ULTRASOUND-GUIDED FINE-NEEDLE ASPIRATION BIOPSY OF BONE LESIONS: A PRELIMINARY REPORT

The purpose of this preliminary study was to determine the feasibility of ultrasound-guided fine-needle aspiration biopsy of suspected neoplastic lesions of bone. Ultrasound-guided fine-needle aspiration biopsy samples were obtained in 23 patients (22 dogs and one cat) with radiographic evidence of a destructive or destructive/productive bone lesion. The lesions were located in the appendicular skeleton in 20 patients and in the axial skeleton in three. Histopathology from tissue core biopsies and/or necropsy was not deemed necessary in 11 patients where ultrasound-guided fine-needle aspiration biopsy results were conclusive for neoplasia. A cytologic diagnosis from ultrasound-guided fine-needle aspiration biopsy was confirmed by histologic samples obtained at surgery or necropsy in five patients. In one of these five, ultrasound-guided fine-needle aspiration biopsy samples were diagnostic for sarcoma when tissue-core biopsy was inconclusive. Both ultrasound-guided fine-needle aspiration biopsy and tissue core biopsy techniques were inconclusive in one patient. Ultrasound-guided fine-needle aspiration biopsy samples were nondiagnostic in five patients where a follow-up histopathologic diagnosis of neoplasia was made. It was concluded that ultrasound-guided fine-needle aspiration biopsy of bone, if diagnostic, may help avoid the need for a tissue-core biopsy in some instances. However, a negative ultrasound-guided fine-needle aspiration biopsy sample does not rule out neoplasia. A negative ultrasound-guided fine-needle aspiration biopsy should be followed by a tissue-core biopsy and histologic analysis in all patients. Ultrasound-guided fine-needle aspiration biopsy seems to be a promising technique for the diagnosis of bone lesions.     

Correlation of ultrasonographic appearance of lesions and cytologic and histologic diagnoses in splenic aspirates from dogs and cats: 32 cases (2002-2005)

OBJECTIVE: To determine the accuracy of cytologic diagnosis, compared with histologic diagnosis, in determination of disease in ultrasound-guided fine-needle aspirates of splenic lesions. DESIGN: Retrospective study. SAMPLE POPULATION: Splenic specimens from 29 dogs and 3 cats. PROCEDURES: Records were searched for dogs and cats that had undergone ultrasound-guided splenic aspiration. Criteria for inclusion were ultrasonographic identification of splenic lesions and cytologic and histologic evaluation of tissue from the same lesion. Cytologic samples were obtained by fine-needle aspiration, and histologic specimens were obtained via surgical biopsy, ultrasound-guided biopsy, or necropsy. RESULTS: Cytologic diagnoses corresponded with histologic diagnoses in 19 of 31 (61.3%) cases and differed in 5 of 31(16.1%) cases, and 1 aspirate was inadequate for evaluation. In 7 of 31 (22.6%) cases, histologic evaluation of tissue architecture was required to distinguish between reactive and neoplastic conditions. On the basis of histologic diagnosis in 14 animals with nonneoplastic conditions, the cytologic diagnosis was correct in 11 cases, not definitive in 2 cases, and incorrect in 1 case. In 17 animals with malignant neoplastic diseases, the cytologic diagnosis was correct in 8 cases, not definitive but consistent with possible neoplasia in 5 cases, and incorrect in 4 cases. Multiple similar-appearing nodules were significantly associated with malignancy, whereas single lesions were more often benign. CONCLUSIONS AND CLINICAL RELEVANCE: Ultrasound-guided aspiration of splenic lesions is a minimally invasive tool for obtaining specimens for cytologic evaluation. Although cytologic diagnoses often reflect histologic results, if missampling or incomplete sampling occurs or tissue architecture is required to distinguish between reactive and neoplastic conditions, accurate diagnosis with fine-needle aspiration may not be possible.     

THE TECHNIQUE OF PERCUTANEOUS ULTRASOUND GUIDED FINE-NEEDLE ASPIRATION BIOPSY AND AUTOMATED MICROCORE BIOPSY IN SMALL ANIMAL GASTROINTESTINAL DISEASES

Techniques for obtaining percutaneous ultrasound-guided biopsies of the gastrointestinal tract were evaluated. The efficacity of ultrasonographic detection of gastrointestinal lesions has been established in veterinary medicine. Percutaneous ultrasound-guided aspiration biopsies were performed using either a 22 gauge spinal needle or a 20 gauge Westcott needle. The microcore automated biopsy was performed using a 18 gauge Tru-cut-like needle, assisted by an automated biopsy gun. These techniques are rapid, and easily performed. The techniques were considered safe for the patient, no complications such as hemorrhage, peritonitis or abscessation have occured in our study. These techniques are of particular interest when lesion can not be biopsied successfully by endoscopy and when surgical resection is not recommended.     

