Prostatic adenocarcinoma in a castrated dog

Atypical prostatic adenocarcinoma was diagnosed in a castrated dog. The gland was of normal size, contrary to what has been reported in most other cases in dogs. Metastases were not seen, even though radiography suggested metastasis to the external iliac lymph nodes and histologic examination revealed the neoplasm to have a moderately malignant character. Even though hormones have been implicated as a cause of prostatic adenocarcinoma in man, the development of such a neoplasm in dogs castrated at an early age, as exemplified by this case, may cast doubt on that hypothesis.     

Firm rib mass aspirate from a dog

A 9-year-old intact male Miniature Schnauzer presented laterally recumbent, cachexic, and dehydrated with multiple firm bone masses and a bilaterally enlarged prostate. Fine-needle aspiration of a rib mass revealed numerous basophilic polygonal to fusiform cells predominantly found in small to large clusters. The cells exhibited cytologic criteria of malignancy and infrequently displayed large cytoplasmic vacuoles containing finely- to coarsely-stippled azurophilic material. The cytologic diagnosis was metastatic adenocarcinoma and was suspected to be prostatic or transitional cell in origin because of the azurophilic vacuoles within malignant cells. Gross and histologic findings confirmed the clinical and cytologic diagnosis of prostatic adenocarcinoma with widespread metastasis. Cytochemical and immunohistochemical investigation confirmed glycogen was a component of the vacuolar material. The vacuoles observed in the tumor in this case are not a consistent finding in tumors of the prostate or urinary bladder; however, when associated with an epithelial tumor, they may aid in limiting the differentials of the primary tumor and in the selection of further diagnostics.     

Study of prostatic disease in dogs: 177 cases (1981-1986).

Historical and physical signs associated with prostatic disease diagnosed in dogs over a 5.5-year period were defined. One hundred seventy-seven male dogs were determined to have prostatic abnormality. Of the 177 dogs, 87 were determined to have specific prostatic disease. The most common prostatic disease identified in this study was bacterial prostatitis, followed by prostatic cyst, prostatic adenocarcinoma, and benign hyperplasia. The most common prostatic disease identified in neutered dogs was prostatic adenocarcinoma. Mean age at onset of prostatic disease was 8.9 years; statistically significant difference was not observed between age at onset of the various types of prostatic disease identified. Doberman Pinscher was the most common breed with prostate disease. Twenty-nine percent of dogs with a specifically identifiable prostatic disease had signs of systemic illness, 41% had signs of lower urinary tract disease, 28% had signs of gastrointestinal tract abnormalities, and 13% had signs of locomotor difficulty.     

Serum total prostatic and non-prostatic acid phosphatase in healthy dogs and in dogs with prostatic diseases

Total acid phosphatase (TAP), prostatic acid phosphatase (PAP) and non-prostatic acid phosphatase (NPAP) serum concentrations were determined using a spectrophotometric technique in 52 healthy dogs, 15 male dogs suffering from non-prostatic diseases and in 19 dogs suffering from prostatic diseases (12 dogs with benign prostatic hypertrophy and seven dogs with prostatic adenocarcinoma). TAP, PAP and NPAP serum concentrations did not differ between normal male and normal female dogs. Dogs with prostatic adenocarcinoma had significantly higher TAP, PAP and NPAP serum concentrations than dogs with benign prostatic hypertrophy, normal dogs and dogs with non-prostatic disease. The authors conclude that low serum concentrations of TAP and PAP do not rule out prostatic adenocarcinoma in the dog, but elevated concentrations can be useful criteria for the diagnosis of canine prostatic cancer.     

