Hypercalcemia associated with gastric pythiosis in a dog

A 20-month-old castrated male Labrador Retriever with a 3-month history of anorexia, weight loss, and vomiting was evaluated. Plasma biochemical abnormalities included marked hyperglobulinemia and hypercalcemia. Serum levels of parathyroid hormone, parathyroid hormone-related protein, 25-hydroxyvitamin D, and 1,25-dihydroxyvitamin D were either low or within reference intervals. Gastric wall thickening and abdominal lymphadenomegaly were observed with abdominal ultrasonography. Cytologic evaluation of a sample obtained via fine-needle aspiration of the gastric wall revealed pyogranulomatous inflammation and numerous poorly stained hyphae. Partial gastrectomy was performed, and a diagnosis of gastric pythiosis was made by immunohistochemical staining of infected gastric tissue, as well as by immunoblot serology. This case demonstrates that diagnostic samples for cytologic evaluation can be obtained by fine-needle aspiration of Pythium insidiosum-infected tissues and that a presumptive diagnosis can be made by examination of a Romanowsky-stained smear. Furthermore, pythiosis should be considered as a differential diagnosis for hypercalcemia, especially in young dogs with inflammatory lesions that have a granulomatous component. The mechanism for the hypercalcemia in this dog was not determined; however, calcium concentrations normalized after surgical resection of the gastric lesion.     

Hypercalcemia and high parathyroid hormone-related peptide concentration in a dog with a complex mammary carcinoma

A 10-year-old female Dachshund was presented with a history of mammary masses, slight lethargy, polyuria, and polydipsia. Physical examination findings included masses involving the first, second, and fourth mammary glands of the left side. The mandibular, axillary, and right popliteal lymph nodes were mildly enlarged. Serum chemistry results included hypercalcemia (13.9 mg/dL, reference interval 8.0-11.5 mg/dL). Although intact parathyroid hormone (PTH) concentration (1.05 pmol/L) was below the reference interval (2-13 pmol/L), PTH-related protein (PTHrP) concentration was markedly increased (9.40 pmol/L, reference value < 2 pmol/L). The masses were surgically removed, and the histopathologic diagnosis was complex mammary carcinoma. Three weeks after surgery, serum total calcium concentration had decreased to 10.5 mg/dL. Resolution of the hypercalcemia and clinical signs supported a diagnosis of humoral hypercalcemia of malignancy associated with mammary gland carcinoma.     

Successful use of prednisolone and radiation therapy in a dog with intracranial histiocytic sarcoma

The ideal treatment for intracranial histiocytic sarcoma (HS) remains unclear. Herein, we report a case of intracranial HS that was successfully treated using prednisolone and radiation therapy. The patient was a 9-year-old spayed female Pembroke Welsh Corgi that presented with epileptic seizures. Magnetic resonance imaging revealed a contrast-enhancing mass adjacent to the right piriform lobe. Prednisolone administration (1 mg/kg/day) decreased the lesion size. Additional palliative radiation therapy (total dose, 37 Gy) resulted in complete disappearance of the lesion. However, on day 164, the dog’s neurological signs deteriorated, and she was euthanized. Necropsy revealed an intracranial metastasis of HS via the cerebrospinal fluid without any extracranial metastasis. Nonetheless, combined prednisolone and radiation therapy might be effective in treating intracranial HS.     

Parathyroid hormone‐related protein‐induced hypercalcemia due to osteosarcoma in a cat

A 15‐year‐old castrated male mixed‐breed cat was presented with a history of sarcoma of the distal right hind limb. Biochemical analysis revealed increased concentrations of blood urea, creatinine, total calcium, ionized calcium, and parathyroid hormone‐related protein (PTHrP). The mass was removed surgically by amputation of the hind limb. Osteosarcoma was diagnosed based on histopathologic examination. All abnormal serum analyte concentrations improved immediately after surgery, including azotemia, total calcium, ionized calcium, and PTHrP. The biochemical results were attributed to osteosarcoma causing PTHrP‐induced hypercalcemia.     

