Multiple hepatic peribiliary cysts in a young pig

Histopathologic features of hepatic peribiliary cysts were described in a young slaughtered pig. The animal was an apparently healthy 6-month-old pig of mixed breed. Macroscopically, all lobes of the liver contained numerous cysts of varying size containing serous fluid in all lobes. Histopathologically, the cysts were located mainly around the large bile duct and in the connective tissue of the portal tracts. Within serial sections, these cysts were assumed to be solitary or multilocular, but they were separated from the bile duct. The cysts were lined by a single layer of columnar, cuboidal, and flattened epithelial cells. Occasionally, goblet cells were observed. The epithelial cells were stained with periodic acid-Schiff/alcian blue and high-iron diamine/alcian blue, indicating the presence of neutral mucin, sialomucin, and sulfomucin. Grimalius' method revealed the presence of endocrine cells in the lining epithelium. There was no bile pigment in the cysts by the Hall method.     

Papillary renal adenoma of distal nephron differentiation in a horse

A 20-year-old thoroughbred mare had a mass in the right kidney. The mass was encapsulated with fibrous capsule and composed of variably-sized papillary projections lined by a single layer of flattened to cuboidal neoplastic epithelial cells with no cytological and nuclear atypia. Immunohistochemically, the neoplastic cells were broadly positive for cytokeratin AE1/AE3 and granular staining for alpha-1-antitrypsin was focally detected; this immunohistochemical property was similar to that of the normal distal nephron. From these results, this case was diagnosed as papillary renal adenoma of distal nephron differentiation.     

A morphological study of simple testicular cysts in the ostrich (Struthio camelus)

Simple testicular cysts are rare in mammals and of unknown aetiology, but dietary conditions have been implicated in this phenomenon in poultry. This study characterises the structural features of simple intratesticular cysts in the ostrich. Seven testes from a total of 15 sexually mature ostriches slaughtered during the breeding season were used. The testes contained multifocal, fluid-filled, unilocular cysts which were lined by a simple squamous or low cuboidal epithelium and surrounded by a thick layer of fibrous connective tissue. The cysts developed within seminiferous tubules and displayed morphological features similar to those reported in man and domestic poultry. The testis parenchyma revealed several foci composed of intermingled normal seminiferous tubules and variably sized intratesticular cysts. The atrophic tubules lay within a mass of hyperplastic, fibroblastic intertubular connective tissue in the proximity of large cysts and their formation appeared to result from hydrostatic pressure exerted by cysts. Morphological evidence supports a continuous process of cyst formation in the affected testis and a concomitant progressive loss of atrophic seminiferous tubules. A pathogenetic scenario of cyst formation and the effect of simple cysts on testicular histology has been proposed. Although the course of this phenomenon remains unknown, its impact on the fertility of this economically important bird deserves closer scrutiny.     

Bilateral Lymphangiomatous Testicular Lesions in a Lamb

Bilateral testicular enlargement was recognized in a young lamb; both gonads were largely replaced by a mass composed of multiple cystic spaces. Positive immunohistochemical staining for factor VIII-related protein indicated that the cysts were lined by endothelial cells. The precise nature and origin of the lesions is unclear; they might represent hamartomas or benign tumours or may be a result of lymphatic obstruction.     

Medullary sponge kidney in a 10-year-old Shih Tzu dog

Medullary sponge kidney was diagnosed in a 10-year-old male Shih Tzu dog with a long history of hyposthenuria, but with no other findings indicating renal failure or hormonal aberration. At the dog's death from heart failure, an autopsy was performed. On gross morphology, bilateral kidneys were normal size and had many cysts ranging from the corticomedullary junction to renal papillae. Histopathologic findings showed that almost all of the cysts were lined by monolayered or multilayered and columnar or cuboidal epithelium with chilium similar to epididymis. Immunohistochemically, all of these cells were strongly positive for AE1/AE3 and negative for vimentin. Many of these cells were positive for cytokeratin 7 (CK7), and only a few cells were positive for desmin. The results of staining are the same as those for epithelium of the collecting duct of normal canine kidney. This is the first report of this pathologic entity in the canine kidney.     

