Incidentally detected retroperitoneal paraganglioma in a 10-year-old French bulldog

This article reports a case of a 10-year-old French bulldog initially seen for reluctance to move and episodes of pain. A magnetic resonance imaging study was undertaken in order to rule out a herniated disc. A large, retroperitoneal mass was visualized and cytological analysis suggested a neoplastic proliferation. The mass appeared to compress the caudal vena cava when viewed by abdominal CT scan. The mass was surgically removed. A nephrectomy was also carried out and aortic bleeding identified after dissection of adhesions. Despite these complications, the dog did well after the procedures. Postoperative checkups were normal. Histological and immunohistochemical analyses of the mass were compatible with a retroperitoneal paraganglioma. Key clinical message: This type of tumor is poorly described in the veterinary literature. As the behavior of this tumor type is not yet fully understood, each new description adds to our knowledge and should help in diagnosing and treating it more effectively in the future.

Laparoscopic resection of retroperitoneal paraganglioma close to caudal vena cava in a dog

OBJECTIVE

To report laparoscopic resection of retroperitoneal paraganglioma close to the caudal vena cava in a dog.

STUDY DESIGN

Case report.

ANIMAL

Twelve-year-old, neutered male Jack Russell terrier.

METHODS

The dog had undergone three previous cystotomies for bladder stones. On follow-up ultrasonographic evaluation, a 14-mm × 17-mm tumour was incidentally detected in the dorsal midline of the caudal abdomen. The dog underwent computed tomography (CT) imaging and ultrasound-guided fine needle aspiration of the tumour under general anaesthesia. CT imaging showed that the tumour was close to the caudal vena cava. There was no evidence of metastasis. Neuroendocrine tumour was suspected on cytologic examination. Based on these findings, laparoscopic tumour resection was performed using a vessel-sealing device. The operation time was 136 minutes.

RESULTS

The dog was stable after recovery from anaesthesia and discharged to home the next day. Histopathological diagnosis of the tumour was a paraganglioma. The dog remained without clinical evidence of recurrent tumour or metastasis for 670 days after the surgery.

CONCLUSION

Retroperitoneal paraganglioma in dogs is uncommon, but it is one of the differential diagnoses of a retroperitoneal tumour. Laparoscopic resection of a retroperitoneal paraganglioma was successfully performed in the dog. Laparoscopic resection conferred the advantages over open surgery of being minimally invasive, providing better visualization of the surgical field through pneumoperitoneum and semisternal patient recumbency, and allowing for magnification of the operative field, which facilitated the ease and safety of the procedure.

Subcutaneous ureteral bypass for treatment of bilateral ureteral obstruction in a cat with retroperitoneal paraganglioma

CASE DESCRIPTION A 7-year-old female domestic shorthair cat was referred for evaluation of azotemia and unilateral hydronephrosis. CLINICAL FINDINGS Abdominal ultrasonography revealed right-sided hydronephrosis and dilation of the proximal aspect of the ureter; the left kidney was small with irregular margins. A highly vascular, irregular retroperitoneal mass, not clearly associated with the ureteral obstruction, was also visualized. Surgical exploration confirmed a retroperitoneal mass involving the caudal mesenteric artery and both ureters, with hydroureter on the right side. TREATMENT AND OUTCOME A subcutaneous ureteral bypass (SUB) device was surgically implanted to treat right ureteral obstruction, and the mass was biopsied. Shortly after surgery, progressive azotemia and hyperkalemia were detected; ultrasonographic examination revealed left-sided hydronephrosis and hydroureter, which was suspected secondary to inflammation of the mass causing a left-sided ureteral obstruction. A second surgery was performed to place an SUB device for the left kidney and remove the retroperitoneal mass; both ureters were ligated at the mid- and distal aspects and then transected and removed with the mass. A neuroendocrine paraganglioma was identified by histopathologic evaluation of the mass. Hydronephrosis improved (right kidney) or resolved (left kidney) after surgery, and azotemia improved. Chemotherapeutic intervention was declined. Markers of renal function were static during the 14-month follow-up period. At the last follow-up evaluation, the patient was reportedly doing well, and both SUB devices were patent. CLINICAL RELEVANCE This was the first report of retroperitoneal paraganglioma in a domestic cat causing bilateral ureteral obstruction. Bilateral SUB device placement enabled en bloc mass resection and provided long-term relief of ureteral obstruction.