Hepatocellular carcinoma in black-tailed prairie dogs (Cynomys ludivicianus): tumor morphology and immunohistochemistry for hepadnavirus core and surface antigens

From 1994 to 2002, tissues from 61 prairie dogs were submitted to Northwest ZooPath for histopathology. Of these, 12 (20%) had hepatocellular carcinoma (HCC). Three were pets submitted from private veterinary practices. The others were submitted from zoos in the United States. All were adults, ranging from young adult to 7 years of age, with average age of 5.1 years. The most common clinical signs were weight loss, lethargy, palpable abdominal mass, and respiratory difficulty. All tumors were well-differentiated HCCs in which four histologic patterns were recognized. The trabecular pattern was predominant in nine tumors, and the pseudoglandular pattern was predominant in two tumors. The pelioid pattern was also represented in eight tumors. A papillary pattern was present in one case. In seven cases vacuolar change resembling lipidosis was present in the neoplastic hepatocytes of both primary and metastatic tumors. Anaplasia was mild to moderate in most tumors, but a marked degree of anaplasia was noted in the metastatic foci of the case with papillary differentiation. Metastasis to lung was noted in five cases. One of these also had metastasis to the spleen, and another had metastasis to heart and mediastinum. In two cases there was concurrent hepatitis and in two cases, cirrhosis. All tumors and nonneoplastic liver stained negatively for woodchuck hepatitis virus surface and core antigens, and orcein and Victoria blue positive staining of hepatocytes typical of hepadnavirus infection in humans and woodchucks was not present. HCC is apparently common in captive prairie dogs. The hepatic neoplasia observed in prairie dogs was similar to that associated with hepadnaviral infection in humans, woodchucks, and ground squirrels, but no direct evidence of hepadnaviral infection was detected. The rate of metastasis in captive prairie dogs was higher than that reported in woodchucks.     

Evaluation of Serum and Seminal Plasma Markers in the Diagnosis of Canine Prostatic Disorders

Serum and seminal plasma concentrations or activities of acid phosphatase (AP), prostate specific antigen (PSA), and canine prostate specific esterase (CPSE) were measured in normal dogs, dogs with benign prostatic hyperplasia (BPH), dogs with bacterial prostatitis, and dogs with prostatic carcinoma to determine if these assays would be of value in differentiating dogs with prostatic carcinoma from normal dogs, and dogs with other prostatic disorders. In addition, tissue sections of prostatic adenocarcinomas were stained with antiprostatic AP, anti-CPSE, and anti-PSA antibodies to determine if these would be suitable immunohistochemical markers of prostatic carcinoma. Prostate-specific antigen was not detected in canine serum or seminal plasma. Serum and seminal AP activities did not differ significantly between normal dogs and those with prostatic diseases, or among dogs with different prostatic disorders. Serum CPSE activities were significantly higher in dogs with BPH than in normal dogs. Mean serum CPSE activities in dogs with BPH, bacterial prostatitis, and prostatic carcinoma were not significantly different from each other. Slight to moderate immunohistochemical staining of canine prostatic adenocarcinomas was noted for prostatic AP and PSA; most tumors did not stain for CPSE. These results show that proteins of prostatic origin appear in the serum of dogs as a result of prostatic pathology, especially BPH. Canine prostatic adenocarcinoma does not appear to be associated with significant increases in CPSE or AP activities, possibly because of down-regulation of these enzymes by prostatic carcinoma cells. It is also possible that failure to detect significant differences resulted from limited statistical power for some groups and pairwise analyses because of the small number of dogs evaluated.     

PROSTATIC REFLUX DURING POSITIVE CONTRAST RETROGRADE URETHROGRAPHY IN THE DOG

Forty-five positive contrast retrograde urethrograms in which contrast medium reflux into the prostate was identified were evaluated to determine whether a correlation existed between the time and pattern of reflux and the nature of the prostatic disease. Prostatic diseases identified included prostatitis (25 dogs), prostatic tumor (13 dogs), and prostatic hyperplasia (1 dog). Six dogs with contrast medium reflux had no evidence of prostatic disease. No correlation was found between presence of prostatic reflux and specific prostatic diseases; however, prostatic tumor or infection was observed more frequently than hyperplasia, metaplasia, or cyst in the dogs with contrast medium reflux. A linear pattern and irregular, indistinct margination of the contrast medium reflux were associated with prostatitis; however, these patterns were also observed in dogs without prostatic disease     

Canine prostatic disease--comparison of radiographic appearance with morphologic and microbiologic findings: 30 cases (1981-1985)