Intrahepatic splenosis in a dog

A 10-year-old castrated male Standard Poodle presented with an acute onset of lethargy and abdominal pain. The animal had a history of traumatic splenic rupture requiring splenectomy 5 years previously. Surgical exploration revealed multiple cystic red nodules involving all liver lobes, several of which were submitted for histopathology. Microscopically, the cystic nodules were dilated bile ducts and lymphatics surrounded by ectopic splenic tissue. A diagnosis of intrahepatic splenosis was made.     

Possible parachordoma in a dog

Abstract

CASE HISTORY: A 15-mm diameter mass developed in the S/C tissue overlying the right lateral gluteal muscle of a 6½-year-old female Flat-coated Retriever.

PATHOLOGICAL FINDINGS: Cytological preparations following aspiration of the mass were highly cellular and consisted of a population of large polygonal cells containing single to multiple nuclei, large prominent nucleoli, and intracytoplasmic vacuoles. Histologically, the neoplasm consisted of similar large cells surrounded by thick fibrous connective tissue trabeculae. The large polygonal cells reacted positively with antibodies against vimentin, low- and high-molecular-weight variants of cytokeratin (AE1/AE3), but not with antibodies to desmin or glial fibrillary acidic protein (GFAP).

DIAGNOSIS: The clinical, gross, histological and immunohistochemical findings are similar to those reported for parachordomas in humans. Neither recurrence nor metastases were noted 18 months after surgical excision of the mass.

CLINICAL RELEVANCE: This is the first reported case of a possible parachordoma in a dog, a benign tumour with cytological features of malignancy.     

Glomus tumor of the liver in a cow

An 11-year-old Holstein-Friesian cow exhibited anorexia and jaundice. A large mass was found in the liver during necropsy. Macroscopically, the mass was composed of dark red multilobular tissue and a centrally located abscess, which was connected to the hepatic duct. Histologically, the mass consisted of proliferation of small neoplastic cells and was demarcated from the hepatic parenchyma by a thick region of granulation tissue. The neoplastic cells were predominantly arranged in solid sheets, but they also formed blood-filled cancellous structures, and proliferating foci were seen around blood vessels. Periodic acid-Schiff reaction demonstrated that a fine basement membrane-like structure surrounded the neoplastic cells. Immunohistochemically, the neoplastic cells were positive for vimentin and alpha smooth muscle actin and negative for cytokeratin, factor VIII-related antigen, chromogranin and desmin. Based on its histopathological features, the hepatic neoplasm was diagnosed as a primary glomus tumor. This is the first report about a primary glomus tumor of the liver in a cow.     

猪肝棘球蚴超微结构和棘球蚴病病理形态学观察

对97例猪肝棘球蚴进行了系统的病理形态学观察,同时对其中3例作了扫描和透射电镜观察。病理学检查,均为单房型棘球蚴;采取囊液离心作头节检查,仅少部分有原头蚴。棘球蚴囊壁分为两层,内层(或胚层)较薄,伊红着染,外层为较厚的角质层,伊红淡染,呈无构造板层状结构。两层内无血管。PAS反应均为阳性。虫体周围常有变态反应性炎,形成寄生虫性肉穿肿,为本病的特征性病变。陈旧性肉芽肿中心无血管。肝组织是慢性间质性炎或肝硬化。透射电镜观察,胚层有很多生发层细胞呈指状突起的囊腔,其内有大量糖原颗粒和电子密度高的类核结构。胚层向角质层释放小颗粒样物质,角质层呈纤维网状。扫描电镜观察,胚层及内含物有生发囊、子囊和无机盐。角质层断面呈纤维网状,其外面有排列整齐的低柱状突起,形成有规则的皱褶,形如脑回状,表面密布较长的微绒毛。     

Multiple cystic intestinal duplications in a cat

A 7-year-old, female European shorthair cat with a history of recurrent vomiting had a 2-cm cystic mass in the midjejunum. Cross-sectioning and histology revealed 3 separate cystic structures in the muscular layer, in addition to a regularly structured intestinal lumen. One cyst had a 3-layered wall consisting of a dysplastic mucosa, a regularly structured submucosa, and partly double-layered muscularis that sporadically contained neurons resembling a myenteric plexus. The remaining 2 cysts had similar structures except for granulation tissue lining the lumen. The lesion was diagnosed as multiple cystic duplications in the midjejunum, which is unknown to the veterinary literature to date.     

