We report 50 cases of peculiar histiocytic proliferations occurring in diverse body sites that currently bear various names, including nodular mesothelial/histiocytic hyperplasia, nodular histiocytic aggregates, mesothelial/monocytic incidental cardiac excrescences, reactive eosinophilic pleuritis, histioeosinophilic granuloma of the thymus, and intralymphatic histiocytosis. They can sometimes cause considerable differential diagnostic difficulties by resembling a metastatic carcinoma or Langerhans cell histiocytosis. Several previous publications have established a link between some of these conditions, suggesting that these are merely variations within a histopathologic spectrum, affecting different organs and bearing different names based on a particular location. However, no publication has ever comprehensively addressed all of these lesions together in one study in an attempt to explain and discuss their striking analogy. Having studied a large series of cases we provide evidence that all these lesions share the same morphologic, immunohistochemical, and pathogenetic properties, thus they all represent the same pathologic process and should be referred to as such. Taking into account their typical nuclear features we propose a collective term “histiocytosis with raisinoid nuclei” for this spectrum of conditions.
*Department of Pathology, Charles University, Biomedical Center
†Department of Pathology, Charles University, Medical Faculty and Charles University Hospital Plzen, Plzen
‡Department of Pathology, First Faculty of Medicine and General University Hospital, Charles University in Prague, Prague
¶Department of Pathology, Regional Hospital Benesov, Benesov, Czech Republic
§Institute of Pathology, Friedrich-Alexander University Erlangen-Nürnberg, University Hospital, Erlangen
∥Dermatopathologische Gemeinschaftspraxis, Friedrichshafen, Germany
Conflicts of Interest and Source of Funding: Supported by the National Sustainability Program I (NPU I) Nr. LO1503 provided by the Ministry of Education Youth and Sports of the Czech Republic. The authors have disclosed that they have no significant relationships with, or financial interest in, any commercial companies pertaining to this article.
Correspondence: Michael Michal, MD, Department of Pathology, Charles University, Medical Faculty and Charles University Hospital Plzen, Alej Svobody 80, 304 60 Pilsen, Czech Republic (e-mail:email@example.com).