Dutcher bodies: cytoplasmic inclusions within the nucleus

Abstract

We read with great interest the recently published updated British Committee for Standards in Haematology (BCSH) guidelines on the diagnosis and management of Waldenstr€ om macroglobulinaemia (Owen et al, 2014). The authors are to be congratulated for producing an excellent, comprehensive and clear guideline. However, we differ with regard to the statement that ‘Dutcher bodies are intranuclear inclusions of immunoglobulin’. Dutcher bodies certainly appear to be intranuclear; however, they are intracytoplasmic immunoglobulin inclusions that invaginate into or overlie the nucleus. Sometimes the process of invagination can be clearly seen (Bain, 2009a). Dutcher bodies are thought to most probably result from the accumulation of immunoglobulin in the perinuclear cisterna (Brunning & Parkin, 1976). These inclusions have therefore been termed periodic acid-Schiff (PAS)-positive intranuclear ‘pseudoinclusions’ by the World Health Organization 2008 classification (Swerdlow et al, 2008). Indeed, Dutcher bodies were first described as intranuclear inclusions by Dutcher and Fahey (1959) in patients with Waldenstr€ om macroglobulinaemia. These PAS-positive inclusions were initially thought to have originated in the nucleus, only to be subsequently extruded into the cytoplasm via a ruptured nuclear membrane (Dutcher & Fahey, 1959). Russell bodies are also intracytoplasmic. They are typically spherical immunoglobulin inclusions that can expand to fill the cytoplasm of a cell with a single or multiple inclusions. Multiple Russell bodies can fill the cytoplasm and form a so-called Mott cell (Bain, 2009b). Russell bodies were initially described in the British Journal of Medicine in 1890 by the pathologist William Russell (1852–1940) who confidently described an ‘organism’ that caused cancer (Russell, 1890). Dutcher bodies, single or multiple Russell bodies and the inclusions of Mott cells are therefore morphological evidence of the same cytoplasmic inclusion(s) (Zini et al, 2010). Of course, we know now that both Dutcher bodies and Russell bodies are not specific to neoplastic plasma or plasmacytoid cells. Indeed they have been described in a number of reactive conditions (Gray & Schwartz, 2002) and other B-cell neoplasms (Metz et al, 1992). Although Mott cells, Dutcher bodies and Russell bodies are all aspects of the same phenomenon, the correct description of these inclusions helps to avoid confusion.