Hypercalcemia and parathyroid hormone-related protein in a dog with undifferentiated nasal carcinoma.

Hypercalcemia was discovered in a 7-year-old, castrated male basset hound with a suspected nasal tumor. The dog died the day after admission and nasal carcinoma and disseminated intravascular coagulation were diagnosed on postmortem. Detectable levels of serum PTHrP support a diagnosis of hypercalcemia of malignancy.     

Circulating let‐7g is down‐regulated in Bernese Mountain dogs with disseminated histiocytic sarcoma and carcinomas – a prospective study

Cancer is a prevalent cause of mortality in Bernese mountain dogs (BMDs). Circulating microRNAs (miRNAs) are found in blood and have been identified as promising biomarkers in various neoplastic diseases in humans. In the current study, the expression profile of different types of miRNAs was investigated in healthy BMDs and BMDs with cancer. Seven healthy and six non‐treated BMDs with cancer [four with disseminated histiocytic sarcomas (DHS)] were enrolled in this study. Clinical evaluations including physical examination, blood analysis, urinalysis and diagnostic imaging were performed on all dogs. Twenty‐four different miRNAs were profiled from RNA isolated from whole blood preserved in PAXgene^® tubes using quantitative real‐time PCR (qPCR). The miRNA let‐7g was significantly down‐regulated in dogs with cancer (P = 0.002) and dogs with DHS (P = 0.011) compared with healthy controls. This miRNA is a known tumour suppressor and further analyses are warranted to assess its value as a non‐invasive biomarker for early detection of different types of cancer in BMDs.     

Multifocal cutaneous histiocytic sarcoma in a young dog and review of histiocytic cell immunophenotyping

A 9‐month‐old male Great Dane had progressive generalized nodular dermatopathy for several months. There were > 100 raised, alopecic, firm, painful nodules throughout the skin. Aspirates from several lesions yielded moderate numbers of irregularly round or polygonal to spindle‐shaped cells with mild to moderate anisocytosis and few inflammatory cells, and the cytologic interpretation was proliferation of mesenchymal or histiocytic cells. On histopathologic examination, nodules were composed of densely packed sheets of round to spindle‐shaped cells with mild anisokaryosis and low mitotic activity. Multifocal histiocytic sarcoma with a spindle‐cell pattern was diagnosed based on morphologic features and intense expression of CD18. Additional immunophenotypic analysis on frozen sections of tissue confirmed the diagnosis of histiocytic sarcoma; expression of CD18, CD45, CD1a, CD11b, and CD11c, limited expression of Thy‐1 (CD90) and CD80, and lack of expression of CD4, CD11d, and CD86 indicated that the cells were likely interstitial dendritic cells; a review of reactive and neoplastic dendritic cells is provided. Based on staging, internal organs were not affected. Sequential treatment with lomustine and doxorubicin failed to prevent progression of the cutaneous lesions, and the dog died 3 months after initial diagnosis. At necropsy, a focus of neoplastic cells was present in one lymph node, but except for skin other organs were not involved. The clinical presentation of histiocytic sarcoma may be unusual, and neoplastic cells may lack overt features of malignancy on cytologic and histopathologic examination. In some instances, immunophenotyping is required to differentiate histiocytic sarcoma from other histiocytic disorders.     

