Atypical CD30+ cutaneous lymphoid proliferation in a patient with tuberculosis infection.

We describe the case of a 65-year-old woman affected by a diffuse lymphadenopathy consistent with tuberculous infection who developed a papular eruption on the head and neck region. Histopathologic examination of one papule showed an atypical CD30+ lymphoid infiltrate, which initially was cause of concern for the pathologists but was eventually regarded as reactive in nature. The case reported herein enlarges the spectrum of inflammatory infiltrates in which atypical CD30+ cells may be found. Since the reactive atypical CD30+ cells are morphologically similar to those cells observed in CD30+ lymphoproliferative disorders, including lymphomatoid papulosis, complete clinical history and laboratory findings are necessary to make the final and correct diagnosis. Although the pathogenetic relevance of the presence of CD30+ cells within the cutaneous infiltrate of patients with systemic tuberculosis remains to be determined, our findings support the hypothesis that the cytokine profile associated with tuberculosis may not be strictly TH1-like, and that a TH1-like to TH2-like switch may also occur.