Observations on the Fine Structure of the Liver in the Camel (Camelus dromedarius)

The structure of macroscopically inconspicuous livers in 23 adult camels (Camelus dromedarius) was studied by light and transmission electron microscopy. A well-developed connective tissue characterizes the camel liver. Thick trabeculae divide the liver parenchyma into lobules. Portal tracts and central veins are surrounded by a variable amount of fibrous tissue. In the perisinusoidal space (DISSE), collagen fibres form a dense three-dimensional network around the sinusoids. A mild to moderate fatty infiltration is present in hepatocytes of all animals. In the epithelial cells of the bile ducts, small to medium sized lipid inclusions are a common feature. The ultrastructure of hepatocytes in the camel liver corresponds to that of other domestic mammalian species. The endothelial cells lining the sinusoids show a multiple fenestration and are surrounded by a discontinuous basal lamina. Fat-storing cells are numerous and contain lipid droplets varying in size, number and electron density from one cell to another.     

Back-scattered electron imaging of a non-vertebral case of hypervitaminosis A in a cat.

We describe a clinical case of hypervitaminosis A in a cat. The main lesions were bony fusions of both the hip and stifle joints, without spinal involvement. A post-mortem study using back-scattered scanning electron microscopy (BEI-SEM) revealed that exostoses had formed around the joints without articular surface involvement. The more recently formed areas of bony proliferation were composed mainly of chondroid tissue surrounded by different degrees of woven bone. As the bony reaction occurred, remodelling of the trabeculae was observed which lead to progressive substitution of chondroid tissue by woven bone surrounded by apposition of lamellar bone. No traces of calcified cartilage were observed in any of the bone sections evaluated.     

Squamous cell carcinoma with sarcomatous stroma in the nasal cavity of a dog

This is a report of an unusual squamous cell carcinoma in the nasal cavity of a dog. A 13-year-old Golden Retriever was presented with a unilateral nasal and ocular discharge. Although a nasal tumour was suspected, initial diagnostic investigations were unrewarding, and, with worsening clinical signs, the dog was euthanatized. Necropsy examination confirmed the presence of a nasal tumour that was composed histologically of both a well-differentiated squamous cell carcinoma component blending with a predominant spindle cell component. Immunohistochemical staining with anti-human keratin/cytokeratin (AE1/AE3, CAM 5.2 and broad spectrum cytokeratin), Vimentin, Desmin, smooth muscle actin and S-100 protein supported a diagnosis of a squamous cell carcinoma with (pseudo) sarcomatous stroma.     

Hemangiosarcoma with widespread metastasis that originated on the metatarsal pad of a Java sparrow (Padda oryzivora)

A five-year-old male Java sparrow (Padda oryzivora) was examined because of the appearance of a purple spot approximately 1 mm in diameter on the right metatarsal pad. Seven months later, the spot spread to the entire right leg, and the bird died. At necropsy, multiple neoplastic masses on the right leg reached up to the pelvic cavity. There was one similar mass on the right kidney and multiple red spots on the liver. Histopathological examination revealed that neoplastic cells proliferated solidly or formed abundant irregular blood vessels. Watanabe silver staining revealed that neoplastic cells were surrounded by argentophil fibers. Immunohistochemically, the neoplastic cells were positive for anti-human von Willebrand factor antibodies. This is the first report of hemangiosarcoma in a finch.     

Polypoid eosinophilic cystitis with pseudosarcomatous proliferative tissue in a dog

A dog presented with hematuria, and two small polypoid masses were detected in the urinary bladder. Histopathologically, the masses were located in the mucosal or submucosal layer. That tissue consisted of a random proliferation of spindle-shaped, round and pleomorphic cells with single or multiple large atypical nuclei and abundant cytoplasm, and eosinophil infiltration. These large cells were confirmed by immunohistochemical staining as fibroblasts, myofibroblasts and macrophages. Mitotic figure was rarely seen. These masses were diagnosed as eosinophilic polypoid cystitis with pseudosarcomatous proliferative tissue, since they consisted of a wide variety of cells and showed low growth activity.     

