Key points
- Affected tissue biopsy may help explain the cause of symptoms in patients with monkeypox who are severely immunocompromised.
- CDC's Infectious Diseases Pathology Branch (IDPB) is available to assist with testing formalin-fixed, paraffin-embedded (FFPE) biopsy tissue specimens for orthopoxviruses including monkeypox virus.
- IDPB must pre-approve specimen shipment.
Overview
Patients who are severely immunocompromised are at risk for more severe and complex monkeypox presentations. Determining which signs and symptoms may be due to monkeypox and which may be associated with other infections can be difficult. Some cases show infection with multiple pathogens in the same lesion. In those cases, clinicians may choose to perform a biopsy of the affected tissue to better understand the cause of specific symptoms and ensure appropriate patient management and care.
When a biopsy is performed, CDC's Infectious Diseases Pathology Branch (IDPB) is available to assist with testing of formalin-fixed, paraffin-embedded (FFPE) biopsy tissue specimens for monkeypox virus and other infectious etiologies, as indicated:
- With new or atypical lesions where it is unclear if the lesions are primarily due to monkeypox or another infectious cause, or secondary bacterial or fungal infections, or a combination of pathogens
- With significant complications including but not limited to mucosal lesions, bowel lesions, severe lymphadenopathy, pulmonary nodular lesions, or severe conjunctivitis.
Consult with your state health department before contacting CDC. CDC's IDPB must pre-approve specimen shipment.
Submitting biopsy tissues
Formalin-fixed, paraffin embedded (FFPE) biopsy tissue can be submitted to IDPB for additional pathologic characterization and infectious disease testing including for monkeypox virus.
Before submitting specimens to CDC
- Consult with your state health department before contacting CDC.
- Perform routine histopathologic evaluation of biopsy specimens at your clinical institution's pathology laboratory.
- Perform routine immunohistochemical and special stains for other infectious etiologies (e.g., fungal and bacterial organisms, herpes simplex viruses 1 and 2, cytomegalovirus, varicella zoster virus, adenoviruses) when indicated by your clinical institution's pathology laboratory.
Specific specimen acceptance considerations
Tissues should demonstrate histopathologic findings consistent with an infectious process. In addition:
- FFPE tissue blocks that have been submerged in formalin for ≤2 weeks prior to embedding in paraffin are acceptable
- Unstained slides for orthopoxvirus immunohistochemical (IHC) testing are acceptable, but evaluating other infectious etiologies may be limited
- Slides must be cut <10 days prior to submitting them
- Slides must be cut <10 days prior to submitting them
- Small specimens are acceptable
- To maintain specimen integrity, submit existing FFPE tissue blocks as-is and unsplit, which might further reduce available tissue in the block
- FFPE tissue blocks that have been depleted due to removal of tissue from the block as a result of prior testing are not acceptable for testing and will be rejected.
Shipping instructions
If approved, please follow these instructions:
- Send FFPE tissue specimens at ambient temperature or on cold packs during summer months to prevent the paraffin from melting.
- DO NOT send FFPE tissue specimens on dry ice as it can damage the specimens.
- For more information on how to send specimens, see Pathologic Evaluation of Fixed Tissues for Possible Infectious Etiologies (CDC-10365).