A retrospective analysis was made of radiographs from 24 clinically normal young adult male Beagles used in previously reported base-line research on the distal male urinary tract. The ventrodorsal and craniocaudal prostate gland dimensions were measured, as visualized on the lateral radiographic view, and expressed as a ratio of the distance between the cranial aspect of the public bone and the sacral promontory. In 17 of these 24 dogs, there was sufficient image clarity to permit confident measurement of prostatic dimensions. From these data, the largest acceptable prostatic dimension, as visualized on the lateral radiographic view, was 70% of the public-promontory distance. A retrospective analysis was made of 30 cases of canine prostatic disease, with the objective of identifying the radiographic (survey and distention retrograde urethrocystogram) appearance most often associated with the various spontaneous prostatic diseases. Prostatomegaly was not specific for the cause of prostatic disease, except if the apparent parenchymal dimensions were greater than or equal to 90% of the public-promontory distance wherein neoplasia, abscess, and paraprostatic cysts (readily differentiated from diffuse intraparenchymal disease by ultrasonography) were the principle considerations. Multifocal, irregularly shaped, parenchymal mineral densities were observed only in dogs with prostatic carcinoma (4/7 cases) or prostatitis (1 case of chronic prostatitis). Narrowing of the prostatic portion of the urethra was observed only in association with abscess, neoplasm, or noninflammatory nonneoplastic disease (possibly benign hypertrophy/hyperplasia), whereas widening of this part of the urethra was not observed.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of an extract of Serenoa repens on dogs with hyperplasia of the prostate gland

OBJECTIVE: To determine effects of an extract of Serenoa repens on dogs with prostatic hyperplasia. ANIMALS: 20 mature male dogs with benign prostatic hyperplasia. PROCEDURE: Dogs were assigned to 3 comparable groups on the basis of prostatic volume per kg of body weight and degree of prostatic hyperplasia determined histologically. Dogs in 2 groups were treated for 91 days (8 received 500 mg, PO, q 8 h [1,500 mg/d], and 6 received 100 mg, PO, q 8 h [300 mg/d]). The control group of 6 dogs did not receive medication. Effects of treatment on prostatic volume, prostatic weight, prostatic histologic characteristics, radiographic and ultrasonographic assessment of prostatic size, results of CBC, serum biochemical analyses, and urinalysis, serum testosterone concentration, and semen characteristics were determined. At the termination of the study, all dogs were euthanatized, and necropsies were performed. Investigators conducting tests and interpreting results were not aware of treatment group of each dog. RESULTS: Treatment did not affect prostatic weight, prostatic volume, or prostatic histologic scores, libido, semen characteristics, radiographs of the caudal portion of the abdomen, prostatic ultrasonographs, or serum testosterone concentrations. Results of CBC, serum biochemical analyses or urinalysis, and body weights did not change during treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Treatment with an extract of S repens for 91 days did not significantly affect the prostate gland of dogs. Adverse effects were not evident. Although products containing extracts of S repens are widely advertised for men with prostatic hyperplasia, beneficial or harmful effects of this plant extract were not found in dogs with prostatic hyperplasia.     

Comparison of concurrent imaging modalities for staging of dogs with appendicular primary bone tumours

This study assessed the use of whole body computed tomography (CT) for the evaluation of metastasis in dogs with primary appendicular bone tumours compared to long bone survey radiography, bone scintigraphy and thoracic radiographs. Fifteen dogs were included in this pilot study. A construct reference standard was used for detection of bone metastasis, and negative thoracic radiographs were compared against CT. Definitive lesions were only identified on bone scintigraphy. Not all lesions agreed with the construct reference standard. No definitive lesions were identified on survey radiographs or CT. Lesions were identified on thoracic CT that were not visible radiographically. Equivocal ground glass pulmonary lesions progressed in three of four cases. Whole body CT was not a suitable alternative to bone scintigraphy; however, it was useful as an adjunctive diagnostic modality. Pulmonary lesions were visible on CT that were not seen radiographically and ground glass pulmonary lesions in dogs should be considered suspicious for metastasis.     

