Preputial lymphangioma in a stallion: First report.

This short communication describes a case of a 30-year-old stallion with a mass on the base of the penis causing paraphimosis. The patient was submitted to anti-inflammatory and diuretic therapy with no signs of improvement, so 16 days after the lesion was detected, the animal was euthanized. Necropsy was performed, and histopathological assessment of the lesion was conducted. The mass was composed primarily of channels and cavernous structures, lined by elongated cells of vascular origin, located in the preputium. The lesion was diagnosed as a preputial lymphangioma. To the authors' best knowledge, the anatomical location of this neoplasm (which is rare in veterinary medicine) has not been previously reported.

Lymphangiomatosis of the systemic skin in an old dog.

A 13-year-old, neutered male miniature dachshund was presented with a one-month history of bilateral symmetrical swelling in the pinnae and carpal, cubital and tarsal joints, and swelling in the tail. The lesions were histopathologically characterized by multiple dilated lymphatic vessels lined by a single attenuated layer of endothelial cells. The subcutis was predominantly involved. A number of spindle-shaped cells lining the irregular vessels were observed. Morphological atypia was not evident in these cells. Immunohistochemical analyses revealed that the proliferating endothelial cells were positive for factor VIII-related antigen and CD31. Based on the clinical presentation and histopathological features, the dog was diagnosed with lymphangiomatosis. Treatment with anti-inflammatory prednisolone improved the symptoms.

Identification of equine cutaneous lymphangioma by application of a lymphatic endothelial cell marker.

An adult horse was presented with a mass located within the dermis and subcutis of the right forelimb. At post-mortem examination there was a marked increase in thickness of the subcutis of the right forelimb extending from the fetlock to the pectoral muscles. Microscopically, the dermis and subcutis were diffusely infiltrated by endothelial-like cells forming irregular channels and cavernous spaces. Immunohistochemical examination revealed the endothelial-like cells to express vimentin, factor VIII-related antigen and PROX-1, confirming the identity of the tumour as a lymphangioma. Ultrastructural analysis showed that the cavernous spaces were lined by a discontinuous endothelium lacking any basement membrane.

Tonsillar lymphangiomatous polyp in an adult dog.

A female spayed cocker spaniel dog, aged 8 years, developed a large, smooth pedunculated mass arising from the right palatine tonsil. Histology revealed that the mass was composed of many, variably dilated, thin-walled lymphatic channels filled with pale eosinophilic fluid lacking red blood cells and embedded in a dense, fibrovascular stroma. The dilated lymphatic channels were lined by a single layer of flattened, discontinuous endothelium with scattered intraluminal valves. Periodic acid-Schiff staining highlighted the discontinuous basement membrane and immunohistochemistry revealed strong cell membrane and cytoplasmic immunoreactivity for CD31 and von Willebrand factor, respectively. The clinical and histological findings were consistent with a tonsillar lymphangiomatous polyp - an uncommon, benign tumour of the tonsil in man that has previously been unrecognized in veterinary medicine.

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.

Canine vascular neoplasia--histologic classification and inmunohistochemical analysis of 221 tumours and tumour-like lesions.

A light microscopic evaluation of 221 canine vascular tumours and tumour-like lesions, supplemented by immunohistochemistry (von Willebrand Factor, CD31, vimentin), revealed a high degree of conformity with similar conditions in humans. Four main categories of tumours are reported, i.e. benign types: haemangiomas (n=127) and lymphangioma (n=1); tumour-like lesions: papillary endothelial hyperplasia (n=8) and vascular ectasias (n=2); neoplasms of intermediate malignancy: haemangioendotheliomas (n=27), and the obvious malignant form: angiosarcomas (n=57). Further classification showed that all subtypes had their human counterparts. Papillary endothelial hyperplasia and arteriovenous and venous haemangiomas are described for the first time in dogs. The combination of conventional histopathologic methods and immunohistochemistry was in many cases very useful diagnostically, the latter technique being in some cases indispensable for establishing a definite diagnosis. In general CD31 was the most useful marker for tumours originating from endothelial cells, especially for poorly differentiated haemangiosarcomas.

Canine vascular neoplasia--a population-based clinicopathologic study of 439 tumours and tumour-like lesions in 420 dogs.