FLUOROSCOPICALLY GUIDED PERCUTANEOUS FINE-NEEDLE ASPIRATION BIOPSY OF THORACIC LESIONS IN DOGS AND CATS

Forty-eight fine-needle aspiration biopsy specimens of intrathoracic lesions were obtained with a Westcott needle by localizing needle placement using TV-monitored, image-amplified fluoroscopy and by detecting changes in tactile sensation. Thiryt-five lesions were pulmonary in origin and 13 were within the mediastinum. Most biospy specimens were obtained with the patients sedated, however, general anesthesia was used in one patient to prevent movement that could have resulted in puncture of a critical structure. The only clinical and radiographic complication from this procedure was pneumothorax, occurring in eight dogs and resulting in one death. Definitive diagnoses were made from tissue obtained from 37 of the 48 lesions sampled for a sensitivity rate of 77.1%. Fine-needle aspiration biopsy was found to be a simple, safe, and accurate diagnostic technique.     

ULTRASOUND-GUIDED FINE-NEEDLE ASPIRATION

A simple and inexpensive modification of the ultrasound-guided fine-needle aspiration biopsy technique using an extension tube attached to the needle is described. One operator can easily manipulate the ultrasound transducer and biopsy needle while monitoring the entire procedure. This simple modification was found to facilitate ultrasound-guided fine-needle aspiration.     

NEEDLE-TRACT IMPLANTATION FOLLOWING US-GUIDED FINE-NEEDLE ASPIRATION BIOPSY OF TRANSITIONAL CELL CARCINOMA OF THE BLADDER, URETHRA, AND PROSTATE

Localized tumor implantation of the ventral abdominal wall was found at 2, 5, and 8 months following percutaneous ultrasound-guided fine-needle aspiration biopsy (FNAB) of transitional carcinoma of the bladder, urethra, or prostate in 3 dogs. To our knowledge this complication has not been reported in dogs following FNAB. Despite the rarity of needle-tract implantation, the potential for this complication with transitional cell carcinomas is apparently not negligible and warrants consideration. We recommend traumatic urethral catheterization to obtain a cytologic diagnosis of potential transitional cell carcinomas of the lower urinary tract or prostate whenever possible until more information becomes available. However, needle-track implantation is so rare that it should not influence the decision to perform a percutaneous FNAB if the urethra cannot be catheterized.     

ULTRASONOGRAPHIC APPEARANCE OF SPLENIC DISEASE IN 101 CATS

The sonographic findings in 101 cats with splenic abnormalities are presented. Diagnosis was made by ultrasound-guided fine needle aspirate or fine-needle biopsy (n = 91), ultrasound-guided core biopsy (n = 1), surgical core biopsy (n = 1), or necropsy (n = 10). Two cats had more than one diagnostic procedure (fine needle aspirate and necropsy or core biopsy and necropsy). The splenic abnormalities included lymphosarcoma (n = 30), mast cell tumor (n = 27), extramedullary hematopoiesis and/or lymphoid hyperplasia (n = 27), epithelial tumors (n = 6), mesenchymal tumors (n = 4), malignant histiocytosis (n = 2), myeloproliferative disease (n = 2), pyogranulomatous inflammation (n = 2), erythroleukemia (n = 1), eosinophilic syndrome (n = 1), hematoma (n = 1), and granulomatous splenitis (n = 1). Three cats had more than one splenic abnormality (mast cell tumor and metastatic carcinoma, pyogranulomatous inflammation and lymphoid hyperplasia, histiocytic lymphosarcoma, and lymphoid hyperplasia). Pathognomonic changes were not seen for any of the diseases.     

