ASSOCIATION BETWEEN RENAL HYPOECHOIC SUBCAPSULAR THICKENING AND LYMPHOSARCOMA IN CATS

The purpose of this study was to investigate the association between renal hypoechoic subcapsular thickening observed ultrasonographically and the presence of renal lymphosarcoma in cats. The ultrasonography database was retrospectively searched for cats that underwent ultrasound examination and ultrasound guided needle renal aspirate, renal biopsy, or necropsy. One radiologist unaware of the final diagnosis evaluated the images for the presence of hypoechoic subcapsular thickening and other abnormal findings. Fifty-four cats met the inclusion criteria. Hypoechoic subcapsular thickening was found in 21 cats of which 17 had lymphosarcoma; the remaining four cats had a different diagnosis. Eleven out of 33 cats without hypoechoic subcapsular thickening were positive for lymphosarcoma, and the rest had a different diagnosis. There was a significant association between hypoechoic subcapsular thickening and renal lymphosarcoma (P = 0.001). The positive predictive value of hypoechoic subcapsular thickening for lymphosarcoma was 80.9% and the negative predictive value was 66.7%. The sensitivity and specificity of hypoechoic subcapsular thickening for the diagnosis of renal lymphosarcoma were 60.7% and 84.6%, respectively. The results of this study indicate that the presence of hypoechoic subcapsular thickening in feline kidneys is associated with renal lymphosarcoma.     

Ultrasonographic characteristics of splenic and hepatic lymphosarcoma in three horses.

Splenic and hepatic ultrasonography were beneficial for diagnosis of lymphosarcoma in 3 horses with anorexia, weight loss, and lethargy. Ultrasonographic abnormalities of the spleen included a large, complex, hypoechoic mass in 1 horse, multiple well-marginated, hypoechoic nodules in 1 horse, and diffuse hyperechogenicity in another horse. Ultrasonographic abnormalities of the liver included a spherical, hypoechoic nodule in 1 horse and diffuse hyperechogenicity in another. Histologic examination of ultrasound-guided biopsy specimens or aspirates revealed lymphosarcoma. Necropsy findings confirmed diagnosis of lymphosarcoma in all horses. Necropsy findings of the liver and spleen correlated well with antemortem ultrasonographic images.     

ULTRASONIC PATTERNS OF CANINE HEPATIC LYMPHOSARCOMA

Three ultrasonic patterns of canine hepatic lymphosarcoma were found. The first pattern reflected a normal hepatic parenchymal appearance or a slight reduction in echogenicity. The second pattern consisted of anechoic or hypoechoic, poorly marginated lesions. A third pattern was characterized by multiple, round echodensities surrounded by areas of sonolucency. It was concluded that ultrasound is helpful for diagnosis and staging of canine lymphosarcoma with liver involvement and is useful for monitoring the response to chemotherapy.     

CELLULAR FEATURES OF SONOGRAPHIC TARGET LESIONS OF THE LIVER AND SPLEEN IN 21 DOGS AND A CAT

Target lesions are seen in ultrasound images of the liver or spleen as nodules or masses with a hypoechoic rim and a hyperechoic or isoechoic center. To assess the diagnostic significance of finding a target lesion, the cytologic and/or histopathologic findings were reviewed in a series of 21 dogs and a cat that had hepatic and/or splenic target lesions noted during abdominal ultrasonography. Twelve of 16 hepatic target lesions and 5 of 7 splenic target lesions were malignant. In this series, the finding of one or more target lesions in the liver or spleen had a positive predictive value for malignancy of 74%; for the finding of multiple target lesions in one organ, the positive predictive value for malignancy was 81%. Benign lesions associated with target lesions were nodular hyperplasia of the liver and spleen, pyogranulomatous hepatitis, cirrhosis, and chronic active hepatitis.     

