S100-negative CD1a-positive cutaneous histiocytosis is an exceedingly rare histiocytosis that is defined histopathologically by a dense dermal infiltrate of ovoid mononuclear cells with grooved nuclei and ample cytoplasm with variable nuclear atypia and mitoses that are immunohistochemically positive for CD1a and negative for S100 and CD207 (langerin). The histogenesis of S100-negative CD1a-positive histiocytosis is unclear, and its precursor cell has yet to be characterized. Although all cases thus far have been described as benign and occasionally self-resolving, the clinical course and outcome of this disease are not fully understood. This case expands the spectrum of disease associated with S100-negative CD1apositive histiocytosis given its malignant course.
We describe a patient with progressive scleromyxedema who failed to respond to previously described treatment modalities. A trial of plasmapheresis was initiated, but after an initial promising response, his disease continued to progress. The skin involvement appeared to progress even more rapidly after the plasmapheresis was discontinued.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.