Phagocytic plasmacytoma in a dog

Abstract

A 4-year-old neutered male Golden Retriever was presented to the oncology service of the North Carolina State University Veterinary Teaching Hospital for staging of a histiocytic sarcoma of the left forelimb, diagnosed on the basis of biopsies submitted by the referring veterinarian. Cytologic assessment of aspirates of 2 splenic nodules identified on ultrasonographic examination of the abdomen revealed a highly phagocytic population of neoplastic round cells morphologically suggestive of plasma cells. Histologic assessment of the forelimb mass after amputation of the limb revealed a neoplastic round cell population demonstrating extensive cytophagia and erythrophagia. Immunohistochemical analysis of the tumor population revealed it to be negative for BLA.36 with sporadic positivity for lysozyme and CD79a. Immunofluorescent evaluation revealed weak tumor cell positivity for immunoglobulin (Ig) A and IgM, but extensive strong positivity for IgG, confirming the plasma cell origin of the tumor. Although extensive phagocytic activity may strongly suggest histiocytic origin, plasma cell origin must also be considered among the differential diagnoses for phagocytic round cell tumors.

What is your diagnosis? Cutaneous ulcerated nodule in a geriatric dog

“…As previously described for CP, a consistent MUM‐1/IRF‐4 expression and a uniform immunolabelling of MHC‐class II antigen by neoplastic cells was noted, associated with occasional lysozyme+ cells …”

“…3,4 As previously described for CP, a consistent MUM-1/ IRF-4 expression and a uniform immunolabelling of MHCclass II antigen by neoplastic cells was noted, associated with occasional lysozyme+ cells. 1,5,6 In conclusion, this is the first report describing a canine CP with both intra-and extracellular amyloid deposition demonstrated in previously stained cytologic smears by Congo red stain and polarized microscopy.…”

Erythrophagocytic low‐grade extranodal T‐cell lymphoma in a cat

“…In animals, a variety of round cell neoplasms have been associated with erythrophagocytosis. In dogs, these include plasma cell disease, 14,15 megakaryoblastic leukemia, 16 and the CD11d1hematophagocytic variant of histiocytic sarcoma. 17 In cats, the only reported round cell neoplasia exhibiting erythrophagocytosis, to our knowledge, is mast cell disease.…”

Cytologic identification of erythrophagocytic neoplasms in dogs

“…In a description of 29 angiosarcomas in people, erythrophagia was a prominent feature, and 33% of classical types and 80% of epithelioid variants exhibited erythrophagia . This type of analysis has not been performed in veterinary medicine, although erythrophagia has been reported to occur in individual cases of mast cell and plasma cell tumors, lymphoma, megakaryocytic leukemia, and hemophagocytic histiocytic sarcoma . We predicted that erythrophagocytosis is a cytologic feature that could aid in classification of tumor type in veterinary patients.…”