Retroperitoneal hemangiosarcoma in a common carp Cyprinus carpio: a case report

A 7.5 kg common carp Cyprinus carpio presented with prominent localized swelling in the caudal right coelomic area, identified by ultrasound as a fluid filled mass. Fine needle aspirate (FNA) and culture results suggested a sterile seroma. Centesis removed 290 ml of serosanguinous fluid that returned within days. Recheck ultrasonography revealed a solid component within the cavity. Radiography demonstrated irregular lysis and misalignment of vertebrae adjacent to the mass, most suggestive of bacterial osteitis or neoplasia. Treatment with antibiotics followed for 2 mo but failed to resolve the lesion. Repeated radiography and ultrasonography showed progressive enlargement of the mass, with vertebral lysis and invasion characteristic of neoplasia. Ultrasound-guided FNA of the solid component of the mass was non-diagnostic. Euthanasia was elected due to the poor clinical response and primary differential of neoplasia. Post-mortem MRI and CT confirmed a retroperitoneal soft tissue mass, partially surrounded by a fluid-filled cavity, causing vertebral lysis and infiltration of the spinal canal. Expansion of the mass caused severe muscle loss and an associated elevation in creatine kinase (>120000 U l-1). Necropsy results corroborated the MRI and CT findings, revealing a retroperitoneal, multilobular, red and tan mass causing dorsal displacement of the vertebral column, with vertebral lysis, pathologic fracture and invasion of the spinal canal. Histopathologic examination revealed a locally aggressive neoplasm exhibiting multiple patterns of growth, including endothelial lined vascular channels and solid areas formed by more pleomorphic polygonal and spindle cells, consistent with hemangiosarcoma.

Retroperitoneal teratoma in a skunk (Mephitis mephitis)

A 4-yr-old striped skunk (Mephitis mephitis) developed an 11- x 7- x 7-cm retroperitoneal mass caudal to the left kidney. The mass was surgically excised and, on the basis of histology and immunohistochemistry, diagnosed as a benign teratoma. Six months later, a second histologically similar neoplasm was excised from the same location and was considered to represent local tumor recurrence. The skunk died 16 mo later without recurrence. Complete excision of the tumor appeared curative in this case and supported the benign diagnosis. An extragonadal teratoma should be considered as a differential diagnosis for an abdominal mass in a skunk.

Retroperitoneal sarcomas in dogs: 14 cases (1992–2002)

OBJECTIVE

To describe the clinical features, surgical and histologic findings, biological behavior, and outcome of dogs with retroperitoneal sarcomas.

DESIGN

Retrospective study.

ANIMALS

14 dogs.

PROCEDURES

Medical and pathology records from 1992 to 2002 of dogs with tumors originating in the retroperitoneal space were reviewed. Dogs with retroperitoneal tumors originating from the adrenal glands, kidneys, or ureters were excluded. Inclusion criteria included observation of a tumor arising from the retroperitoneal space during exploratory surgery or necropsy and histologic confirmation of tumor type. Details of clinical signs, diagnostic findings, surgical management, and outcome were determined from medical records and telephone interviews with veterinarians and owners.

RESULTS

Retroperitoneal sarcoma was diagnosed in 14 dogs, 2 at necropsy and 12 during exploratory surgery. Hemangiosarcoma was the most common histologic diagnosis. Seven dogs had regional extension of the sarcoma into adjacent organs, and 4 dogs had metastatic disease. Grossly complete resection was possible in 6 dogs. Cytoreductive surgery or incisional biopsy was performed in the remaining dogs. Two dogs were treated with palliative radiation therapy (1 intraoperatively and 1 postoperatively). Three dogs received adjunctive chemotherapy, although none completed the targeted course because of development of local recurrence or metastatic disease. Local recurrence was reported in 2 of 12 dogs and metastasis in 10 of 14 dogs. Thirteen dogs died or were euthanatized as a result of the retroperitoneal sarcoma; 1 dog was alive and disease-free 410 days after surgery. Median survival time was 37.5 days.

CONCLUSIONS AND CLINICAL RELEVANCE

In dogs, retroperitoneal sarcomas are aggressive tumors with a high rate of local recurrence and metastasis, and a poor survival time.

Analysis of 4.3 kilobases of divergent locus B of macaque retroperitoneal fibromatosis-associated herpesvirus reveals a close similarity in gene sequence and genome organization to Kaposi's sarcoma-associated herpesvirus

We previously identified retroperitoneal fibromatosis-associated herpesvirus (RFHV) as a simian homolog of Kaposi's sarcoma-associated herpesvirus (KSHV) in a fibroproliferative malignancy of macaques that has similarities to Kaposi's sarcoma. In this report, we cloned 4.3 kb of divergent locus B (DL-B) flanking the DNA polymerase gene from two variants of RFHV from different species of macaque with a consensus degenerate hybrid oligonucleotide primer approach. Within the DL-B region of RFHV, viral homologs of the cellular interleukin-6, dihydrofolate reductase, and thymidylate synthase genes were identified, along with a homolog of the gammaherpesvirus open reading frame (ORF) 10. In addition, a homolog of the KSHV ORF K3, the modulator of immune recognition-1, was identified. Our data show a close similarity in sequence conservation, gene content, and genomic structure between RFHV and KSHV which strongly supports the grouping of these viral species within the same RV-1 rhadinovirus lineage and the hypothesis that RFHV is the macaque homolog of KSHV.