Association between lymph node size and metastasis in dogs with oral malignant melanoma: 100 cases (1987-2001)

OBJECTIVE: To determine the association between lymph node size and metastasis and to assess measurement of lymph node size as an accurate and reliable means of tumor staging in dogs with oral malignant melanoma. DESIGN: Retrospective study. ANIMALS: 100 dogs with histologically confirmed oral malignant melanoma. PROCEDURE: Clinical records for dogs with oral malignant melanoma were reviewed. Data regarding size and results of cytologic or histologic examination of lymph nodes were evaluated. The association between lymph node size and metastasis was determined. RESULTS: Forty-seven (47%) dogs, of which 23 (49%) had enlarged mandibular lymph nodes, had no cytologic or histologic evidence of metastasis. Of 53 (53%) dogs with cytologic or histologic evidence of mandibular lymph node metastasis, 37 (70%) had enlarged mandibular lymph nodes, and 16 (30%) had mandibular lymph nodes of normal size. Overall, 16 of the 40 (40%) dogs with normal-sized lymph nodes had microscopic evidence of metastatic disease. Sensitivity and specificity of lymph node size as a predictor of metastasis were 70 and 51%, respectively, and the positive and negative predictive values were 62 and 60%, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Although a significant relationship was identified between lymph node size and metastasis to the lymph node, this association did not appear strong enough to be clinically relevant. Results suggest that lymph node size alone is insufficient for accurate clinical staging of oral malignant melanoma in dogs; cytologic or histologic examination of regional lymph nodes should routinely be performed, regardless of size of those nodes.     

Diagnostic value of alkaline phosphatase isoenzyme separation by affinity electrophoresis in the dog.

Affinity electrophoresis, using wheat germ lectin, was used to separate the alkaline phosphatase isoenzymes in the sera of 150 dogs with alkaline phosphatase values greater than or equal to 150 IU/L. The method provided clearer separation of the liver, bone and steroid-induced alkaline phosphatase isoenzymes commonly observed in canine serum, compared to conventional cellulose acetate electrophoresis. The dogs were divided into four patient groups determined by previous corticosteroid treatment, evidence of elevated endogenous corticosteroid levels, age and alanine aminotransferase values. The isoenzyme pattern of each patient was qualitatively assessed. The isoenzyme pattern most frequently observed was greater than 50% steroid induced alkaline phosphatase, which was present in 76 of 150 dogs. This pattern was observed in 18 of 22 dogs receiving corticosteroid therapy, two of three dogs with hyperadrenocorticism, and in dogs with a variety of other diagnoses. The majority of immature dogs (12 of 20) had an isoenzyme pattern consisting of greater than 50% bone. The majority of dogs with active hepatocellular injury (16 of 27) had greater than 50% liver isoenzyme. The isoenzyme pattern was not specific for certain diseases, therefore the diagnostic usefulness is limited. However the isoenzyme result is useful in some cases to determine which further diagnostic tests are indicated, and to determine the source of alkaline phosphatase elevation.     

RELATIONSHIP BETWEEN PROSTATOMEGALY, PROSTATIC MINERALIZATION, AND CYTOLOGIC DIAGNOSIS

Canine prostatic disease is commonly evaluated with abdominal ultrasound and radiographs. Mineralization of the prostate is often reported, but the clinical relevance of this finding is currently not known. The purpose of this study was to characterize the relationship between ultrasonographic and radiographic prostate mineralization and the final diagnosis. Medical records of 55 dogs with evidence of prostatomegaly or prostatic mineralization and a cytologic diagnosis were evaluated. Radiographs and ultrasound images were assessed for caudal retroperitoneal lymphadenopathy, vertebral lesions, or other signs of metastasis, and mineralization was assessed semiquantitatively. Twenty-two of 55 (40%) dogs had prostatic neoplasia. Regarding neoplasia, mineralization in neutered dogs had a positive predictive value (PPV) of 100%, a negative predictive value (NPV) of 50%, and a sensitivity and specificity of 84% and 100%, respectively. Mineralization in intact dogs had a PPV of 22%, an NPV of 96%, and a sensitivity and specificity of 67% and 77%, respectively. All neutered dogs with prostatomegaly but not prostatic neoplasia had bacterial prostatitis and were castrated within the previous 3 months. Intact dogs with prostatomegaly and mineralization but not neoplasia had paraprostatic cysts ( n =3), benign prostatic hyperplasia ( n =2) or prostatitis ( n =2). Mineralization score was not indicative of neoplasia. In conclusion, neutered dogs with prostatic mineralization were very likely to have prostatic neoplasia. Intact dogs were unlikely to have prostatic neoplasia if no mineralization was found on radiographs or ultrasound.     