COMPUTED TOMOGRAPHY-GUIDED FINE-NEEDLE ASPIRATE AND TISSUE-CORE BIOPSY OF INTRATHORACIC LESIONS IN THIRTY DOGS AND CATS

Medical records and computed tomography (CT) images were reviewed retrospectively for 30 animals (27 dogs, two cats, one cougar) in which CT-guided intrathoracic fine-needle aspirates (FNA) (12), core biopsies (10) or both (8) were performed. Sample interpretation was listed as diagnostic or nondiagnostic and nonneoplasia or neoplasia. Diagnostic results were inconclusive in 35% FNA and 17% biopsies. FNA and biopsy interpretations were in agreement in seven patients, one nonneoplasia, and six neoplasia. A clinical diagnosis was made in 65% FNA and 83% biopsies. When 18 patients with confirmed diagnoses were used, overall accuracy for diagnosis was 92% for FNA and biopsy and the sensitivity for neoplasia was 91% using fine needle aspirate and 80% using biopsy. Complications seen on CT images were noted in 43% of patients, four pneumothorax, five pulmonary hemorrhage, and four with both. No clinical manifestations were noted and treatment was not necessary. Significant correlation was noted between complications and penetration of aerated lung, but not with lesion location, type of disease, method of sampling, width of mass and depth of aerated lung penetrated. CT-guided sampling is relatively safe and useful in the diagnosis of intra-thoracic lesions, especially neoplasia. FNA samples are nondiagnostic more often than biopsy samples. Sub-clinical pneumothorax and hemorrhage are common when aerated lung is penetrated.     

SAFETY OF PERCUTANEOUS ULTRASOUND–GUIDED BIOPSY OF RENAL ALLOGRAFTS IN THE CYNOMOLGUS MONKEY: RESULTS OF 348 CONSECUTIVE BIOPSIES

The safety of a technique for ultrasound-guided biopsy of renal allografts was evaluated based on 348 consecutive procedures in cynomolgus monkeys. A spring-loaded biopsy device with an 18G tru-cut biopsy needle was used to biopsy renal allografts in 139 cynomolgus monkeys performed either on clinical indication (n = 95 animals) or as serial protocol biopsies (n = 44 animals) for a total of 348 biopsies. Monkeys having serial biopsies received between 3-9 biopsies per animal. All others received non-protocol biopsies that were performed on clinical indication, and the range was 1-15 biopsies per animal. No life-threatening complications or deaths occurred and there were no clinically detectable minor complications such as macrohematuria. Self-limiting complications such as small arteriovenous fistulas (n = 4, 3-5 mm large) were detected with Doppler ultrasound and resolved hemodynamically after 2-4 weeks. Three animals developed hematomas ranging 4 mm-2 cm in diameter and were no longer sonographically evident 2-4 weeks later. Ultrasound-guided biopsy of renal allografts can be performed with a high degree of safety in small (3-5 kg) laboratory animals such as the cynomolgus monkey and provides a valuable tool for renal transplantation research. Even when cores were taken at two week intervals no major complications occurred and only rarely were clinically irrelevant complications detected. Experience with diagnostic ultrasound, both gray scale and Doppler, is important for both safety and the recognition of complications that may arise.     

ULTRASONOGRAPHY OF ALIMENTARY LYMPHOSARCOMA IN THE CAT

Clinical, radiological and ultrasonographic findings from 22 cats with gastrointestinal lymphosarcoma were reviewed. The most common clinical findings were anorexia, weight loss, vomiting, lethargy, depression, fever, anemia and a palpable abdominal mass. Abdominal radiographs of 12 cats revealed a mass associated with the gastrointestinal tract and/or mesentery, and decreased serosal detail, suggestive of peritoneal effusion. The most common ultrasonographic finding was transmural gastric or intestinal thickening associated with loss of normal wall layering, reduced wall echogenicity and localized hypomotility. As is noted in people, other patterns such as transmural-segmental, transmural-nodular, transmural-bulky and mucosal infiltration were represented. In 3 cats, mesenteric lymph-adenopathy was responsible for most of the mass-effect. Fine-needle aspiration biopsy, automated microcore biopsy, endoscopic biopsy or necropsy confirmed the diagnosis of lymphosarcoma in all cats. Chemotherapy was instituted in 19 cats. Only 6 cats had a complete response to treatment. The results of this study indicate that ultrasonography is a valuable tool for the diagnosis of feline alimentary lymphosarcoma and that biopsies can be obtained under ultrasonographic guidance.     

A COMPARISON OF MANUAL AND AUTOMATIC ULTRASOUND-GUIDED BIOPSY TECHNIQUES

A manual, ultrasound-guided biopsy technique was compared to a new automatic method using a new biopsy device. The liver and the left kidney of 10 dogs were biopsied using the two methods. The specimens from the biopsies were compared for size and quality. Results demonstrate that larger and higher quality samples were obtained with the new automatic method.     

