Plasmacytoma TUMOR TIDBITS, A BIWEEKLY EMAIL NEWSLETTER FROM GULF COAST VETERINARY ONCOLOGY Number 85; January 24, 2003. ======================================================================= THIS WEEK'S TUMOR TIDBIT: Plasmacytoma. ======================================================================= THIS WEEK'S ANNOUNCEMENTS We're celebrating again! Please watch for announcements regarding our Second Annual Celebration of Life, to be held at our Houston clinic Saturday March 15th. Come bring a photograph of your pet and celebrate the joy of caring for our furry children. All are welcome. Don't forget, we've added a third day of clinical service in our San Antonio clinic beginning in March! Dr. King returns to San Antonio for consultations in Radiation Oncology. Please call our reception desk at the Broadway Clinic at 210-822-1913 to see Drs. Hahn, Carreras and King in SAn Antonio Tuesdays through Thursdays. Please call our Clinical Trials Assistant, Ms. Kelly Griffice, if you have questions about pet eligibility for our ongoing clinical trials. ======================================================================= This Tidbit discusses some of the interesting features of cutaneous and mucocutaneous plasmacytomas in dogs. These tumors are most commonly observed along the mouth, feet, trunk, anus and ears. In general, the onset and growth of a mucocutaneous plasmacytomas is rapid. The masses appear usually as a raised or ulcerated solid nodule about 0.25-6.0 cm in diameter; however plasmacytoma of the lips is typically small, solitary and rarely polyploid. In rare circumstances, it may represent a subtype of extrameduIlary plasmacytoma that is primary tumor of soft tissue origin or metastasis of primary osseous multiple myeloma. In a recent review, the Yorkshire terrier was the most commonly affected breed and males were affected more commonly than females. The mean and median age at diagnosis for dogs is 9.7 and 10.5 years, respectively. Systemic signs rare. Biopsy distinguishes them from other round cell tumors (e.g., lymphosarcoma, mast cell tumor, histiocytoma, and transmissible venereal tumor) and poorly differentiated, carcinoma, or amelanotic melanoma. Laboratory test results are usually normal unless the patient has multiple myeloma or lymphosarcoma. Cytologic examination of fine-needle aspirate reveals moderate to marked cellularity; individual tumor cells round to polyhedral with discrete margins and prominent anisocytosis and anisokaryosis; round to oval nuclei with fine to coarse chromatin and no visible nucleoli. Cytoplasm stains lightly basophilic. Histologically, most tumors are well circumscribed and easily identifiable Plasmacytomas are histologically classified into mature, hyaline, cleaved, asynchronous, monomorphous blastic and polymorphous blastic cell types. Monomorphous blastic cell type is the most frequent type, followed by cleaved and asynchronous cell types. Secondary amyloid depositions can be observed in some cases. No significant correlations are observed between the cell type and the location of the tumor, presence of amyloid or prognosis. Tumors are often invasive, so aggressive surgical excision is recommended. Radiotherapy is indicated for those tumors incompletely excised or in difficult locations (sublingual). Chemotherapy is often not recommended but can be used for palliation (steroid suppression with or without an alkylating agent such as Cytoxan, Luekeran, or Alkeran). The expected course and prognosis is regarded as excellent in most patients following complete excision or localized irradiation. SO WHAT DO WE DO AT GULF COAST? * First, we review the pathology report to determine if immunohistochemistry is indicated to rule out any other round cell neoplasm such as lymphoma, mast cell tumor, or amelanotic melanoma. * Second, when appropriate, we consider clinical staging that may include survey radiography, ultrasonography, and additional laboratory testing or bone marrow aspiration. * Third, when appropriate, we recommend therapy with intent for cure with considerations for surgical removal, irradiation or both. ======================================================================= As always, we hope this info helps and don't hesitate to call or email us Gulf Coast Veterinary Oncology! Kevin A. Hahn, DVM, Phd, Diplomate ACVIM (Oncology), drhahn@gcvs.com Janet K. Carreras, VMD, Diplomate ACVIM (Oncology), drcarreras@gcvs.com Glen K. King, DVM, MS, Diplomate ACVR (Radiology & Radiation Therapy), drking@gcvs.com Gulf Coast Veterinary Diagnostic Imaging & Oncology 1111 West Loop South, Suite 150, Houston, TX 77027 P: 713.693.1166 F: 713.693.1167 W: www.gcvs.com