Hypercalcaemia associated with a retroperitoneal apocrine gland adenocarcinoma in a dog

A seven-year-old, entire female golden retriever was presented with a history of polyuria/polydipsia and progressive dysuria. Clinical examination, radiography and ultrasonography demonstrated urinary retention due to a large soft tissue mass in the retroperitoneal space. Laboratory findings revealed paraneoplastic hypercalcaemia. Fine-needle aspiration cytology of the mass suggested an epithelial tumour, resembling an apocrine gland carcinoma of the anal sac. Following euthanasia and necropsy, the histopathological diagnosis of the retroperitoneal mass was apocrine gland adenocarcinoma. Despite ante- and postmortem examination, no perineal or anal sac tumour was found. The retroperitoneal tumour in this case could be a very large lymph node metastasis from an occult primary apocrine carcinoma of the anal sacs, or it could represent the first case of an ectopic apocrine gland carcinoma of the retroperitoneal space in a dog.

Malignant retroperitoneal paraganglial tumour in a cow

A large primary retroperitoneal sublumbar neoplasm was identified in an 11-year-old Holstein cow, with metastases to the lungs, kidneys and lymph nodes. The tumour cells proliferated in a characteristic endocrine pattern, were argyrophilic and positive for neuron-specific enolase, and had membrane-bounded intracytoplasmic granules. In addition, the cells were occasionally positive for cytokeratin and had desmosome-like intercellular junctions. The primary tumour mass was diagnosed as a malignant paraganglial tumour of the aortico-sympathetic ganglion (organ of Zuckerkandl), and was considered to contain primitive cells with epithelial differentiation.

Retroperitoneal extraskeletal mesenchymal chondrosarcoma in a dog

A young adult female Mastiff dog developed a large retroperitoneal mass, pleural effusion, and multiple pulmonary and pleural nodules. All masses were diagnosed as mesenchymal subtype chondrosarcomas, using histological and immunohistochemical criteria. Reports of canine extraskeletal mesenchymal chondrosarcomas (EMCs) are rare but involved animals less than 3 years of age in 60% of the cases. This is the first description of this type of tumor developing distant metastases. Evidence from this case and previous reports suggests that EMCs are associated with a poor prognosis.

Canine hemangiosarcoma treated with standard chemotherapy and minocycline

Standard treatments for canine hemangiosarcoma include surgery and chemotherapy with doxorubicin, but in spite of treatment most dogs with this disease die within 6 months of diagnosis. Tumor growth and metastasis are angiogenesis dependent. Antiangiogenic drugs such as minocycline may provide therapeutic benefits in cancer patients. The purpose of this prospective study was to evaluate the efficacy of chemotherapy with doxorubicin and minocycline, an antiangiogenic agent, in dogs with hemangiosarcoma. Eighteen dogs with histologically confirmed hemangiosarcoma of any stage were treated with doxorubicin, cyclophosphamide, and minocycline. Complete staging was performed before and during the treatment period to assess remission status and response to therapy. No statistically significant difference was found in survival between the dogs treated with chemotherapy and minocycline, and historical controls consisting of dogs that received chemotherapy alone. Postmortem examination revealed widespread metastasis, suggesting that minocycline is ineffective as a single antiangiogenic agent in canine hemangiosarcoma.

Ovarian and retroperitoneal teratomas in a dog

A 2-year-old female Labrador retriever was presented with anorexia and abdominal distention. Laparotomy revealed the presence of a 31-cm ovoid mass in the portion of the left ovary and an 11-cm round mass in the left retroperitoneal region. Both masses were surgically removed. Histopathological examination of the masses revealed a mixture of tissues characteristic of teratomas, such as multiple bronchial and intestinal cysts, hair follicles, sebaceous and apocrine sweat glands, and neuron tissue with intervening cartilage, bone and fat tissue. This paper appears to be the first report of primary retroperitoneal teratoma in the dog.