ULTRASONOGRAPHIC EVALUATION OF THE PARATHYROID GLANDS IN HYPERCALCEMIC DOGS

Two hyperplastic parathyroid glands and three solitary parathyroid adenomas were identified using high-resolution ultrasonography in five adult dogs with persistent hypercalcemia. Ultrasonographic features of parathyroid adenomas included visualization of a round or oval, 5 mm or larger, hypoechoic mass in the cranial pole of one thyroid lobe. Each mass had well-defined margins between the thyroid gland and parathyroid adenoma, reduced echogenicity of the adenoma compared to surrounding thyroid parenchyma, and distal enhancement. Ultrasonographic features of the hyperplastic parathyroid glands included hypoechogenicity, compared to surrounding thyroid parenchyma, and a size of approximately 2 mm. Hyperplastic parathyroids were well marginated in one dog and poorly marginated in another dog.     

Correlation of ultrasonographic and patho-morphological findings in canine hepatic diseases

Findings of hepatic ultrasonography were analysed in 22 dogs with liver disease and compared with the results of final morphological diagnoses. Ultrasonographic appearance of the liver demonstrated focal alterations in 11 dogs (50 per cent): multifocal lesions in hepatic neoplasia (six), hepatic cirrhosis (one), generalised mycosis (one) and unifocal lesions in haemangiosarcoma (one), nodular hyperplasia (one) and misdiagnosed intestinal invagination (one), Diffuse ultrasonographic alterations were found in 11 dogs (50 per cent): hyperechoic liver of normal/enlarged size in lymphosarcoma (four) and hepatic lipidosis (two); hyperechoic ‘bright’ but small liver in atrophic cirrhosis (two); hypoechoic to normal intensity liver of normal size in liver dystrophy (two) and hepatic venous distension (one). Gallbladder abnormalities were detected in 14 of 20 dogs (70 per cent). Correct ultrasonographic diagnoses were made in 11 dogs (50 per cent). The best results were achieved by combining the clinicolaboratory and ultrasonographic findings, providing a correct diagnosis in 17 dogs (77-3 per cent).     

SONOGRAPHIC AND RADIOGRAPHIC CHANGES ASSOCIATED WITH SPLENIC TORSION IN THE DOG

The clinical, radiographic, and sonographic signs in three dogs with splenic torsion are presented. AH dogs exhibited weight loss, anorexia, and lethargy. Splenomegaly was consistent radiographic finding in two dogs and large ill-defined midabdominal mass was seen in one dog. The spleen was easily imaged sonographically in all dogs. Splenic sonography in two dogs showed diffuse, hypoechoic pattern consistent with splenic congestion. Hilar splenic vessels were enlarged on the sonograms of two dogs.     

CONTRAST HARMONIC ULTRASOUND OF SPONTANEOUS LIVER NODULES IN 32 DOGS

Thirty-two dogs with spontaneous hepatic nodules were given intravenous ultrasound contrast medium (Definity or Sonovue) and imaged with contrast harmonic software on a conventional ultrasound machine system. Digital video images were initially reviewed to describe the perfusion pattern of malignant nodules. The images were reviewed again to test this pattern against all individual nodules. Subjectively, there was improved conspicuity of malignant nodules after contrast enhancement compared with conventional imaging and increased numbers of malignant nodules were often noted. There was decreased conspicuity of benign nodules and no additional nodules were seen after contrast enhancement. There was a highly significant (P < 0.0001) association of malignancy with a hypoechoic nodule at surrounding normal liver peak contrast enhancement. Benign nodules were isoechoic to the surrounding normal liver at peak contrast enhancement. Only one benign nodule (hepatoma) had regions of hypoechogenicity compared with the surrounding normal liver at peak liver contrast enhancement. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were highly significant (P < 0.0001) (100%, 94.1%, 93.8%, 100%, and 96.9%, respectively). No complications or morbidity was noted throughout the course of the study. Contrast harmonic ultrasound appears to be accurate at discriminating between naturally occurring benign and malignant nodules in the liver of dogs.     

