Use of 3D ultrasonography in diagnosing ovarian adenocarcinoma in a common mynah (Acridotheres tristis).
Key words: hepatomegaly, ovarian tumor, 3-dimensional ultrasonography, avian, common mynah, Acridotheres tristis
A 12-year-old female common mynah (Acridotheres tristis) was presented to the pet bird clinic of the Faculty of Veterinary Medicine, University of Tehran, for depression, anorexia, respiratory distress, incoordination, and coelomic enlargement. Physical examination revealed relatively obese body condition, abdominal distention, severe dyspnea, and subjective hepatomegaly.
Radiographic examination was performed in lateral and ventrodorsal positions. Hepatomegaly and a dorsal caudal coelomic mass were observed on survey radiographs (Fig 1). The pulmonary parenchyma appeared normal in opacity. Loss of the normal cardio-hepatic silhouette and reduced size of the caudal thoracic and abdominal air sacs were evident on the ventrodorsal projection. A space-occupying mass, located at the cranial aspect of kidneys, was visible in the lateral projection.
An ultrasonographic examination was also performed using a cranioventral approach caudal to the xiphoid of the sternum. Ultrasonographic images of the coelomic cavity were acquired using a GE Voluson 730 Pro (GE, Zipf, Austria) unit equipped with multifrequency (5-17 MHz) linear transducer and 4-dimensional (4D) linear transducer (6-18 MHz). Brightness mode 2-dimensional (2D) and 3-dimensional (3D) ultrasonography were performed to identify the origin of the mass with midline approach. Ultrasonographic images showed a generalized increased echogenicity of the liver and a mass with capsulated structure just dorsal to the liver. The well-defined mass appeared as a large, rounded, mixed echogenicity, inhomogeneous hyperechoic foci.
Ultrasound distinguished the mass from the liver and revealed high vascularity of the mass (with the use of the Doppler technique) and a moderate increase in echogenicity of the liver.
Three-dimensional ultrasonographic histogram analysis of the mass was performed with 4D View software (GE Healthcare, Zipf, Austria), and the mean gray index, vascularization index, flow index, and vascularization flow index were calculated as 28.44, 2.40%, 43.07, and 1.03, respectively. These were compared with liver indices, which were 23.78, 23.27%, 46.69, and 10.86, respectively. Three dimensional evaluation of the mass determined the approximate size to be 2.46 [cm.sup.3] (Figs 2 and 3).
The owner refused exploratory surgery and biopsy, and conservative therapy was provided, including subcutaneous rehydration with Ringer's solution and intramuscular vitamin B complex administration.
The bird died 3 days after presentation. At postmortem examination, severe hepatomegaly and a large soft tissue mass were revealed in the coelomic cavity. The mass was assumed to be an ovarian tumor with some degree of invasion to adjacent intestinal serosa. The liver was enlarged, gold-brown, and friable. Collected liver tissue and the suspected ovarian mass were fixed in 10% buffered formalin, paraffin embedded, sectioned, and stained with hematoxylin and eosin stain using a routine method for light microscopic examination. Microscopic examination of the mass revealed a lobular/acinar appearance in low magnification. The lobules had a regular distribution pattern in some areas, but variable arrangement in some other areas made them irregular. Bundles of smooth muscle and interlobular fibroplasia were seen. Almost no normal ovarian tissue was observed. Glandular lobules comprised mostly cuboidal cells with large pleomorphic nuclei. Variable, dominantly large nucleoli, along with a few mitotic figures, were seen. Amorphous and sometimes vacuolar eosinophilic materials were seen in some lobules. In some areas of the sections, instead of a well-organized lobular appearance, the neoplastic cells were aggregated in cords or with no regular patterns (Fig 4). Congestion and hyperemia of sinusoids and portal vein, mild to moderate diffuse fatty degeneration of hepatocytes, mild Kupffer cell proliferation, and mild bile duct hyperplasia were the nonspecific lesions seen in the liver.
The common mynah is a tropical and subtropical Asian bird endemic in Iran, particularly in southern parts of the country. This species has been introduced to many regions of the world. (1) Nowadays the common mynah is a popular pet bird in Iran. Although neoplasia is common in pet birds, (2) it has rarely been reported in common mynahs. Ovarian adenocarcinoma was reported in mature domestic fowl, (3) a domestic turkey, (4) budgerigars (Me/opsittacus undulatus), (5,6) and a greater flamingo (Phoenicopterus ruber roseus) ; however, to our knowledge, ovarian adenocarcinoma has not been previously reported in common mynahs.