Hyperalbuminemia associated with hepatocellular carcinoma in a dog

Abstract: A 12‐year‐old, neutered male, mixed‐breed dog was presented to The Ohio State University Veterinary Teaching Hospital with a history of weight loss and weakness. Laboratory abnormalities reported by the referring veterinarian during the past year included increased alkaline phosphatase (ALP) activity, hyperalbuminemia, and nonregenerative anemia. On referral, the dog appeared hydrated and had moderate muscle wasting and hepatomegaly. A large lobular hepatic mass was observed ultrasonographically. Laboratory results included mild to moderate nonregenerative anemia, urine‐specific gravity of 1.035, 3+ proteinuria, increased serum activities of alanine aminotransferase (229 U/L, reference interval 10–55 U/L), ALP (813 U/L, reference interval 15–120 U/L), and the steroid‐induced isoform of ALP (676 U/L, reference interval 0–6 U/L), marked hyperalbuminemia (5.3 g/dL, reference interval 2.9–4.2 g/dL), and an increased A/G ratio (1.7). Hyperalbuminemia was confirmed by reanalysis on 2 different analyzers and by agarose gel electrophoresis, and colloid osmotic pressure (COP) was markedly increased (42.5 mmHg, reference interval 20–25 mmHg). Cytologic examination of a fine‐needle aspirate of the hepatic mass indicated hepatocellular proliferation; histologic examination of an excisional biopsy confirmed hepatocellular carcinoma. Three weeks after surgery, the albumin concentration, A/G ratio, COP, and ALT activity had normalized, but ALP activities remained high. We hypothesized that hyperalbuminemia developed secondary to hepatocellular carcinoma due to increased synthesis of albumin by malignant hepatocytes or due to decreased negative feedback from impaired hepatocellular osmoreceptivity. Hepatocellular carcinoma has been associated with paraneoplastic secretion of other proteins, but hyperalbuminemia has been reported only once in a human patient and has not previously in dogs.     

Disseminated histiocytic sarcoma with peripheral blood involvement in a Bernese Mountain dog

Abstract: A 6‐year‐old Bernese Mountain dog was presented with a history of lethargy and weight loss of 2 weeks duration. On physical examination the dog had pale mucous membranes and tachypnea. Ultrasound examination revealed hepatomegaly, splenomegaly, and mesenteric lymphadenomegaly. Results of a CBC included marked normocytic normochromic nonregenerative anemia, marked thrombocytopenia, and moderate leukocytosis with mild neutrophilia and a large population of unclassified round cells (6.2 × 10³/μL). The unclassified cells occasionally were bi‐ or multinucleated and had variably abundant pale basophilic cytoplasm that contained multiple irregular clear vacuoles and occasionally erythrocytes. Fine needle aspirate specimens of the mesenteric lymph nodes and spleen were composed of a population of round pleomorphic cells with the same features as the circulating cells. On flow cytometric analysis of peripheral blood, the unclassified cells expressed CD18, CD45, CD11c, CD1c, and CD14; immunocytochemical analysis of blood smears also indicated the cells were positive for CD1c, CD1a, and CD11c. The dog died a few hours after referral. The histologic interpretation of samples collected from spleen, liver, and lymph nodes was malignant neoplasia of histiocytic origin. Immunohistochemical staining yielded negative results for CD11d, a marker of red‐pulp macrophages, ruling out hemophagocytic histiocytic sarcoma. Based on clinical and pathologic findings, the final diagnosis was disseminated histiocytic sarcoma (DHS) with peripheral blood involvement. To our knowledge, DHS in a dog with evidence and immunophenotyping of neoplastic cells in peripheral blood has been reported only rarely.     

Hypercalcemia and high parathyroid hormone-related protein concentration associated with malignant melanoma in a dog

A 12-year-old Cocker Spaniel with an oral malignant melanoma was evaluated for progressive lethargy and anorexia. No metastases were identified during antemortem evaluation, but severe hypercalcemia was evident. Antemortem diagnostic testing failed to identify a cause for the hypercalcemia. No neoplasms other than the melanoma were identified on postmortem examination. Serum parathyroid hormone-related protein concentration was markedly high, and the melanoma had moderate to marked immunostaining for this protein. Paraneoplastic syndromes are rare in dogs with malignant melanoma.     

