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Christopher Reetz Department of Veterinary Clinical Sciences, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK 74078.

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Sonia Crochik Department of Veterinary Clinical Sciences, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK 74078.

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Kelci Mckeirnan Department of Veterinary Clinical Sciences, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK 74078.

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Mark Rochat Department of Veterinary Clinical Sciences, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK 74078.

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History

An 8-year-old neutered male Dachshund was evaluated at the Boren Veterinary Medical Teaching Hospital with a history of stranguria, pollakiuria, and incontinence for 3 weeks and signs of back pain and slowly progressive paraparesis for 2 weeks. The dog had been treated for cystitis and suspected prostatitis by the referring veterinarian, with a 1-week course of antimicrobials and meloxicam. The urinary incontinence persisted after treatment, but there was mild improvement in the stranguria and pollakiuria and a subjective decrease in the size of the prostate gland. Approximately 2 years earlier, a T12–T13 hemilaminectomy had been performed for treatment of Hansen type 1 intervertebral disk herniation. The signs of back pain and progressive paraparesis were believed to be the result of an episode of intervertebral disk disease, and cage confinement was initiated. Three days prior to referral, administration of meloxicam was discontinued, and treatment with tramadol and prednisone was initiated. The owner reported that the dog had been dribbling urine, was only able to urinate and defecate small amounts at a time, had begun trying to bite when picked up, and was weak in the pelvic limbs.

Physical examination revealed severe signs of pain in the lumbar vertebral area and caudal aspect of the abdomen, an asymmetrically enlarged and painful prostate gland, pelvic limb paraparesis, conscious proprioceptive deficits in the pelvic limbs, and pelvic limb hyperreflexia. Anal tone and perineal reflexes were normal; the urinary bladder was distended, and urine was difficult to express. Abdominal radiography was performed to evaluate the prostate gland (Figure 1).

Figure 1—
Figure 1—

Lateral (A) and ventrodorsal (B) radiographic views of the abdomen of an 8-year-old neutered male Dachshund evaluated because of a 3-week history of stranguria, pollakiuria, and signs of pain on palpation over the lumbar vertebral area (L3–L4 region).

Citation: Journal of the American Veterinary Medical Association 242, 1; 10.2460/javma.242.1.35

Determine whether additional imaging studies are required, or make your diagnosis from Figure 1—then turn the page →

Diagnostic Imaging Findings and Interpretation

The prostate gland is enlarged with suspected subtle pinpoint areas of mineralization (Figure 2). An approximately 5 × 3-cm, somewhat oblong soft tissue mass is present in the sublumbar region, at the level of L4–L6, consistent with enlarged sublumbar lymph nodes. Poorly defined proliferative bone response is evident in the ventral aspects of the vertebral bodies from L4 through L7. The body of L5 is slightly less opaque than the adjacent vertebrae, and osteolysis is suspected. Well-defined proliferative bone response is present on the medial aspect of the right ilium. Portions of the thorax included in the abdominal projections reveal the presence of lung nodules; therefore, pulmonary metastasis is suspected. The radiographic findings are most consistent with prostatic neoplasia with metastases to the sublumbar lymph nodes, lumbar vertebrae, pelvis, and lungs.

Figure 2—
Figure 2—

Same radiographic views as in Figure 1. A—Mineralized areas are suspected in the prostate gland (arrowheads). Mineralized areas are present in the sublumbar lymph node, which is larger than normal (arrows). Poorly defined response is evident in multiple lumbar vertebral bodies (irregular arrows). The body of L5 is more radiolucent than normal (white curved arrows). B—The pedicle of L5 is lytic (arrowhead), and periosteal proliferation is evident in the medial aspect of the right ilium (arrow). In both panels, suspected pulmonary nodules are visible (black curved arrows).

