CD56+ Lymphoproliferative Disorders of the Skin—A Clinicopathologic Analysis of 34 Cases: A Multicenter Study From EORTC Cutaneous Lymphoma Project
Preliminary reports suggest that tumor cell expression of CD56 is associated with adverse clinical outcome in cutaneous lymphomas. However, prognostic subsets within the CD56+ group have been difficult to identify because of the lack of uniform clinicopathologic and limited clinical information. To define these entities better and to help confront such issues, 34 cases of CD56+ lymphoproliferations initially presenting in the skin were examined and reviewed by an expert panel. The clinical and histopathologic parameters were analyzed with respect to clinical course and prognosis. On the basis of the clinicopathologic characteristics, we could identify 4 different subtypes of lymphoproliferations with CD56 expression: (1) the so-called blastic CD56+ lymphomas, (2) aleukemic leukemia cutis of CD56+ myeloid leukemias, (3) extranodal NK/T-cell lymphoma, nasal type and, (4) “classical” cases of cutaneous T-cell lymphoma with coexpression of the CD56 molecule. Our findings indicate that CD56+ cutaneous lymphoproliferative disorders comprise a spectrum of different entities. Most of these entities are associated with an aggressive clinical course and poor outcome. However, CD56 expression for itself is not a prognostic marker as “classical CTCL” cases can also show coexpression of this molecule, which does not affect the relatively mild clinical course.