Histopathologic and Immunophenotypic Characterization of Extramedullary Plasmacytomas in Nine Cats

Abstract

Abstract. To contribute to the existing body of knowledge in the literature on the apparently rare extramedullary plasmacytoma in cats, lymphoid tumors with plasmacytic cellular morphology taken from nine cats were examined. The paraffin-embedded material was investigated by standard hematoxylin and eosin, and special staining techniques (Giemsa, Congo-red, and periodic acid-Schiff reaction). The tumors also were examined immunohistochemically for the presence of immunoglobulin G, immunoglobulin A, immunoglobulin M, immunoglobulin light chains (, ), various amyloid proteins, and FeLV-antigen (p27 protein). An immunoglobulin-producing tumor of plasmacellular origin (extramedullary plasmacytoma [EMP]) could be diagnosed in all cases on the basis of immunohistochemical light-chain expression. All but one of the neoplasms occurred in the skin of older, predominantly male cats. As in humans and dogs, the following types could be identified according to their morphologic features: mature type (two), cleaved type (two), asynchronous type (four), and polymorphous type (one). The tumor tissue of three cats revealed amyloid deposits, which were immunohistochemically diagnosed as AL-amyloid in all three cases.

Morphology and immunoreactivity of canine and feline extramedullary plasmacytomas

“…The evaluated in our study EMPs were seen mostly in older animals, what corresponds to other reports (Platz et al 1999, Majzoub et al 2003, Rannou B et al 2009, Gupta et al 2014. Most of the tumours were located in the skin, what was also revealed by other authors (Platz et al 1999).…”

“…Cutaneous and oral cavity EMPs have more benign behavior than EMPs localized elsewhere (Borgatti 2010, Gupta et al 2014. In cats, European Short-Haired breed is predisposed to EMP (Majzoub et al 2003, Borgatti 2010. EMP in cats mostly arises in the gastrointestinal tract, especially rectal mucosa, sometimes tumour can be found in the esophagus, lungs, spleen, kidney, retroperitoneal space, orbit, and brain (Majzoub et al 2003, Borgatti 2010.…”

Cutaneous Lymphoplasmacytic Lymphoma with Systemic Metastasis in a Cat

“…Amyloid deposits in canine and feline EMP have been demonstrated by several authors [6,7,9]. Such deposits are considered to be one of the characteristic features of EMP.…”

“…The histological appearance of feline extramedullary plasmacytomas (EMP) has been previously reported [6]. The tumors were composed mostly of differentiated plasmacytic tumor cells with abundant cytoplasm and could be diagnosed on the basis of immunohistochemical -Ig light chains expression [6].…”

“…The tumors were composed mostly of differentiated plasmacytic tumor cells with abundant cytoplasm and could be diagnosed on the basis of immunohistochemical -Ig light chains expression [6]. Whereas LPL is an admixture of various differentiated lymphocytes, EMPs could be derived from a clonal plasma cell proliferation.…”