Research Update: Accuracy of splenic aspirate cytologic diagnoses

In this retrospective study from a university veterinary hospital, the case records of 29 dogs and three cats were reviewed to determine the diagnostic accuracy of cytologic evaluation of splenic aspirates gathered by using ultrasound-guided fine-needle aspiration compared with histologic evaluation of specimens obtained by using surgical biopsy (10 animals) or ultrasound-guided biopsy (2) or at necropsy (21).

The median age of patients was 10 years (range = 4 to 16 years), and golden retrievers were the most frequently represented breed (7). Neoplastic metastasis screening was the most common reason for ultrasonographic examination. Aspiration was done with a 22-ga, 1.5-in-long needle. No complications of aspiration were noted.

Cytologic diagnosis corresponded with histologic diagnosis in 61% of the cases and differed in 16%. In 23% of the cases, histologic examination was required to distinguish between reactive and neoplastic conditions. Of the 17 animals with malignant neoplasia, the cytologic diagnosis was correct in eight cases, consistent but not definitive in five, and incorrect in four. Of the 14 animals with non-neoplastic conditions, the cytologic diagnosis was correct in 11 cases, not definitive in two cases, and incorrect in one case. Additionally, the authors found that multiple discrete lesions with a similar ultrasonographic appearance were significantly associated with malignancy; single lesions were more often benign.

The authors concluded that ultrasound-guided aspiration was safe, technically easy to perform, and yielded accurate information in most, but not all, instances. No comments regarding splenic aspirates in cats were made because of the small number (3) in the study.

COMMENTARY

Abdominal ultrasonography is useful in diagnosing splenic diseases, although conclusive diagnosis invariably requires tissue examination. Percutaneous ultrasound-guided aspiration or biopsy provides a minimally invasive alternative approach to open surgical biopsy. This study's results support the technical ease and safety of performing needle aspiration. As with any focal sampling technique, the data may not be conclusive in all cases. It is worthwhile to note that this study confirmed other reports documenting benign lesions (regenerative nodules, hematoma) as being more common than lymphoma or hemangiosarcoma in dogs.

Jones JC, Ober CP. Computed tomographic diagnosis of nongastrointestinal foreign bodies in dogs. J Am Anim Hosp Assoc 2007;43:99-111.

The information in "Research Updates" was provided by Veterinary Medicine Editorial Advisory Board member Joseph Harari, MS, DVM, DACVS, Veterinary Surgical Specialists, 21 E. Mission Ave., Spokane, WA 99202.

Joseph Harari, MS, DVM, DACVS