Citation: Journal of the American Veterinary Medical Association 242, 1; 10.2460/javma.242.1.35

Ultrasonography was performed to further assess the prostate gland, evaluate possible extension of the tumor into the urinary bladder or ureteral region, and search for metastases. The prostate gland was grossly abnormal and measured 3 × 2.5 cm on the sagittal plane. Multiple hypoechoic and hyperechoic areas were observed, along with a cavitated region (Figure 3). At least 2 sublumbar (medial iliac) lymph nodes were enlarged and contained hyperechoic, hypoechoic, and mineralized areas. The largest lymph node measured 2.4 × 4.4 cm. A mass was observed extending from the prostate gland into the urinary bladder, including the trigone region, and severe right hydronephrosis and hydroureter were present.

Figure 3—
Figure 3—

Ultrasonographic images of the abdomen of the same dog as in Figure 1. Images were obtained to further assess the prostate gland, evaluate possible extension of the tumor into the urinary bladder or ureteral region, and search for metastases. A—Sagittal plane of the prostate gland (within calipers). Notice the hypoechoic, hyperechoic, and suspected mineralized areas (arrowhead). B—Parasagittal plane of the enlarged sublumbar lymph node (between arrows). Also note the hypoechoic, hyperechoic, and suspected mineralized areas (arrowheads).

Citation: Journal of the American Veterinary Medical Association 242, 1; 10.2460/javma.242.1.35

Treatment and Outcome

Ultrasound-guided fine-needle aspirations of the sublumbar lymph nodes and prostate gland were performed; a cytologic diagnosis of carcinoma was made in both organs. Thoracic radiography revealed the presence of multiple pulmonary nodules, most consistent with metastatic disease.

The prognosis for prostatic neoplasia is poor, with most affected dogs being euthanized within 10 days after diagnosis.1,2 The owners of the dog of this report also elected euthanasia.

Comments

Prostatic carcinoma is an uncommon tumor in dogs. Evidence of an increased rate of occurrence in neutered males exists, with 1 study1 finding 2.38 times as great a risk of developing prostatic carcinoma for neutered males, compared with that for sexually intact dogs. One of the most commonly reported sites of metastases is the regional lymph nodes.1,2 Additional sites of metastases include the lungs, liver, bones, colon and rectum, and urinary tract organs.1,2

Prostatic mineralization can be associated with prostatitis, benign prostatic hyperplasia, paraprostatic cysts, and neoplasia. In neutered dogs, the suspicion for prostatic neoplasia increases substantially in the presence of mineralization. In the dog of the present report, although the radiographic evidence for prostatic mineralization was subtle, the mineralization was also observed on ultrasonography, increasing our suspicion of prostatic neoplasia.

Bone lesions associated with prostatic carcinoma can be osteoproliferative or osteolytic or a mixture of both.1–3 The most common sites of bone lesions are the lumbar vertebrae, pelvis, and femur, but other bones, especially those of the appendicular skeleton, can be affected.1,2 Although many of these lesions represent metastatic disease, some purely proliferative lesions are found to be consistent with hypertrophic osteopathy1,3 or periostitis secondary to adjacent sublumbar lymph node inflammation.1 Patients with skeletal lesions associated with the lumbar vertebrae or pelvic limbs often have signs of pain, gait stiffness, or weakness similar to the signs seen in the dog of the present report.

Sublumbar lymphadenopathy can be associated with both neoplastic and nonneoplastic disease.3,4 Sublumbar lymph nodes with heterogeneous echogenicity have been shown to be useful in identifying malignant lymph nodes.5

The presence of hydronephrosis and hydroureter is explained by obstruction of the ureteral papilla by the mass in the trigone. Based only on the cytologic evidence of carcinoma, a tumor arising from the urinary bladder extending to the prostate gland could be another differential diagnosis; however, mineralization of an enlarged prostate gland in the neutered male dog of the present report, along with sublumbar lymphadenopathy, osteoproliferative and osteolytic lesions in the lumbar vertebrae and pelvis, and soft tissue pulmonary nodules, made the diagnosis of metastatic prostatic neoplasia more likely.