SONOGRAPHIC FEATURES OF HISTIOCYTIC NEOPLASMS IN THE CANINE ABDOMEN

The purpose of this retrospective study was to describe the ultrasonographic features of malignant histiocytosis (MH), malignant fibrous histiocytoma, and histiocytic sarcoma in abdominal organs of dogs. The medical records of 18 dogs that had undergone abdominal sonography and had a histopathologic diagnosis of abdominal MH, malignant fibrous histiocytoma, and histiocytic sarcoma were reviewed. The organ most commonly affected was the spleen. MH was the most common followed by histiocytic sarcoma and malignant fibrous histiocytoma. In the spleen there were often multiple hypoechoic nodules with well-defined borders. In one dog, without focal lesions, the spleen was enlarged and hypoechoic. The liver was the second most commonly affected organ. MH was most common followed by histiocytic sarcomas and malignant fibrous histiocytoma. The most common sonographic feature in the liver was the presence of multiple hypoechoic nodules with well-defined borders. One dog without hepatic nodules had a liver that was ultrasonographically enlarged and hypoechoic. MH in the abdominal lymph nodes resulted in hypoechoic lymphadenopathy. Malignant fibrous histiocytoma was the only neoplastic type in the kidneys appearing as a single heteroechoic renal mass with well-defined borders. MH was observed in the stomach of one dog. Sonographically there was a single well circumscribed hypoechoic mass with well-defined borders and abnormal stomach layers. In this study it was not possible to differentiate between MH, malignant fibrous histiocytoma, and histiocytic sarcoma using sonography.     

PREVALENCE AND SIGNIFICANCE OF AN ULTRASONOGRAPHIC COLONIC MUSCULARIS HYPERECHOIC BAND PARALLELING THE SEROSAL LAYER IN DOGS

The muscularis layer of the canine colon has been reported to appear homogeneously hypoechoic on ultrasonography. A hyperechoic band in the muscularis layer paralleling the serosal surface has been observed by authors in routine canine abdominal ultrasound examinations. The purpose of this prospective and retrospective cross‐sectional study was to determine the prevalence of this lesion, characterize its ultrasonographic and postmortem histologic features, and correlate its presence with clinical signs of gastrointestinal disease. In the prospective study, all dogs that underwent routine abdominal ultrasonography by one of two observers during a 4‐week period were included without any exclusion criteria. One observer reviewed ultrasound images and recorded the presence or absence of this lesion and its distribution, e.g. focal (< 2 cm long) or diffuse (> 2 cm long). In the retrospective study, all dogs that had both abdominal ultrasonography and necropsy from January 2011 to December 2013 were included without any exclusion criteria. Histologic examinations were performed by two observers and Masson's trichrome stain was used to identify fibrous collagen. Prevalence for the hyperechoic band was 32% in the prospective and 4.8% in the retrospective sample populations, respectively. The hyperechoic band appeared as diffuse, focal, or a combination of both. Histologic sections were available for six dogs. In a few cases, the lesion corresponded to the presence of fibrous tissue in the myenteric plexus or in the tunica muscularis. None of the dogs had a history of diarrhea. Findings supported the hypothesis that a colonic muscularis hyperechoic band paralleling the serosal layer in dogs could be a normal variant rather than a marker of disease.     

Ultrasonographic findings in abdominal mast cell disease: a retrospective study of 19 patients

A retrospective survey from January 1989 to January 1999 of Tufts University Foster Hospital for Small Animals radiology records of 12 dogs and seven cats with cytologically or histopathologically confirmed abdominal mast cell disease was performed. Ultrasound changes in hepatic mast cell infiltration in dogs included a subjective increase in size, a diffuse increase in echogenicity, and one or more hypoechoic nodules. Ultrasound findings in the affected canine spleen included one or more hypoechoic nodules and a subjective increase in size. Two ultrasonographically unremarkable canine livers and one unremarkable spleen were found to be infiltrated by mast cells. The mast cell-infiltrated feline spleen was subjectively increased in size, mottled, irregular, or contained nodules. The affected lymph nodes in both dogs and cats were hypoechoic or inhomogeneous, subjectively increased in size, and rounded. Gastrointestinal involvement in cats was characterized by a thickened ileocecocolic junction or colon with loss of wall layering. Mast cells were not found in the gastrointestinal tract in any dog. One dog with mast cell infiltrate of the kidneys had multiple hypoechoic nodules in the cortex that distorted the outer contour of the kidney. Although these findings are not specific to the disease in either species, abdominal ultrasound is considered a useful tool for determining the extent of disease in small-animal patients with mast cell tumor if used in conjunction with histopathology or cytology.     