Immunohistochemical evaluation of canine ovarian cysts

To clarify the immunohistochemical characteristics of canine ovarian cysts, 109 canine ovarian cysts (57 cysts of subsurface epithelial structures: SES, 26 graafian follicle cysts, 12 cystic rete ovarii and 14 cysts difficult to classify morphologically) were examined regarding their lining cells immunohistochemically using antibodies against placental alkaline phosphatase (PLAP), S100, inhibin alpha, desmin and AE1/AE3. Both cysts of SES and cystic rete ovarii had a positive immunoreaction to desmin and AE1/AE3, whereas all cysts all but graafian follicle cysts were negative for inhibin alpha. PLAP-positive immunoreaction was observed only in cysts of SES. Graafian follicle cysts had a positive immunoreaction to inhibin alpha, but were negative for PLAP, desmin and AE1/AE3. Fourteen cysts were difficult to classify morphologically because these cysts had single-squamous lining cells and lacked other morphological characteristics. However, these unclassified cysts were immunohistochemically divided into two groups, including positive and negative cysts, by the reactivity of PLAP. The PLAP-positive cysts were considered large cysts of SES. These results suggest that PLAP was a useful marker for classification of cysts of SES, although cysts originating from SES are not always positive for this antigen.     

Hepatic alveolar echinococcosis in cynomolgus monkeys (Macaca fascicularis)

Alveolar echinococcosis was diagnosed in 12 cynomolgus monkeys (Macaca fascicularis) at postmortem examination within a period of 6 years. Besides consistent involvement of the liver, parasitic lesions were also present in mesenteric lymph nodes, pancreas, lung, and kidney. In the liver, various patterns of host's responses to parasitic tissue could be distinguished. Infiltration of macrophages, often multinucleated, around usually intact metacestodes was the main feature of one pattern. A second pattern was characterized by the presence of abundant, normally degenerate granulocytes in addition to macrophages surrounding collapsed laminated structures. Finally and as a third pattern, some cysts were surrounded by marked collagen deposition, which was usually not a significant feature of the other foci. Parasitic cysts with protoscolices were observed in foci with the first and third pattern but not in the second one. The simultaneous occurrence of all three patterns was observed in most animals. Type AA amyloid was identified either in the space of Dissé, macrophages or blood vessel walls in nine animals using immunohistochemistry. Identity of parasitic structures such as metacestodes of Echinococcus multilocularis was confirmed immunohistochemically. All animals that could be tested serologically (7/12) had detectable antibodies against the E. multilocularis-specific Em2 antigen. Liver lesions of six animals were additionally analyzed by polymerase chain reaction, yielding the amplification of a specific E. multilocularis DNA fragment in each case.     

Clinical and Pathological Findings of a Sac‐like Formation in the Tunica Vaginalis of a Nelore (Bos indicus) Bull

A seven‐month‐old purebred Nelore calf was diagnosed with a bilateral finger‐shaped swelling although more prominent at the left side of the scrotum, located longitudinal and parallel to epididymis corpus. The finding was present from 7 months of age up to castration (performed at 25 months of age). Scrotal circumference, testicular and epididymis consistency and symmetry as well as seminal quality were normal during the follow‐up period. The ultrasonographic appearance of the scrotal wall, pampiniform plexus, gonad and epididymis was normal. However, an anechoic region surrounded by a wall forming a sac‐like structure with a blind end at its dorsal pole was seen on the swelling area. The examination of fluid aspirated from the saccular contents revealed the presence of mononuclear cells mainly from lymphocytic and histiocytic type as well as some loosing degenerated mesothelial cells. Gross examination at castration revealed a blind sac‐like appendix derived from an evagination in the parietal layer of the tunica vaginalis. The structure of approximately 5.0 cm in length extended from the dorsal edge of the epididymis cauda. No adherences with surrounded tissues were observed. Histopathology of the sac wall showed a smooth inner surface composed by scarce mesothelial cells forming in some areas papillary‐like projections protruding to the vaginal cavity. Underneath, a thick layer of fibrous tissue mixed with collagen fibres and mononuclear inflammatory cells were seen. The potential consequences of this saccular formation at an older age in a bull are unknown.