, single-nucleotide variant.