Pyogenic variant of primary cutaneous anaplastic large-cell lymphoma: a lymphoproliferative disorder with a predilection for the immunocompromized and the young.

Cutaneous anaplastic large-cell lymphoma belongs to the class of primary cutaneous CD30-positive lymphoproliferative disorders. The pyogenic variant is marked by a neutrophil rich inflammatory background. We describe 2 cases (one which clinically presented as cellulitis, and another arising in a patient with Hodgkin lymphoma) and review the clinicopathologic features of cases reported in the literature. In all cases, the male to female ratio is 1.2:1. The average age at presentation for patients with this variant is 47 years old with 15% of patients being 25 years old or younger. Thirteen percent of patients are immunocompromized. Ten percent of patients experience extracutaneous disease progression and 18% of patients are dead at 10 months. Immunophenotypically, the anaplastic large cells demonstrate loss of pan-T cell antigens, CD2, CD3, CD5, and CD7, with 65% of cases expressing CD4 and 29% of cases expressing CD8. Epithelial membrane antigen expression is reported in over half of the cases. In the clinical context of a progressive ulcerating lesion in younger or immunocompromized patients, it is important for the pathologist when presented with a skin specimen demonstrating a neutrophil-rich inflammatory background to include the pyogenic variant of anaplastic large-cell lymphoma. We hope to increase awareness of this rare CD30-positive lymphoproliferative disorder subtype by better defining the clinical spectrum in which this entity can present.