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Abstract
The relationship between lymphomas such as mycosis fungoides and Langerhans cell histiocytosis (LCH) is exceedingly rare. Cases reported in the literature describe lymphomas preceding a diagnosis of LCH, as well as LCH followed by a diagnosis of lymphoma.
Here, we present the case of a 76-year-old man with a history of multiple years of recalcitrant, patch and plaque stage folliculotropic mycosis fungoides (FMF), without systemic involvement or Sezary syndrome, who developed malaise and painful, itchy, and bleeding nodules at multiple sites. Biopsy of one of the nodules revealed a very dense, nodular, dermal-based atypical lymphohistiocytic infiltrate (Figure 1A) composed predominantly of enlarged, atypical mononuclear histiocytoid-appearing cells with oval to kidney-bean shaped nuclei and moderate amounts of pale to clear-staining cytoplasm, consistent with atypical Langerhans cells. Several large intrafollicular Langerhans cell collections were also seen, findings suspicious for LCH. Additionally, there were scattered moderately enlarged, atypical-appearing lymphocytes in the epidermis and hair follicles, with follicular mucinosis noted, findings consistent with involvement by the patient’s known FMF with associated follicular mucinosis. Immunohistochemical staining showed that the atypical histiocytic cells were negative for CD3, but strongly, diffusely positive for S100, Langerin, and CD1a, as well as CD4, confirming concomitant LCH.
Treatment with a CD30 antibody, Brentuximab, was initiated. The patient has had notable improvement in lesion appearance with no signs of disease worsening. In our review of the literature, this appears to be the first reported case of LCH in a patient with a history of FMF.