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Cytophagic and S-100 protein immunoreactive myeloid leukemia cutis
Crystal G Thomas1, Rajiv M Patel, Wilma F Bergfeld
1University of Texas Southwestern Medical Center, Department of Dermatology, Dallas, TX, USA.
Insights
Leukemia cutis (LC) can present unusually, even in patients without prior myeloid leukemia history. This case highlights S-100 protein positivity and cytophagocytosis as diagnostic clues for myeloid leukemia cutis.
Area of Science:
- Dermatology
- Hematology
- Oncology
Background:
- Myeloid leukemia cutis (LC) involves skin by neoplastic myeloid leukocytes.
- It can arise independently or alongside various myeloid disorders.
Observation:
- An 87-year-old woman presented with an unusual case of leukemia cutis.
- This patient had no prior history of myeloid leukemia or hematologic disorders.
Findings:
- The leukemia cutis exhibited cytophagocytosis, typically seen in lymphoid malignancies.
- Immunohistochemistry revealed S-100 protein positivity in the atypical myeloid infiltrate, an uncommon finding in LC.
- Cytophagocytosis and S-100 positivity can be diagnostic clues for myeloid LC.
Implications:
- These findings emphasize the importance of comprehensive evaluation for LC, even with atypical features.
- Cytophagocytosis in myeloid leukemia has prognostic significance.
- Recognizing unusual presentations aids in timely diagnosis and management of myeloid leukemia cutis.
Abstract:
Myeloid leukemia cutis (LC) is the cutaneous involvement by neoplastic leukocytes of the myeloid series. Myeloid LC may occur de novo or concurrently with acute myeloid leukemias, chronic myeloid leukemias, other myeloproliferative disorders or myelodysplastic syndromes. We describe an unusual case of cytophagic S-100 protein immunoreactive leukemia cutis presenting in an 87-year-old woman without prior history of myeloid leukemia or other hematologic disorders. We outline key histologic and immunohistochemical features that aide in the diagnosis of LC. The presence of cytophagocytosis on histologic examination, a phenomenon more commonly associated with lymphoid rather than myeloid malignancies, provided a clue to the possibility of a malignant process. The atypical myeloid infiltrate showed S-100 protein positivity, an unusual finding that may be seen in LC. Although not commonly reported in LC, the presence of S-100 protein positivity and cytophagocytosis should not lead to the premature exclusion of LC as a possible diagnosis until a thorough clinical, histologic and immunohistochemical evaluation is performed. In addition, the presence of cytophagocytosis has been shown to have prognostic significance for patients with myeloid leukemia.
