[508] CD163: A Highly Specific Marker for Myeloid Leukemia Cutis

PW Harms, L Ma. University of Michigan Health Systems, Ann Arbor, MI

Background: Recognition of myeloid leukemia cutis (LC) is clinically important. However, currently used immunohistochemical markers can be insufficiently sensitive and/or specific for definitive diagnosis. CD163, a haptoglobin-hemoglobin scavenger receptor, has been shown to be largely restricted to the monocyte/histiocyte lineage. We investigated the utility of CD163 in the diagnosis of myeloid LC with a monocytic component.
Design: A total of 34 cases, including 18 cases of myelomonocytic or monocytic LC (acute myeloid leukemia, M4 or M5), 10 cases of myeloid LC without monocytic component, and 6 cases of T- or B-cell acute lymphoblastic leukemia/lymphoma, were stained for CD163.
Results: We observed CD163 expression in 8 of 18 (44%) of myelomonocytic or monocytic LC and 1 of 10 (10%) of other myeloid LC. CD163 was not expressed in any of the acute lymphoblastic leukemia/lymphoma cases (0/6). Results are summarized in Table 1.

Table 1. CD163 expression by immunohistochemistry in leukemia cutis.
AML-M44/11 (36%)
AML-M53/6 (50%)
AML-M4-58/18 (44%)
AML, other than M4-51/10 (10%)
AML, all9/28 (32%)
ALL0/6 (0%)
Numbers of positive cases are given as a fraction over total cases stained. Abbreviations: AML, acute myeloid leukemia; ALL, acute lymphoblastic leukemia/lymphoma.

Conclusions: These results suggest that, in combination with currently used immunohistochemical markers, CD163 is valuable as a specific marker for myeloid LC with monocytic differentiation.
Category: Dermatopathology

Wednesday, March 24, 2010 1:00 PM

Poster Session VI # 100, Wednesday Afternoon


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