Sensitivity of Tru-cut and fine needle aspiration biopsies of liver and kidney for diagnosis of feline infectious peritonitis

BACKGROUND: The detection of typical lesions and feline coronavirus (FCoV) antigen in tissues is the only conclusive method for making a diagnosis of feline infectious peritonitis (FIP). A positive result using Tru-cut biopsy (TCB) and fine-needle aspiration biopsy (FNAB) has high diagnostic specificity, but information about the capacity of these techniques to correctly identify cats with FIP lesions is not available. OBJECTIVES: The diagnostic sensitivity of TCB and FNAB for detecting liver and kidney histologic lesions caused by FIP was evaluated. METHODS: TCB and FNAB specimens collected mainly at necropsy from 25 cats with FIP were analyzed. Diagnostic sensitivity was calculated on the basis of the number of false-negative and true-positive specimens, compared with the number of organs bearing histologic lesions of FIP. RESULTS: Diagnostic sensitivity was higher for hepatic TCB (64%) and FNAB (82%) than for renal (39% and 42%, respectively) procedures. A high percentage of renal cytologic and TCB specimens were inadequate. Combined analysis of TCB and FNAB specimens collected from the same organ increased the diagnostic sensitivity for liver (86%) and kidney (48%). The sensitivity of immunohistochemical/cytochemical analysis was low (11-38% depending on the technique), probably due to variable distribution of feline coronavirus in the lesions. CONCLUSION: Biopsy of liver and kidney can correctly identify FIP lesions. However, false-negative results or inadequate samples occur with moderate frequency, especially for immunochemical analysis. Diagnostic sensitivity may be increased when both TCB and FNAB specimens from the same organ are examined.     

Evaluation of the cytologic diagnosis of canine prostatic disorders

BACKGROUND: Canine prostatic disease is commonly investigated using cytologic techniques, especially now that ultrasound-guided fine needle cell aspiration (US-FNA) is widely available. Few studies, however, have evaluated the diagnostic accuracy of prostatic cytology. OBJECTIVE: The purpose of this study was to evaluate the usefulness of cytologic investigation of prostatic disease using US-FNA and other methods in comparison with histopathologic diagnosis. METHODS: Cytologic and histopathologic specimens of prostate or paraprostatic tissue from 25 adult dogs were retrospectively evaluated. Cytologic samples were obtained by US-FNA, prostatic massage, or direct impression smears or aspirates of tissue at surgery. Histopathologic sections were obtained from tissue collected by biopsy or at necropsy. RESULTS: Cytologic diagnoses were categorized as nondiagnostic (n = 2); cyst (n = 1); squamous metaplasia (n = 2); inflammation (n = 4); benign prostatic hyperplasia (BPH; n = 5); inflammation and BPH (n = 3); inflammation, BPH, and neoplasia (n = 1); inflammation and neoplasia (n = 3); and neoplasia (n = 4). Cytologic diagnoses agreed with final histologic diagnoses in 20 of the 25 cases (80%). Of those samples collected by US-FNA, 75% were concordant. Four samples obtained by US-FNA and 1 sample obtained by prostatic massage and wash had discordant results. CONCLUSIONS: The results of this study suggest strong agreement between cytologic and histopathologic diagnoses for prostatic conditions. Discordance in results obtained by US-FNA usually was the result of the pathologic process rather than a failure to obtain an appropriate sample.     

ULTRASOUND-GUIDED PERCUTANEOUS LIVER BIOPSY IN SNAKES

Percutaneous ultrasound-guided liver biopsies were conducted in 15 snakes using 18-gauge automatic biopsy devices. The liver samples collected ranged in size from 1.16 ± 0.40 mm to 8.3 ± 0.55 mm. Upon histologic examination, all biopsy samples were of diagnostic quality. Anesthesia with complete immobilization of the snake was necessary to allow proper selection of the target site and limit complications associated with biopsy collection. Percutaneous ultrasound-guided liver biopsy is a rapid, minimally invasive method for collecting liver tissue in snakes.     