Paraneoplastic pemphigus in a dog

This report presents a case of paraneoplastic pemphigus in a 7-year-old female Bouvier. The dog initially showed extensive oral ulcerations that exacerbated upon treatment with trimethoprim-sulfadiazine. Subsequently, the dog developed vesiculobullous and ulcerative lesions on the ear margins, the nose, periocular, and at the nail beds. Due to complete therapy resistance and a deteriorating general condition, the dog was euthanized. During post-mortem examination a thymic lymphoma was found. While an early biopsy of the oral cavity revealed features of erythema multiforme, skin lesions at necropsy were typical of pemphigus vulgaris. Indirect immunofluorescence of patient serum revealed an antikeratinocyte membrane pattern typical for pemphigus. The serum was also positive on bovine bladder epithelium. In a Western blot, autoantibodies to a 210 and a 190 kDa protein were detected.     

Identification and preservation of the parathyroid gland during total thyroidectomy in dogs with bilateral thyroid carcinoma: a report of six cases

Simultaneous removal of bilateral thyroid tumors was performed while preserving the parathyroid gland in six dogs. At least one external parathyroid gland was identified in all dogs. In five cases, the external parathyroid gland and its blood supply were preserved intact. In one dog, the vessels supplying the external parathyroid gland had been invaded by the tumor, and the gland was thus removed and reimplanted into the sternohyoid muscle. That dog required postoperative treatment with oral calcium gluconate and vitamin D₃. Local tumor recurrence was not observed in any of the cases. The mean survival time was 920 days. We found that the external parathyroid gland could be identified and preserved in most dogs undergoing total thyroidectomy.     

Hypoglycemia associated with disseminated metastatic tonsillar squamous cell carcinoma producing insulin‐like growth factor‐I in a Pomeranian dog

A 13‐year‐old spayed female Pomeranian dog was presented for persistent, severe hypoglycemia (37 mg/dL; reference interval [RI] 75‐128 mg/dL). Progressive nonregenerative anemia (hematocrit 23.3%‐15.9%; RI 37.0%‐55.0%) and severe thrombocytopenia (36 000/µL; RI 200‐500 000/µL) were also noted. The serum insulin concentration was low (0.24 ng/mL; RI 0.302‐1.277 ng/mL). Computed tomography revealed multiple splenic nodules (1‐6 mm in diameter) and several hepatic nodules (7.6, 12 mm in diameter). Ultrasound‐guided fine‐needle aspiration of the splenic and hepatic nodules revealed low numbers of epithelial cells with mild cellular atypia, suggestive of a metastatic epithelial tumor, but the primary site was unknown at that time. On careful oral examination under general anesthesia, an enlarged right tonsil was noted grossly, and histopathologic examination of the tonsil diagnosed squamous cell carcinoma. Bone marrow aspirates and biopsies of the splenic and hepatic nodules were performed; all samples were diagnosed as metastatic carcinoma on histopathologic examination. No nodules were present in the pancreas, despite careful palpation during exploratory laparotomy. On immunohistochemistry, the neoplastic cells were positive for cytokeratin AE1/3 and insulin‐like growth factor (IGF)‐I but were negative for chromogranin A, PGP9.5, insulin, and inconclusive for IGF‐II. This is the first report of a primary IGF‐I‐producing squamous cell carcinoma in the tonsil of a dog with metastases to bone marrow, liver, and spleen, resulting in hypoglycemia.     