Ultrasonographic features of splenic lymphosarcoma in dogs: 12 cases (1980-1986)

The ultrasonographic appearance of the spleen and adjacent organs in 12 dogs with splenic lymphosarcoma was reviewed. Poorly marginated hypoechoic to anechoic nodules (4 mm to 3 cm in diameter) were found in all dogs. The anechoic nodules did not result in reflective shadowing or acoustic enhancement of the underlying tissues. The remainder of the splenic parenchyma appeared relatively hypoechoic when compared with the liver or renal cortices in 9 dogs. Recognition of this ultrasonographic pattern appears to be a useful diagnostic tool. Needle aspiration guided ultrasonographically will then enable histologic confirmation of lymphosarcoma.     

HEPATIC ULTRASONOGRAPHIC AND PATHOLOGIC FINDINGS IN DOGS WITH CANINE SURPERFICIAL NECROLYTIC DERMATITIS

A unique, "honeycomb" pattern was found on ultrasonographic evaluation of the liver of 5 dogs with canine superficial necrolytic dermatitis (hepatocutaneous syndrome). This pattern consisted of variably-sized, hypoechoic regions measuring 0.5–1.5 cm in diameter surrounded by highly echogenic borders. Histologically, the hypoechoic regions corresponded to distinct regenerative nodules bounded by severely vacuolated (fat-laden) hepatocytes, numerous bile ductules, and a network of reticulin and fine collagen fibers representing remnants of collapsed hepatic lobules. While certain features of the architectural disruption were characteristic of cirrhosis, the lesion lacked the extensive fibrosis and reduced liver size usually associated with chronic cirrhosis. To our knowledge, this hepatic ultrasonographic pattern has only been seen with canine superficial necrolytic dermatitis. Therefore, it appears to be pathognomonic in a dog with questinable skin lesions. A liver biopsy is required to confirm the unique histopathologic features of the hepatopathy found in this syndrome.     

Ultrasonographic evaluation of renal parenchymal diseases in dogs: 32 cases (1981-1986)

The medical records of 32 dogs with microscopically proven renal parenchymal disease were evaluated to characterize the associated ultrasonographic patterns and to assess the contribution of ultrasonography to the diagnosis and management in each case. Ultrasonography provided additional information on internal renal architecture in 18 dogs with radiographic evidence of structural abnormality. Ultrasonography determined the renal origin of 2 abdominal masses, defined the extent and distribution of neoplastic disease in 6 dogs, and identified kidneys not seen on survey radiographs or excretory urograms in 5 dogs because of decreased abdominal contrast or poor function. The ultrasonographic patterns were most specific for focal and multifocal or diffuse neoplasia. Ultrasonographic findings were least specific for diffuse parenchymal disease without architectural disruption such as glomerulo/interstitial nephritis, renal tubular necrosis, and nephrocalcinosis. In these cases, biopsy was recommended. Six interpretive errors were made. Four of these errors were related to the overestimation of renal pelvic and diverticular size because of confusion with medullary papilla. Two errors occurred in the diagnosis of renal lymphosarcoma, one of which was interpreted to be pyelonephritis. The other was an interpretive dilemma because of absence of hypoechoic multifocal nodules. Renal tubular necrosis was confirmed in this case.     

ULTRASONOGRAPHY AS A DIAGNOSTIC AID IN PLEURAL EFFUSION OF HORSES*

Three horses with clinical signs compatible with pleural effusion were examined with diagnostic ultrasound. In one of the three horses, confirmed septic pleural effusion was monitored with ultrasound during a successful treatment regimen. Eficacy of thoracentesis and detection of recurrence of fluid were readily determined. In the second horse, diagnosis of diffuse pleural neoplasia (lymphosarcoma) was made. In the third horse presented for pleural effusion, the effusion was documented and concurrent ascites detected with ultrasound. Carcinomatosis was found at necropsy. Ultrasound examination proved to be a sensitive, noninvasive modality useful in diagnosis and treatment of pleural effusion.     