This paper deals with a population-based material collected during the years 1990-1998, and comprises 439 tumours and tumour-like vascular processes from 420 dogs. Anatomic location, age, breed and gender are reported. A distinction is made between benign neoplasms, tumours of intermediate malignancy, and obvious malignant processes (angiosarcomas). Clinical behaviour, comprising recurrence and metastatic disposition, is included. Subclassification is done according to criteria used in human oncology. More than one half (242 of 439) occurred in the skin, and a great majority of skin processes (223 of 242) represented benign tumours or tumour-like lesions. The next most common site of summarised lesions was the spleen, with 110 cases, with only 17 processes in this organ being defined as benign. Splenic involvement was followed by the liver, with 13 out of 17 processes being angiosarcomas. Eleven of 12 heart tumours were angiosarcomas. A majority of skin haemangiomas was of the cavernous type (108 of 211), and more than one half (10 of 14) of the capillary haemangiomas were located on dorsal sites of the extremities. The mixed capillary/cavernous haemangiomas had a more diffuse distribution, although 20 of 31 were found in the skin of the hind limbs. Only one lymphangioma and one case of angiomatosis were observed. Most tumour-like proliferations were papillary endothelial hyperplasias. Recurrence occurred in 17 dogs, some of which had received a primary benign diagnosis. Primary metastases were observed in 63 animals, the majority in the spleen and heart. Dissemination involved a further 23 cases (22 had angiosarcoma). The male/female rate of benign tumours was 0.78, for tumour-like processes 1.83, intermediate malignant tumours 1.65, and angiosarcomas 1.60. With few exceptions, there was an overweight of all subclassified vascular lesions in animals more than 6 years of age.

Hepatic lymphangiomatosis in a young dog.

A 9-month-old intact male American cocker spaniel was referred because of hepatomegaly and ascites. Ultrasonographic evaluation of the liver revealed congestion and increased parenchymal echogenicity with focal and more hyperechoic nodules. Histopathology of the hepatic lesion revealed diffuse, ill-defined vascular proliferation. A single layer of endothelial cells, which showed signs of minimal cellular atypia, lined the irregular vessels. On immunohistochemistry, the proliferative endothelial cells lining the irregular vessels were positive for an antiserum to factor VIII related antigen. Based on these findings, the dog was diagnosed with hepatic lymphangiomatosis.

Invasive multiple lymphangiomas in a young dog.

An unusual case of multiple lymphangiomas with lymph node involvement is described. A seven-month-old, spayed female golden retriever was presented with a myriad of cystic masses in the inguinal and caudal mammary regions. She was diagnosed with congenital lymphangiomas (i.e., lymphatic hamartomas). As in human lymphangiomas, lymphatic endothelial cells expressing factor VIII-related antigen and smooth muscle were present in this case. A literature search did not identify similar characteristics in other reported canine lymphangiomas. The dog was treated surgically and had a recurrence. Following a second surgical intervention, she is now disease-free.

Lymphangioma in the metacarpal pad of a dog.

A five-year-old English springer spaniel was presented with a three year history of metacarpal ulceration causing lameness. The lesion was initially thought to be caused by a foreign body, but subsequently diagnosed as lymphangioma. The dog was surgically treated with resection of the metacarpal pad and transposition of the second digital pad. A severe infection developed 11 days postoperatively but was managed with antibiotics and intensive wound therapy. The surgical technique was successful, considerable adaptation of the transposed pad occurred and the dog returned to full weightbearing on the leg. However, one year later another area of new ulceration developed on the dorsomedial aspect of the paw. This, too, was resected but recurred after a short time and the owner elected for euthanasia of the dog.

Primary vascular neoplasms of lymph nodes in the dog.

Primary vascular neoplasms of lymph nodes are rare, and appear not to have previously been reported in domestic animals. This report describes hemangiomas and a lymphangioma in lymph nodes of aged Beagle dogs. Eight hemangiomas (4.8%) and one lymphangioma were present in 165 examined popliteal lymph nodes, and one hemangioma occurred in a hepatic lymph node. The hemangiomas were cavernous and benign.

Concurrent lymphangioma, immune-mediated thrombocytopenia, and von Willebrand's disease in a dog.

Lymphangioma, immune-mediated thrombocytopenia (IMT), and von Willebrand's disease (vWD) were diagnosed by histology, hematology, and a coagulation profile in a 14-month-old, female dachshund. Clinical and laboratory findings included ecchymotic inguinolabial swelling, thrombocytopenia, positive platelet factor-3 assay, prolonged buccal mucosal bleeding time, and subnormal von Willebrand factor antigen concentration and factor VIII activity. The IMT resolved with immunosuppressive glucocorticoid therapy. Histologic examination identified lymphangioma which was too extensive for surgical excision. The history and the clinical and laboratory findings were consistent with congenital vWD, although acquired vWD secondary to lymphangioma could not be ruled out.

Multiple hepatic cavernous lymphangioma in an aged male cat.

A 10-year-old male Domestic Longhair cat with weight loss, enlarged left testicle, icterus and mild liver enlargement showed, at necropsy, two white, raised, firm, circumscribed masses in the liver and striking enlargement of the left testicle. The histological features of the liver masses were consistent with lymphangioma. Severe, diffuse, coalescing to multifocal, subacute, necrotizing orchitis of the left testicle also was diagnosed. A literature review and examination of the epidemiology of lymphangioma in small domestic animals demonstrated the rarity of this tumour in cats.