Evaluation of the drug sensitivity and expression of 16 drug resistance-related genes in canine histiocytic sarcoma cell lines

Canine histiocytic sarcoma (HS) is an aggressive tumor type originating from histiocytic cell lineages. This disease is characterized by poor response to chemotherapy and short survival time. Therefore, it is of critical importance to identify and develop effective antitumor drugs against HS. The objectives of this study were to examine the drug sensitivities of 10 antitumor drugs. Using a real-time RT-PCR system, the mRNA expression levels of 16 genes related to drug resistance in 4 canine HS cell lines established from dogs with disseminated HS were determined and compared to 2 canine lymphoma cell lines (B-cell and T-cell). These 4 canine HS cell lines showed sensitivities toward microtubule inhibitors (vincristine, vinblastine and paclitaxel), comparable to those in the canine B-cell lymphoma cell line. Moreover, it was shown that P-gp in the HS cell lines used in this study did not have enough function to efflux its substrate. Sensitivities to melphalan, nimustine, methotrexate, cytarabine, doxorubicin and etoposide were lower in the 4 HS cell lines than in the 2 canine lymphoma cell lines. The data obtained in this study using cultured cell lines could prove helpful in the developing of advanced and effective chemotherapies for treating dogs that are suffering from HS.     

Prior joint disease is associated with increased risk of periarticular histiocytic sarcoma in dogs

Periarticular histiocytic sarcoma (PAHS) is the most common synovial tumour in dogs and is characterized by aggressive local disease with a high rate of distant metastasis. Previously, an association between PAHS and prior joint disease has been demonstrated in the Bernese Mountain Dog breed and suggested in the Rottweiler. We hypothesized that this association would be present in other breeds and investigated this via a retrospective, case‐controlled analysis. Cases were dogs diagnosed with PAHS of the stifle or elbow. Controls were age, breed and sex‐matched dogs without a diagnosis of histiocytic sarcoma. Diagnosis of prior joint disease was determined based on review of medical records and direct veterinarian and owner communications. Data were evaluated using logistic regression, 2‐sampled t tests, and chi‐squared analysis. Our study population consisted of 28 cases and 46 controls, including Flat‐Coated, Golden and Labrador Retrievers, Rottweilers, English Bulldogs, Shih Tzus, Australian Shepherds, Staffordshire Terriers and mixed breed dogs. Dogs with PAHS were more likely to have prior joint disease in the tumour‐affected joint compared with the control population (odds ratio [OR] = 13.42, P < .0001, 95% confidence interval [CI] = 4.33‐48.63). A total of 88.2% of dogs with stifle PAHS had prior joint disease in their tumour‐affected joint, most commonly cranial cruciate ligament rupture. This study confirms that the previously noted association between prior joint disease and PAHS in Bernese Mountain Dogs also applies to other breeds. Additional studies are needed to further investigate for a causal relationship.     

Paraneoplastic hypercalcemia in a dog with thyroid carcinoma

This case report describes a dog with thyroid carcinoma and paraneoplastic hypercalcemia. Following thyroidectomy the dog became hypocalcemic and required supplementation with calcitriol and calcium carbonate. During the following 2 years, attempts to reduce the supplementation resulted in hypocalcemia. The dog died from renal failure with no evidence of thyroid carcinoma.     

Effect of dasatinib in a xenograft mouse model of canine histiocytic sarcoma and in vitro expression status of its potential target EPHA2

Canine histiocytic sarcoma (HS) is an aggressive and highly metastatic tumor. Previously, the kinase inhibitor dasatinib was shown to have potent growth inhibitory activity against HS cells in vitro, possibly via targeting the EPHA2 receptor. Here, the in vivo effect of dasatinib in HS cells was investigated using a xenograft mouse model. Moreover, the expression status of EPHA2 was examined in six HS cell lines, ranging from insensitive to highly sensitive to dasatinib. In the HS xenograft mouse model, dasatinib significantly suppressed tumor growth, as illustrated by a decrease in mitotic and Ki67 indices and an increase in apoptotic index in tumor tissues. On Western blot analysis, EPHA2 was only weakly detected in all HS cell lines, regardless of sensitivity to dasatinib. Dasatinib likely results in the inhibition of xenograft tumor growth via a mechanism other than targeting EPHA2. The findings of this study suggest that dasatinib is a targeted therapy drug worthy of further exploration for the treatment of canine HS.