Tumors of the ovaries include granulosa cell tumors, ovarian carcinomas, dysgerminomas, arrhenoblastomas, and teratomas. Small tumors may have no associated clinical signs, whereas large tumors may cause abdominal enlargement and dyspnea (through compression of the air sacs). Dyspnea and coelomic enlargement in this case were the result of a large tumor. Egg retention and oviductal impaction are some associated complications. Granulosa cell tumors (and possibly other reproductive tract tumors) may be functional and cause increased plasma hormone levels, (8,9) but unfortunately, plasma hormone levels were not analyzed in this case. While hyperestrogenism due to ovarian tumors may lead to medullary bone development and polyostotic hyperostosis, these signs were not seen in this case. Because specific detection and identification of coelomic masses are usually difficult with plain radiography, other diagnostic imaging modalities (combined 2D and 3D ultrasonography and computed tomography scan) could be helpful tools to identify the presence of a tumor. However, the definitive nature of the space-occupying mass should finally be confirmed by endoscopic, surgical, or ultrasonographic-guided biopsy. In this case, a 3D histogram differentiated the liver from the mass.
Ovarian adenocarcinomas arise from the germinal epithelium and have a variety of morphologic appearances. The ovarian adenocarcinoma can be scaled by the degree of differentiation of the neoplastic tissue. (8) Intermediate differentiation was diagnosed in this case.
Tumor metastases to the liver and lung are considered to be a consequence of vascular invasion, and those in the pancreatic serosa are attributed to transcoelomic spread. Ascites was reported as a common sequela to an ovarian adenocarcinoma in a domestic fowl and was associated with the serosal infiltration of the mesentery and intestines by tumor metastases. (3) Hepatic metastases were not seen in this case. Although histopathologic evaluation of the lungs was not performed, no radiographic or gross changes were seen in the lungs in this case. Although herniation can be a complication when ovarian tumors are present, no sign of herniation was seen in this case despite the coelomic enlargement caused by the large tumor. (10)
In examining the urogenital tract of birds, transcutaneous ultrasonography has proven to be a simple and fast diagnostic tool in detecting neoplasms that cannot be diagnosed using common noninvasive methods (eg, radiography). (11) In ultrasonographic detection of ovarian neoplasms that are accompanied by massive enlargement of the ovary, the well-defined structures appear as large, rounded masses of mixed echogenicity and echotexture, as reported in the characteristics of this neoplasm. Determining the type of neoplasm based on ultrasonographic features may not be possible with available information (11); however, quantitative data may help to characterize the type of neoplasm based on the nature of the cells and the contents of the tissue.
Results of a meta-analysis by Kinkel et al, (12) showed that the combination of gray-scale sonographic evaluation and Doppler imaging is more accurate than either modality alone in evaluating human ovaries. Because laying hens are the only animals that develop spontaneous ovarian cancer similar to humans, 3D ultrasonography may be a useful tool for evaluating ovarian tumors in both birds and humans.
In conclusion, 3D ultrasonography allows the sonographer to obtain better spatial perspective of the avian internal organs and is potentially superior to 2D sonography for evaluating irregularly shaped objects. Although further studies are needed to define their usefulness, the mean gray index, vascularization index, flow index, and vascularization flow index may be useful indices for characterizing ovarian tumors in birds.
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Yasamin Vali, DVM, Mohammad Molazem, DVM, DVSc, and Seyed Ahmad Madani, DVM, DVSc
From the Department of Surgery and Radiology. Faculty of Veterinary Medicine (Vali, Molazem) and the Department of Avian Diseases (Madani). Faculty of Veterinary Medicine, University of Tehran, Azadi Street. PO Box 14155-6453, Tehran, Iran.
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|Title Annotation:||Clinical Report|
|Author:||Vali, Yasamin; Molazem, Mohammad; Madani, Seyed Ahmad|
|Publication:||Journal of Avian Medicine and Surgery|
|Article Type:||Clinical report|
|Date:||Jun 1, 2015|
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