Effects of castration on chronic bacterial prostatitis in dogs

An Escherichia coli bacterial prostatitis was experimentally induced in dogs to determine the effect of castration on chronic bacterial prostatitis. Two weeks after instillation of bacteria directly into the prostate gland, 17 of 22 adult mixed-breed male dogs had positive urine or prostatic fluid cultures or both. Seven of the 17 dogs were randomly chosen to be castrated, and 10 of the 17 served as sham-operated controls. At weekly intervals, urine was obtained from 17 dogs for aerobic microbiologic culturing. At each week, dogs with no bacterial growth in the cultured urine had prostatic fluid collected for aerobic microbiologic culture. Dogs with negative urine, prostatic fluid, and prostatic tissue needle biopsy culture results at week 7 were euthanatized. For remaining dogs, weekly cultures were continued until the dogs were euthanatized at week 12. None of the 7 castrated dogs and 6 of the 10 dogs subject to sham operation had prostatic infection at the time of necropsy. The castrated dogs had a mean infection duration of 4.2 weeks, which was statistically shorter than the 9.5-week mean duration of infection in the sham-operated controls. Cultures of prostatic tissue obtained immediately after euthanasia correlated 100% with urine and prostatic fluid cultures taken before euthanasia. All of the 6 dogs with positive prostatic cultures at termination had moderate to marked lymphoplasmacytic chronic prostatitis. The 11 dogs that were not infected at the end of the study had normal to moderate lymphoplasmacytic chronic prostatitis on histologic examination.(ABSTRACT TRUNCATED AT 250 WORDS)     

Postoperative adjuvant treatment of invasive malignant mammary gland tumors in dogs with doxorubicin and docetaxel

BACKGROUND: Treatment outcome after surgery alone is unsatisfactory in dogs with invasive malignant mammary gland tumors. HYPOTHESIS: Adjuvant doxorubicin or docetaxel will improve the treatment outcome in dogs with high-risk malignant mammary gland tumors, and the use of docetaxel will be feasible in affected dogs. ANIMALS: Thirty-one dogs with malignant mammary gland tumors of histologic stages II and III (vascular or lymphatic invasion, regional lymph node metastasis, or distant metastasis) were used. METHODS: A prospective clinical trial in which dogs were treated with surgery alone (n = 19) or also received adjuvant chemotherapy (n = 12) with doxorubicin or docetaxel was conducted. Docetaxel was given as an IV infusion at a dose of 30 mg/m2 preceded by dexamethasone and diphenhydramine administration. RESULTS: The recurrence-free interval ranged from 13 to 2,585 days (median not reached); the median metastasis-free interval and overall survival were 294 days and 370 days, respectively. Dogs treated with chemotherapy had a tendency toward higher long-term local control and survival rates, but there was no significant difference in the recurrence-free interval (P = .17), time to metastasis (P = .71), and overall survival (P = .12). Factors found to influence the time to metastasis and overall survival included lymph node metastasis (P = .009) and tumor fixation to underlying structures (P = .043, time to metastasis), as well as age (P = .018) and histologic stage (P < .001, survival). Mild allergic skin reactions were the most frequently observed complications of docetaxel treatment. CONCLUSIONS AND CLINICAL IMPORTANCE: Chemotherapy did not lead to an improved outcome in this population. Docetaxel treatment was well tolerated. Additional investigations of adjuvant chemotherapy in dogs with high-risk mammary cancer are warranted.     

