Primary cutaneous CD30⁺lymphoproliferative disease (pcCD30⁺ LPD). (A) Diffuse dermal infiltrate of large atypical cells admixed with small lymphocytes. (H&E staining; original magnification, × 300). (B) The large atypical cells are strongly positive for CD30. (C-D) The histologic picture in panels A and B can be found both in C-ALC and in LyP. The final diagnosis depends on the clinical presentation. In combination with the solitary tumor of the patient shown in panel C the definite diagnosis will be C-ALC; in combination with recurrent, self-healing papulonecrotic skin lesions (D), the final diagnosis is LyP. Image acquisition for panels A and B was performed as described for Figure 1B. An HC Plan APO 20×/0.70 objective was used.