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The pseudo-Pelger-Huët anomaly in pyoderma gangrenosum associated with myelodysplastic syndrome
Melissa Chiang1, Matthew Fleming
1Department of Dermatology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA. mpchiang@mcw.edu
Abstract:
We report a case of pyoderma gangrenosum in which most of the neutrophils exhibited the pseudo-Pelger-Huët (pPH) anomaly, a cytologic abnormality affecting the neutrophil nucleus. Pelgeroid cells have round, oval, or hyposegmented nuclei and are therefore difficult to recognize as neutrophils. The pPH anomaly is important because it is found mostly in patients with myelodysplastic syndromes or myeloid leukemias. These patients are also at risk for developing neutrophilic dermatosis as well as leukemia cutis, the main differential diagnosis. In our case, the proper diagnosis was made with the help of immunohistochemistry.
Insights
Pyoderma gangrenosum can present with pseudo-Pelger-Huët anomaly in neutrophils, mimicking myeloid leukemia. Immunohistochemistry is crucial for accurate diagnosis in these challenging cases.
Area of Science:
- Hematology
- Dermatology
- Cytopathology
Background:
- Pyoderma gangrenosum is an inflammatory neutrophilic dermatosis.
- Pseudo-Pelger-Huët (pPH) anomaly is a nuclear abnormality in neutrophils.
- pPH anomaly is often associated with myelodysplastic syndromes and myeloid leukemias.
Observation:
- A case of pyoderma gangrenosum is presented.
- Most neutrophils in the affected patient exhibited the pPH anomaly.
- Pelgeroid cells have hyposegmented nuclei, complicating neutrophil identification.
Findings:
- The pPH anomaly in neutrophils can be mistaken for leukemia cutis.
- Accurate differentiation is critical due to shared risk factors in patients.
- Immunohistochemistry proved essential for correct diagnosis in this case.
Implications:
- Highlights the importance of recognizing pPH anomaly in dermatologic conditions.
- Emphasizes the role of advanced cytologic techniques in differential diagnosis.
- Underscores the need for careful evaluation in patients with hematologic malignancies and skin lesions.
