"Seminoma" TUMOR TIDBITS, A BIWEEKLY EMAIL NEWSLETTER FROM GULF COAST VETERINARY ONCOLOGY Number 80; December 6, 2002. ======================================================================= THIS WEEK'S TUMOR TIDBIT: Seminoma. ======================================================================= ANNOUNCEMENTS FROM GULF COAST VETERINARY ONCOLOGY * Ongoing clinical trials include those for dogs with relapse lymphoma and dogs with splenic hemangiosarcoma. Please call us for additional information and eligibility. * Visit our web site regular for updates and protocols, http://www.gcvs.com. ======================================================================= SEMINOMA Seminoma is usually a benign unilateral, solitary tumor of the testis. It is often difficult to palpate but is common in occurrence. One in nine dogs > 4 years old have a seminoma and 71% are not detected by physical examination. WHAT'S IN THE TEXTBOOKS? * It usually affects old male dogs. * Their mean age is 10 years. * There is no breed predisposition. * Clinical signs are rare. * Signs are rarely associated with feminization from estrogen excess. * Commonly associated with cryptorchidism. DIFFERENTIAL DIAGNOSES * Sertoli cell tumor. * Interstitial cell tumor. DIAGNOSTIC APPROACH & RESULTS * Laboratory results are usually normal unless the patient has evidence of male feminization syndrome. * Tumors < 3 cm diameter usually hypoechoic on ultrasound. * Tumors > 5 cm diameter usually have mixed echo pattern on ultrasound. TREATMENT CONSIDERATIONS * Castration and histopathologic examination is the treatment of choice. * Radiotherapy has been reported to be effective in patients with seminoma and metastasis to regional lymph nodes. EXPECTED COURSE AND PROGNOSIS * Usually excellent after castration. * This tumor usually has a benign behavior but some metastasize to regional Iymph nodes, visceral organs, lungs, and other sites. ASSOCIATED CONDITIONS & COMMENTS * Most tumors are < 2 cm diameter and affect one testicle; rarely bilateral. * Prostate disease, perianal adenoma, and perineal hernia may accompany seminoma. * One third of seminomas are found in a cryptorchid testis. * Extrascrotal seminomas more common in the right testis. WHAT DO WE DO AT GULF COAST VETERINARY ONCOLOGY? * When a pet has been diagnosed with metastatic seminoma (most commonly to the sublumbar or iliac nodes), radiation therapy should be considered and median symptom-free survival times exceeding 2 years are often observed. Systemic metastases are rare and have been observed (personal experience) in fewer than 5 pets in the past 15 years. ======================================================================= We hope this info helps and don't hesitate to call 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 =======================================================================