The most important aspect of diagnosing a histiocytic disorder is ensuring we have the full scope of patient data, including clinical, pathologic and radiographic information.

Having clinical data and radiographic images alongside pathology can ensure we’re making a complete and accurate diagnosis. Because both reactive inflammatory lesions and other tumors can draw many reactive histiocytes, simply putting histiocytic stains on a lesion can lead to misdiagnosis of a histiocytic disorder.

It’s also crucial to know that not any one stain is going to diagnose a histiocytic lesion. This means we need enough biopsy material to conduct a full immunophenotype panel, which includes multiple stains. We like to use the acronym “MIP” when diagnosing these conditions — meaning that we have the correct Morphology, Immunophenotype and Pattern of involvement, combined with the clinical and radiographic findings to make a comprehensive diagnosis.

Diagnostic Process

A diagnosis starts with studying the overall pattern and morphology of the cells in the hematoxylin and eosin (H&E) stain. Then, a targeted but broad immunophenotypic panel is used to help narrow the biopsy down to a specific histiocytic category.

Once we determine the type of lesional histiocytosis, we then move to molecular immunophenotyping, including BRAF staining, to help determine if there is a molecular alteration causing the disease. We also compare the molecular immunophenotype stains with DNA / RNA molecular-based testing to avoid false positives or false negatives.

Determining Systemic Involvement

Imaging tests, including CT scans and PET scans, will be used to see whether the histiocytic disorder is present in other organs or bones. Blood tests, including a complete blood count (CBC) and liver panel, may also be used to determine liver or bone marrow involvement.

Pathology and Testing for Histiocytic Disorders

If you need a consultation for a pathology case, you can download and fill out our pathology request form. Send the pathology request along with relevant clinical, radiologic and pathologic patient information, including:

  • Patient’s clinical information
  • Radiographic images (on a CD)
  • Existing pathology reports and original pathology slides
  • Tissue block or at least 10 unstained sections from the tissue block

You can send the intake form and related materials to:

Division of Pathology, MLC 1035
Cincinnati Children’s Hospital Medical Center
3333 Burnet Ave.
Cincinnati, OH 45229

If you have any questions, call us at 513-636-4261 or email