SAFETY AND CORRELATION OF TEST RESULTS OF COMBINED ULTRASOUND‐GUIDED FINE‐NEEDLE ASPIRATION AND NEEDLE CORE BIOPSY OF THE CANINE SPLEEN

The safety and diagnostic value of combined splenic fine‐needle aspiration (FNA) and needle core biopsy (NCB) is unknown. Forty‐one dogs with splenic lesions were studied prospectively. Safety was assessed in 38 dogs and no complications were encountered. Initially, clinical and anatomic pathologists reviewed each FNA and NCB sample, respectively, without knowledge of the other's results. Diagnoses were categorized as neoplastic, benign, inflammatory, normal, or nondiagnostic. The level of agreement between sampling methods was categorized as complete, partial, disagreement, or not available. Test correlation was performed in 40 dogs. Nondiagnostic results occurred in 5/40 NCB (12.5%) and no FNA samples. Neoplasia was diagnosed in 17/40 dogs (42.5%), benign changes in 20/40 dogs (50%), inflammatory disorders in 0/40 dogs, and normal 2/40 dogs (5%). One of the 40 dogs (2.5%) had a diagnosis that was equivocal for neoplasia on both tests and therefore was not categorized. Of the 35 dogs that had diagnostic samples, cytopathologic and histopathologic diagnoses agreed completely in 18/35 dogs (51.4%), partially in 3/35 dogs (8.6%), and were in disagreement in 14/35 dogs (40.0%). Pathologists collaboratively reviewed diagnoses that were in disagreement or partial agreement and altered their individual diagnoses in 6/17 dogs (35.3%) to be within partial or complete agreement, respectively. Percutaneous FNA and NCB can be performed safely in dogs with sonographic splenic changes. Results suggest that adding NCB to FNA provides complementary information in dogs with suspected splenic neoplasia. This combined protocol may improve detection of splenic neoplasia and provide neoplastic subclassification.     

Comparison of core needle biopsy and fine-needle aspiration of enlarged peripheral lymph nodes for antemortem diagnosis of enzootic bovine lymphosarcoma in cattle

OBJECTIVE: To determine whether antemortem core needle biopsy and fine-needle aspiration of enlarged peripheral lymph nodes could be used to distinguish between inflammation and lymphosarcoma in cattle. DESIGN: Prospective study. ANIMALS: 25 cattle with enlarged peripheral lymph nodes. PROCEDURES: Antemortem biopsies of the selected lymph nodes were performed with an 18-gauge, 12-cm core needle biopsy instrument. Fine-needle aspirates were performed with a 20-gauge, 4-cm needle. Specimens were analyzed by pathologists who were unaware of clinical findings and final necropsy findings, and specimens were categorized as reactive, neoplastic, or nondiagnostic for comparison with necropsy results. RESULTS: Sensitivity and specificity of core needle biopsy ranged from 38% to 67% and from 80% to 25%, respectively. Sensitivity of fine-needle aspiration ranged from 41% to 53%, and specificity was 100%. Predictive values for positive test results ranged from 77% to 89% for core needle biopsy and were 100% for fine-needle aspiration. Predictive values for negative test results were low for both core needle biopsy and fine-needle aspiration. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that core needle biopsy and fine-needle aspiration can aid in the antemortem diagnosis of bovine enzootic lymphosarcoma. Results of fine-needle aspiration of enlarged peripheral lymph nodes were more specific and more predictive for a positive test result than were results of core needle biopsy.     

Getting to the point: indications for fine-needle aspiration of internal organs and bone

The technique of fine-needle biopsy (fine-needle aspiration or fine-needle fenestration) for cytologic evaluation can be extended to many sites beyond the traditional lymph node and skin. Intra-abdominal, intrathoracic, and bone lesions can be easily and rapidly evaluated cytologically. Percutaneous fine-needle aspiration and fine-needle fenestration are useful, accurate, and inexpensive techniques with a rapid turnaround time, and outpatient applicability. For most pets, these minimally invasive techniques do not require anesthesia or analgesia. Although risks are inherent with any invasive procedure, complications are uncommon even with visceral and intrathoracic fine-needle biopsy. Attention to appropriate technique and close patient monitoring minimize the morbidity and improve the diagnostic utility. The low cost, low risk, minimal invasiveness, and high diagnostic yield make fine-needle biopsy particularly attractive to clients. In combination with ultrasound guidance and newer staining techniques, these diagnostic procedures are invaluable to the veterinary clinician.     