Age-related changes in the prostate and testes of the beagle dog.

Age-related changes in the histologic morphology of the Beagle dog prostate have been used as a model for similar changes that occur in human beings. Previous studies of the aging changes in Beagle dogs have been limited to animals less than 10 years of age. In this study, the prostate, testes, and serum testosterone levels were evaluated in healthy Beagle dogs that were grouped by age to provide five groups of dogs that ranged from 3 to 14 years of age. Tissue sections from the prostate and testes were examined qualitatively and quantitatively by light microscopy. All animals 6 years of age and older had histologic characteristics of complex benign prostatic hyperplasia. A mean statistically significant increase in prostatic weight with increased age was noted (mean value 1.08 +/- 0.22 g/kg body weight at 3 years of age, increasing to 2.64 +/- 0.37 g/kg body weight at 14 years of age). Morphometric analysis of the prostatic tissue suggested that similar to the change observed in human males, the increase in size was primarily due to an increase in the absolute volume of interstitial tissues (mean value 2.8 +/- 1.1 cm3 at 3 years of age, increasing to 7.4 +/- 1.3 cm3 at 14 years of age). The epithelial component did not contribute to the increase noted, with the exception that the percentage of glandular lumen did increase with age, indicating progressive cystic dilatation of the glands.(ABSTRACT TRUNCATED AT 250 WORDS)     

Postoperative radiotherapy and mitoxantrone for anal sac adenocarcinoma in the dog: 15 cases (1991–2001)

The medical records of 15 dogs with anal sac adenocarcinoma (ASAC) treated with concurrent curative‐intent radiotherapy and mitoxantrone (MX) after surgical removal of the primary tumour were reviewed retrospectively. Radiation was prescribed at 15 daily fractions of 3.2 Gy for a total dose of 48 Gy. MX was given intravenously at a dosage of 5 mg m^?2 every 3 weeks for five treatment sessions. Twelve dogs received pelvic irradiation to include the regional lymph nodes (LNs) and three received radiation only to the perineum. At the time of diagnosis, four dogs were hypercalcaemic and seven dogs presented with regional LN metastasis. All the dogs with regional LN metastasis received pelvic irradiation, and in three cases, metastatic LNs were treated in the macroscopic disease setting. The median event‐free survival was 287 days, and the median overall survival was 956 days. Acute and chronic radiation complications were common and non‐life threatening, although chronic complications contributed to the decision to euthanize two dogs. The results observed in this retrospective analysis compare favourably with cases of ASAC in the literature related to treatment with surgery and/or chemotherapy.     

Retrospective outcome evaluation for dogs with surgically excised,solitary Kiupel high‐grade,cutaneous mast cell tumours

Published outcomes for dogs with specifically high‐grade mast cell tumours (MCTs), controlled for clinical stage, are few. Clinical outcomes for 49 dogs with Kiupel high‐grade, clinical stage I, cutaneous MCTs were evaluated. Median survival time (MST) was 1046 days; 1 and 2‐year survival rates were 79.3% and 72.9%, respectively. At study end 24 dogs had died, 23 dogs were alive (median follow‐up 980 days) and 2 dogs were lost to follow‐up. Death was considered MCT‐related in 14 of 20 dogs with a known cause of death. Local tumour recurrence developed in nine dogs (18.4%); regional lymph node metastasis occurred in six dogs (12.2%); and a new MCT developed in 15 dogs (30.1%). Tumour location, histologic margin size and use of chemotherapy did not affect MST; increasing mitotic count (P = .001) and increasing tumour diameter (P = .024) were independently negatively prognostic. Six dogs that developed lymph node metastasis after surgery had worse MST (451 days) than 42 dogs that did not develop metastasis (1645 days); (P < .001). Our study suggests that dogs with local surgical control of clinical stage I histologically high Kiupel grade cutaneous MCT may have a long survival time; especially those with smaller tumours and a lower mitotic count. Our results suggest that evaluation of staging information and mitotic count may be equally helpful as histologic grading when making a prognosis; and highlight the importance of not relying on histologic grade alone when predicting survival for dogs with MCT.