Large CD30‐positive cells in benign, atypical lymphoid infiltrates of the skin

Abstract

Background: Cutaneous infectious and inflammatory diseases may contain a significant number of CD30‐positive cells, thus mimicking lymphomatoid papulosis (LyP) or anaplastic large cell lymphoma. Methods: We reviewed our cases of non‐neoplastic skin conditions with large, CD30‐positive cells and searched the literature for similar cases. Results: A total of 28 cases were included in the study: Milker’s nodule (n = 8), Herpes simplex virus infection (n = 7), lymphomatoid drug reaction (n = 3), molluscum contagiosum (n = 3), nodular scabies (n = 2), leishmaniasis (n = 1), syphilis (n = 1), pernio (n = 1), ruptured infundibular cyst (n = 1) and pseudolymphoma in a scar (n = 1). CD30‐positive cells were often arranged in clusters and revealed both Golgi and membrane positivity, similar to what was observed in LyP and CD30+ anaplastic large T‐cell lymphoma. Conclusions: Analysis of our data and of those published in the literature shows that viruses and drugs are the most common cause for occurrence of large CD30‐positive cells in cutaneous pseudolymphomatous infiltrates. Arrangement of these large, CD30‐positive cells in small clusters is not unique to cutaneous CD30‐positive lymphomas, and in many cases a precise diagnosis can be made only upon accurate clinicopathological correlation or using ancillary methods such as polymerase chain reaction analysis for viral DNA.