Identification of two homologs of the Kaposi's sarcoma-associated herpesvirus (human herpesvirus 8) in retroperitoneal fibromatosis of different macaque species

Simian retroperitoneal fibromatosis (RF) is a vascular fibroproliferative neoplasm which has many morphological and histological similarities to human Kaposi's sarcoma (KS). Like epidemic KS in AIDS patients, RF is highly associated with an immunodeficiency syndrome (simian acquired immunodeficiency syndrome [SAIDS]) caused by a retrovirus infection. Recently, a new gammaherpesvirus, called Kaposi's sarcoma-associated herpesvirus (KSHV) or human herpesvirus 8 (HHV8), has been identified in KS tumors, suggesting that KS has a viral etiology. Our previous experimental transmission studies and epidemiological data suggest that RF also has an infectious etiology. In order to determine whether a similar virus is also associated with RF, we have assayed for the presence of an unknown herpesvirus using degenerate PCR primers targeting the highly conserved DNA polymerase genes of the herpesvirus family. Here we provide DNA sequence evidence for two new herpesviruses closely related to KSHV from RF tissues of two macaque species, Macaca nemestrina and Macaca mulatta. Our data suggest that KSHV and the putative macaque herpesviruses define a new group within the subfamily Gammaherpesvirinae whose members are implicated in the pathogenesis of KS and KS-like neoplasms in different primate species.

Malignant retroperitoneal paraganglioma in a horse

A large primary retroperitoneal sublumbar neoplasm in a horse, with disseminated neoplastic foci in the brain, lung, kidney and spleen is described. The diagnosis was based on light microscopical studies and positive immunostaining for neuron-specific enolase. Because of the location of the primary tumour mass, the aortico-sympathetic ganglion (organ of Zukerkandl) is proposed as the origin.

Chordoma with osseous element in a F344 rat

Chordoma occurred in the sacrococcygeal region of the vertebral column of a 97-week old male control F344 rat. Macroscopically, it was a mass (20 mm in diameter) protruding into the retroperitoneum and the cut surface was white to dark-reddish and showed a gelatinous appearance. Histologically, the tumor was composed of physaliphorous and stellate cells growing in nests or cords and divided into lobules by a thin fibrous stroma. The tumor cells locally invaded adjacent tissues, but no metastasis to other organs was noted. Centrally, the tumor often had islands of bone that entrapped physaliphorous cells and the bone tissue consisted of well-differentiated osteocytes. Based on these findings, this tumor was diagnosed as chordoma with osseous element.

Caprine peripheral neuroblastomas: structural and ultrastructural features, intermediate filaments profile and neuro-endocrine characterization

In this report the morphological and immunohistochemical features with respect to intermediate filament proteins and the neuroendocrine nature of bilateral neuroblastomas possibly originating from the adrenal medulla in a goat kid are presented. Histologically, the tumours were composed of small, round, blue cells organized in highly cellular nests and sheets separated by fibrovascular septa. Isolated cells mimicking the morphological features of neurones were observed in both tumours. Ultrastructurally, dense-core neurosecretory granules, about 100 nm in diameter, and irregularly organized neurotubular networks were seen. The small tumour cells were only labelled by vimentin, while the neurone-like cells were labelled by both neurone-specific enolase and synaptophysin. The lack of staining of the tumour cells by the neurofilament proteins antiserum, which was also observed in a human neuroblastoma (used as positive control) has been previously reported and is probably the result of the tissue processing and/or the poor differentiation stage of the tumours. The vimentin labelling of tumour cells could be explained by the poor differentiation stage of the tumours, since vimentin is the only intermediate filament protein in presumptive neuroblasts, being replaced by neurofilament proteins in later stages of neurogenesis.

Pigmented villonodular synovitis and plasmacytoid lymphoma in a dog

A 4-year-old Labrador Retriever was examined because of progressive left hind limb lameness involving the stifle. A villous synovial mass was evacuated by synovectomy. Initially, the macroscopic and histopathologic features suggested a malignant fibrosarcomatous process; however, further histologic studies revealed lesions consistent with pigmented villonodular synovitis. Nine months later, the dog developed a large retroperitoneal tumor, with metastasis to the lungs and liver. The dog was then euthanatized. By histologic and electron microscopic examinations, the tumor was found to be a primitive plasmacytoid lymphoma.