Follow-up studies by peroral gastric biopsies and necropsy in vomiting dogs.

The results of follow-up studies in 139 vomiting dogs are presented. Follow-up studies were performed by biopsies in 34 dogs, by biopsies and necropsy in six dogs and by necropsy only in 99 dogs. The times between the first and the last series of biopsies varied from three to 1042 days and from one to 656 days between the first series of biopsies and necropsy. From the 55 dogs with gastritis in the first series of biopsies, 35 also showed gastritis in the following biopsies or at necropsy. These were mainly severe types of gastritis such as diffuse, hypertrophic or atrophic. Ten dogs with superficial gastritis showed no gastric changes at necropsy, two dogs had edema only and three dogs had gastric changes other than gastritis, such as multiple polyps. In general, carcinoma and lymphosarcoma were found in the biopsies as well as at necropsy, but in three cases of terminal carcinoma only gastritis had been diagnosed initially. In 35 dogs the first series of gastric biopsies showed no pathological changes, but in 22 of these dogs gastritis, ulceration, fibrosis, atrophy, gastric dilation with local necrosis, and perforation or lymphosarcoma of the submucosa were found in the second series of biopsies or at necropsy. Several dogs which did not have gastric changes at necropsy had enteritis or intestinal lymphosarcoma.     

ULTRASONOGRAPHIC FINDINGS IN CHOLECYSTOKININ-INDUCED PANCREATITIS IN DOGS

Pancreatitis can be induced in dogs by intravenous infusion of supraphysiologic doses of synthetic cholecystokinin octapeptide (CCK-8). Eight anesthetized female beagles were given either CCK-8 or saline in a randomized, blinded fashion and had abdominal ultrasonography to study the development of pancreatic lesions. Pancreatic lesions were apparent 2 hours after the start of CCK-8 infusion and included swelling, interlobular and subcapsular fluid accumulation and patchy hypoechogenicity of the gland parenchyma. CCK-8 had a variable effect on gallbladder emptying. No signs of biliary obstruction or duodenal lesions were identified. Dogs given CCK-8 had severe edematous pancreatitis at necropsy six hours after the start of the infusion. Compared to the oleic acid model of pancreatitis, CCK-8 infusion induces a rapid onset of pancreatitis and an ultrasonographic appearance that reflects diffuse edema of the gland. The short time-scale of the experiment may account for the relative absence of secondary lesions affecting the biliary tract or duodenum compared to the naturally-occurring disease.     

MULTICENTRIC LYMPHOSARCOMA IN A DOG WITH MULTIPLE-SITE SKELETAL INVOLVEMENT

In this report the authors describe an unusual clinical presentation of lymphosarcoma (LSA) in a dog. A 9-year-old, neutered male, Golden Retriever was presented with a primary complaint of sudden onset of tetraparesis. Routine survey radiographs revealed multiple-site bony lesions and the histology revealed a diagnosis of LSA with diffuse skeletal and soft tissue involvement. The dog responded poorly to medical management and was euthanized on day two due to poor prognosis. Malignant LSA of the bone is a rare extranodal clinicopathologic entity and presents both a diagnostic and therapeutic hurdle. Reports of this kind are sparse and currently no optimal treatment for this entity has been determined.     

NODULAR FAT NECROSIS IN THE FELINE AND CANINE ABDOMEN

The radiographic appearance of nodular fat necrosis is described in ten cats and one dog. The most common radiographic sign was the presence of a focal mineralized circular to oval soft tissue mass in the abdominal fat as present in 9 cats. These masses had a distinct eggshell-like rim encapsulating the lesion. In one cat and one dog multiple masses were present, without radiographic signs of mineralization. Abdominal ultrasound was performed in three cats and one dog, findings included the presence of hyperechoic masses with associated acoustic shadowing, some with a hypoechoic centre. Almost all animals were old and obese. In three cats and one dog, changes were confirmed with biopsy or post mortem examination. Lesions having the appearance of those in this paper are most likely incidental findings and should not be confused with abdominal masses of neoplastic origin. Ultrasound can be helpful in identifying such lesions.