CT-GUIDED BRAIN BIOPSY USING A MODIFIED PELORUS MARK III STEREOTACTIC SYSTEM: EXPERIENCE WITH 50 DOGS

This report describes the results of CT-guided stereotactic brain biopsies performed on 50 consecutive dogs using a modified Pelorus Mark III Stereotactic System. Based on available histopathologic samples (stereotactic biopsy [n = 50], surgery [n = 17], necropsy [n = 9]) the patient population consisted of 34 dogs with primary brain tumors, 2 with invasive nasal adenocarcinomas, and 13 with non-neoplastic brain lesions. Brain tissue was not obtained from one dog. In 22 dogs a final diagnosis was made from tissue subsequently obtained from surgical resection or at necropsy. The final diagnosis was in agreement with the stereotactic biopsy diagnosis in 20 of these 22 dogs. In 17 other dogs without follow-up, stereotactic biopsy provided a diagnosis of a specific primary brain tumor subtype. Postoperative complications associated with the biopsy procedure were assessed in 41 dogs. The other 9 dogs either went directly to surgery (n = 7) or were killed (n = 2) immediately after the biopsy procedure. Thirty-six dogs recovered without apparent clinical complications. Postoperative clinical complications in the remaining 5 dogs included transient epistaxis (1 dog), transient exacerbation of cerebellar signs (1 dog), obtundation progressing to coma (1 dog), and medically uncontrollable seizures (2 dogs). The latter 3 dogs with severe neurologic complications all had large primary brain tumors and had been receiving high doses of phenobarbital and glucocorticoids to control seizures at the time of biopsy. These results suggest that this CT-guided biopsy procedure can provide an accurate pathologic diagnosis of brain lesions detected by CT and MR neuroimaging. Further refinement of both technique and case selection is expected to reduce the rate of clinical complications and to improve the accuracy of the procedure.     

CAN SONOGRAPHIC FINDINGS PREDICT THE RESULTS OF LIVER ASPIRATES IN DOGS WITH SUSPECTED LIVER DISEASE?

While abdominal ultrasound and ultrasound-guided fine-needle aspiration cytology are often combined to help determine the type of liver disease in dogs, little is known about the relationship that may exist between the results of these tests. We hypothesized that specific sonographic findings, or combinations of findings, may predict results of liver ultrasound-guided fine-needle aspiration cytology. Hepatic and extrahepatic sonographic findings were recorded prospectively using a standardized form in 70 dogs with clinically suspected liver disease and in which liver ultrasound-guided fine-needle aspiration cytology was performed. The predictive value of sonographic findings in regard to the category of cytology results was assessed with stepwise logistic regression analysis. Sonographic detection of a hepatic mass (≥3 cm; risk ratio [RR] 3.83, 95% Wald confidence intervals [95% CI] 2.42–3.93, P =0.0036), ascites (RR 3.82, 95% CI 1.94–4.28, P =0.0044), abnormal hepatic lymph node(s) (RR 3.01, 95% CI 1.22–4.88, P =0.0262), and abnormal spleen (RR 3.26, 95% CI 1.20–3.85, P =0.0274) were the most predictive of liver neoplasia on cytology. Conversely, sonographic detection of hepatic nodules (<3 cm; RR 1.97, 95% CI 0.95–2.96, P =0.0666) was most predictive of vacuolar hepatopathy on cytology. In dogs with suspected liver disease, several sonographic findings, alone or combined, are thus predictive of liver ultrasound-guided fine-needle aspiration cytology results. In the light of the fact that ultrasound-guided fine-needle aspiration cytology of the liver has limitations, these predictabilities could influence the selection of diagnostic tests to reach a reliable diagnosis.     

ULTRASONOGRAPHIC APPEARANCE OF FELINE ALIMENTARY LYMPHOMA

Abdominal ultrasonography was performed in seven cats with intestinal lymphoma and four cats with gastric lymphoma. Ultrasonographic abnormalities included the presence of a hypoechoic mass associated with the gastrointestinal tract, focal or diffuse thickening of the gastric wall, symmetric thickening of the bowel wall, loss of the normal layered appearance of the gastrointestinal wall, and abdominal lymphadenopathy. The thickness of the stomach wall ranged from 8 to 22 mm in cats with gastric lymphoma, and the thickness of the bowel wall ranged from 5 to 20 mm in cats with intestinal lymphoma. Fine needle aspiration of a gastrointestinal lesion was performed without complication in six cats, and was diagnostic for lymphoma in five out of six. Results of this study indicate that ultrasonography is an effective noninvasive means of identifying lesions consistent with alimentary lymphoma in cats.