Prognostic Value of Histopathological Grading in Canine Extramedullary Plasmacytomas

Abstract

Abstract. The canine extramedullary plasmacytoma (cEMP) has recently been the subject of numerous investigations, indicating that the histomorphologic diagnosis is often difficult because of the variety of morphologic features. Therefore, the objective of this study was to establish a subclassification scheme for cEMPs and to evaluate correlations between the types and malignancy. Retrospectively, 117 cEMPs, all immunohistochemically characterized by a monoclonal immunoglobulin light-chain expression, were collected and assigned to morphologic types. These types were compared using data from a follow-up study on metastasis and tumor recurrence, then compared by proliferation rate, determined by immunohistochemical detection of the antigen Ki-67. Histopathologic typing revealed five different types of cEMPs, ranging from the mature type with typical plasma cells to the polymorphous-blastic type. Between these two forms, three additional types were established: hyaline, cleaved, and asynchronous. Most of the cEMPs were of the cleaved and asynchronous types. In all cEMPs, mononuclear and multinuclear giant cells were present to varying degrees. Although the results of cell proliferation and the follow-up study indicated less benign behavior by the polymorphous-blastic type, the proliferation rate revealed no statistically significant differences among the cEMP types. The clinical data therefore confirmed previous findings that the risk of tumor recurrence and metastasis in general can be classed as low. The established cEMP typing system is probably a very helpful diagnostic tool, although the types cannot be used for a tumor grading system.

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). The vast majority of the evaluated canine EMPs occurred in mongrels.…”

“…The present study described all six types of EMP in dogs, and among them monomorphous blastic type was the most frequent. According to the previous studies, the monomorphous blastic and cleaved type are the most common types of EMPs in dogs (Platz et al 1999, Cangul et al 2002.…”

“…The previous studies revealed that the feline EMPs are mostly benign. However, the possibility of metastases and recurrence cannot be excluded (Platz et al 1999, Gupta et al 2014). In contrast to multiple myeloma, there is no bone and bone marrow involvement in animals (Gupta et al 2014).…”

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.…”

Histomorphological and immunohistochemical characterization of 172 cutaneous round cell tumours in dogs

“…Cutaneous PCTs are uncommon and are usually benign (Jacobs et al 2002). Immunohistochemical markers such as CD79a (Schrenzel et al 1998) and immunoglobulins (Platz et al 1999) have been used as ancillaries in the diagnosis of this neoplasm. Variable immunohistochemical expression of the CD79a antigen has been found in PCTs, and positive staining CD79a was present in 56.2% to 80% of cases studied (Schrenzel et al 1998, Ramos-Vara et al 1998, Ramos--Vara et al 2007).…”