References

  • 1. Bell FW, Klausner JS, Hayden DW et al. Clinical and pathologic features of prostatic adenocarcinoma in sexually intact and castrated dogs: 31 cases (1970–1987). J Am Vet Med Assoc 1991; 199:16231630.

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  • 2. Cornell KK, Bostwick DG, Cooley DM et al. Clinical and pathologic aspects of spontaneous canine prostate carcinoma: a retrospective analysis of 76 cases. Prostate 2000; 45:173183.

    • Crossref
    • Search Google Scholar
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  • 3. Feeney DA, Johnston GR, Klausner JS et al. Canine prostatic disease—comparison of radiographic appearance with morphologic and microbiologic findings: 30 cases (1981–1985). J Am Vet Med Assoc 1987; 190:10181026.

    • Search Google Scholar
    • Export Citation
  • 4. Bradbury CA, Westropp JL, Pollard RE. Relationship between prostatomegaly, prostatic mineralization, and cytologic diagnosis. Vet Radiol Ultrasound 2009; 50:167171.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 5. Llabres-Diaz FJ. Ultrasonography of the medial iliac lymph nodes in the dog. Vet Radiol Ultrasound 2004; 45:156165.

  • Figure 1—

    Lateral (A) and ventrodorsal (B) radiographic views of the abdomen of an 8-year-old neutered male Dachshund evaluated because of a 3-week history of stranguria, pollakiuria, and signs of pain on palpation over the lumbar vertebral area (L3–L4 region).

  • Figure 2—

    Same radiographic views as in Figure 1. A—Mineralized areas are suspected in the prostate gland (arrowheads). Mineralized areas are present in the sublumbar lymph node, which is larger than normal (arrows). Poorly defined response is evident in multiple lumbar vertebral bodies (irregular arrows). The body of L5 is more radiolucent than normal (white curved arrows). B—The pedicle of L5 is lytic (arrowhead), and periosteal proliferation is evident in the medial aspect of the right ilium (arrow). In both panels, suspected pulmonary nodules are visible (black curved arrows).

  • Figure 3—

    Ultrasonographic images of the abdomen of the same dog as in Figure 1. Images were obtained to further assess the prostate gland, evaluate possible extension of the tumor into the urinary bladder or ureteral region, and search for metastases. A—Sagittal plane of the prostate gland (within calipers). Notice the hypoechoic, hyperechoic, and suspected mineralized areas (arrowhead). B—Parasagittal plane of the enlarged sublumbar lymph node (between arrows). Also note the hypoechoic, hyperechoic, and suspected mineralized areas (arrowheads).

  • 1. Bell FW, Klausner JS, Hayden DW et al. Clinical and pathologic features of prostatic adenocarcinoma in sexually intact and castrated dogs: 31 cases (1970–1987). J Am Vet Med Assoc 1991; 199:16231630.

    • Search Google Scholar
    • Export Citation
  • 2. Cornell KK, Bostwick DG, Cooley DM et al. Clinical and pathologic aspects of spontaneous canine prostate carcinoma: a retrospective analysis of 76 cases. Prostate 2000; 45:173183.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 3. Feeney DA, Johnston GR, Klausner JS et al. Canine prostatic disease—comparison of radiographic appearance with morphologic and microbiologic findings: 30 cases (1981–1985). J Am Vet Med Assoc 1987; 190:10181026.

    • Search Google Scholar
    • Export Citation
  • 4. Bradbury CA, Westropp JL, Pollard RE. Relationship between prostatomegaly, prostatic mineralization, and cytologic diagnosis. Vet Radiol Ultrasound 2009; 50:167171.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 5. Llabres-Diaz FJ. Ultrasonography of the medial iliac lymph nodes in the dog. Vet Radiol Ultrasound 2004; 45:156165.

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