Retroperitoneal fibromatosis and acquired immunodeficiency syndrome in macaques: clinical and immunologic studies

A simian acquired immunodeficiency syndrome (SAIDS) associated with retroperitoneal fibromatosis (RF) has been observed in several species of macaque at the Washington Regional Primate Research Center. Clinical signs were recurrent diarrhea, weight loss, mesenteric lymphadenopathy, and opportunistic infections. Most affected macaques in the later stages of illness showed marked immunodeficiency. Response of peripheral blood mononuclear cells to mitogens was impaired significantly. There was sharply depressed primary and secondary antibody response to the T-cell dependent antigen, bacteriophage phi X174. Affected monkeys did not switch from IgM to IgG antibody following a secondary immunization, as did normal macaques. Twenty-four (67%) of 36 affected animals with progressive RF or deteriorated stages of illness had hypoproteinemia and hypoalbuminemia. Quantitative serum immunoglobulins of 23 cases showed that eight (35%) had hypogammaglobulinemia, six (26%) had hypergammaglobulinemia, and the remainder (39%) were within the normal range. Opportunistic infections were predominantly bacterial pathogens. Type D retrovirus appeared to be closely associated with RF-affected macaques (12/12 or 100%). The case fatality rate (including animals sacrificed after prolonged illness) was 98%. The leading cause of death was due directly to RF lesions in 43%, to enterocolitis in 36%, septicemia in 12%, amyloidosis in 5%, and malignant lymphoma (2%). Clinical, immunologic and pathologic changes reveal an acquired immunodeficiency syndrome that has many similarities to human AIDS. SAIDS and RF may be a useful model for studying human AIDS.

Subcutaneous fibromatosis associated with an acquired immune deficiency syndrome in pig-tailed macaques

A spontaneous multifocal subcutaneous fibromatosis is described in 6 pig-tailed macaques (Macaca nemestrina) with simian acquired immune deficiency syndrome (simian AIDS). The lesions consisted of a proliferation of vascular fibrous tissue that was infiltrated by lymphocytes and plasma cells. One animal also had retroperitoneal fibromatosis, which has also been found in this colony of pig-tailed macaques. Progressive weight loss, diarrhea, lymphadenopathy, and neutropenia were seen. Peripheral lymph nodes were hyperplastic, and there was splenomegaly. Aggregates of lymphocytes were present in the bone marrow, kidneys, liver, and lungs. Type D retrovirus particles were found in three nodules by electron microscopy; intracytoplasmic type A and budding particles were identified in fibroblasts. In a setting of acquired immunodeficiency, these subcutaneous tumors in pig-tailed macaques present a striking analogy to Kaposi's sarcoma in human AIDS.

Characterization of exogenous type D retrovirus from a fibroma of a macaque with simian AIDS and fibromatosis

A novel type D retrovirus was isolated by cocultivation of explants of fibromatous tissue from a rhesus monkey (Macaca mulatta) with immunodeficiency and retroperitoneal fibromatosis. This type D virus, isolated from a macaque with simian acquired immunodeficiency syndrome (SAIDS-D/Washington), is exogenous and is partially related to the Mason-Pfizer and the langur monkey type D viruses. The SAiDS-D virus can be distinguished from all other primate retroviruses by antigenicity and molecular hybridization. Nucleic acid hybridization studies reveal that the origin of the SAIDS-D isolate may reside in Old World monkey (subfamily Colobinae) cellular DNA.

Cystic lymphangioma in a colt

A 6-month-old Morgan colt was examined because of preputial edema and multiple nodular masses in the left inguinal region. A tentative diagnosis of lymphatic hamartoma was made on the basis of initial biopsy findings. The prognosis for surgical excision was poor due to the progressive expansile growth of the tumor. Secondary infectious complications developed, and the colt was euthanatized at the owner's request. An abdominal and retroperitoneal mass was seen at postmortem examination. The mass was adherent to the left lumbar musculature, the craniodorsal aspect of the pelvic inlet, the midjejunum, the left testicle, and the left kidney. The mass extended through the left inguinal and femoral canals into the deep intermuscular fascia of the hindlimb. Histologic examination of the mass indicated that it was a cystic lymphangioma.

Lymphangioma in four dogs

Lymphangioma, a rare benign tumor of lymph vessels, was diagnosed in 4 dogs. The lesions were in the nasopharynx, retroperitoneum, axilla, and medial aspect of thigh. Treatment was either surgical excision or marsupialization.

Teratoma in a chicken (Gallus domesticus)

A large mass composed of multiple tissue elements was observed in the abdominal cavity of a chicken. The tumor mass was tridermic microscopically, and therefore classified as a teratoma.

Neuroblastoma in the dog

Two malignant canine tumours of peripheral neuronal tissue are described. A mediastinal neuroblastoma was found in a 15-mth-old Boston Terrier with dyspnoea. The tumour compressed adjacent lung and invaded the cervical spinal cord. A retroperitoneal ganglioneuroma was found in a 2-yr-old Labrador with posterior ataxia and atrophy of the muscles of the hind legs. This tumour surrounded adjacent adjacent soft tissues and invaded the overlying vertebrae.