Veterinary Medicine - September 2008 - (Page 496)

A challenging case PEER-REVIEWED dark and smooth-walled, and involved the right phrenic nerve. The cyst was excised en bloc and submitted for histologic examination. A 12-F chest tube was placed between the right eighth and ninth ribs. The sternotomy incision was closed with 1-0 polypropylene placed in a simple interrupted suture pattern, and the subcutaneous and dermal layers were routinely closed. Postoperatively, the cat’s renal parameters (urine output and blood urea nitrogen [BUN] and creatinine concentrations), electrolyte concentrations (sodium, potassium, chloride, calcium, magnesium, and bicarbonate), packed cell volume, blood pressure, and body temperature were normal. Postoperative treatment consisted of lactated Ringer’s solution (14 ml/hr), carprofen (2.2 mg/kg subcutaneously once), cefazolin (22 mg/ kg intravenously every eight hours), and morphine (0.01 mg/kg intramuscularly every four hours for 12 hours). A 2.5-mg (25-µg/hr) transdermal fentanyl patch was also applied. In the rst 12 hours after surgery, 20 ml/hr of chyle was withdrawn through the chest tube. The effusion continued but lessened over the next 36 hours. Four days after surgery, the cat was doing well clinically. Despite continued effusion (2.4 ml/hr), we removed the chest tube, discontinued the cefazolin, and discharged the cat with cefadroxil drops (22.7 mg/kg orally every 12 hours for ve days). Histologic diagnosis The histology report described the cystic lesion as being formed of irregular brous tissue without epithelial lining. The luminal surface had areas of bare granulation tissue pseudomembrane and other areas of plump, reactive-appearing broblasts separated by brin. Evidence of chronic hemorrhage was indicated by areas of hemosiderin pigment accumulation within macrophages. The middle and outer layers of the brous capsule exhibited patchy nodular perivascular in ltrates of well-differentiated small lymphocytes. The outer surface of the tissue of the cystic lesion contained mediastinal fat, some of which had evidence of acute hemorrhage. In one area, what appeared to be thyroid follicular epithelial cells were arranged into a solid nodular aggregate. The cells were uniform with minimal anisokaryosis and no atypia or mitotic activity. The lesion also contained several small areas of lymphoid tissue. The histologic diagnosis was a thymic cyst with hemorrhage and mild low-grade in ammation. Follow-up A week after discharge, the cat was reportedly asymptomatic. Physical examination revealed a mild patchy pruritic dermatitis on the left thorax that was possibly secondary to the preoperative preparation or the stockinet that was

Table of Contents Feed for the Digital Edition of Veterinary Medicine - September 2008

Veterinary Medicine - September 2008 Contents Leading Off Practical Matters Idea Exchange A Challengin Case: Thymic Cyst and Recurrent Chylothorax in a Cat 10 Life-Threatening Behavior Myths CE Form Advertiser Index Marketplace/Classifieds Mind Over Miller

Veterinary Medicine - September 2008

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