A Solitary Plasmacytoma in a Dog with Progression to a Disseminated Myeloma

Solitary plasmacytomas are rare occurrences in dogs, consequently their potential for malignancy is undetermined. A solitary plasmacytoma was removed from the perianal region of a dog. The dog was clinically normal at that time, but was killed one year later as a result of hind limb stiffness and uremia. At the postmortem examination a disseminated myeloma was found, involving the vertebral column, liver, spleen, bone marrow and visceral lymph nodes.     

Surgical decompression,with or without adjunctive therapy,for palliative treatment of primary vertebral osteosarcoma in dogs

Vertebral osteosarcoma (OSA) is the most common primary vertebral tumor in dogs, however studies examining the survival time after surgical decompression of these tumors are limited. There is also limited information regarding the benefit of adjunctive treatments such as radiation therapy or chemotherapy in these patients. The goal of this study was to determine survival time of dogs with primary vertebral OSA after palliative decompressive surgery alone and combined with radiation therapy and/or chemotherapy. Records from 22 client‐owned dogs diagnosed with primary vertebral OSA and treated with decompressive surgery were collected retrospectively from eight referral institutions. Survival time was assessed for dogs treated with surgery alone as well as dogs who received adjunctive radiation therapy and/or chemotherapy. Median survival time in the 12 dogs treated with surgery alone was 42 days (range: 3‐1333 days). The three dogs treated with surgery and chemotherapy had a median survival time of 82 days (range: 56‐305 days). Only one dog was treated with surgery and radiation therapy; this dog survived 101 days. Six dogs were treated with surgery, radiation therapy and chemotherapy; these dogs had a median survival time of 261 days (range: 223‐653 days). Cause of death in all cases that survived the initial postoperative period was euthanasia secondary to confirmed or suspected tumor regrowth. The results of this study suggest that definitive radiation therapy, possibly combined with concurrent chemotherapy, significantly improves survival in dogs treated with palliative decompressive surgery for vertebral OSA and should be the treatment of choice in selected cases.     

Neurological signs and MRI findings in 12 dogs with multiple myeloma

Vertebral lesions and associated neurological signs occur in dogs with multiple myeloma, however, veterinary literature describing MRI findings is currently lacking. The objective of this multicenter, retrospective, case series study was to describe neurological signs and MRI findings in a group of dogs that presented for spinal pain or other neurological deficits and had multiple myeloma. Electronic records of four veterinary referral hospitals were reviewed. Dogs were included if they had a pathologically confirmed diagnosis of multiple myeloma, had presented for spinal pain or other neurological signs, and had undergone MRI of the vertebral column. The MRI studies were evaluated and the anatomical location of lesion(s), signal intensity, presence of extra‐dural material, degree of spinal cord compression, extent of vertebral lesions, and contrast enhancement were recorded. Twelve dogs met inclusion criteria. Most dogs (n = 8) had a chronic progressive history, with varying degrees of proprioceptive ataxia and paresis (n = 11), and spinal pain was a feature in all dogs. The MRI findings were variable but more consistent features included the presence of multiple expansile vertebral lesions without extension beyond the outer cortical limits of affected vertebrae, and associated extradural material causing spinal cord compression. The majority of lesions were hyper‐ to isointense on T2 (n = 12) and T1‐weighted (n = 8) sequences, with variable but homogeneous contrast‐enhancement (n = 12). These described MRI characteristics of multiple myeloma may be used to aid early identification and guide subsequent confirmatory diagnostic steps, to ultimately improve therapeutic approach and long‐term outcome.     

Canine Osteosarcoma

Osteosarcoma was diagnosed in 38 dogs. Thirty-six tumors originated from the appendicular skeleton and two from the axial skeleton. Nineteen of the dogs were treated with amputation alone, and 19 were treated with amputation and adjuvant chemotherapy consisting of doxorubicin and cisplatin. The 36 dogs with appendicular osteosarcoma had complete amputation of the affected limb, whereas the two dogs with osteosarcoma of the axial skeleton had an en bloc resection. The mean survival of the 19 dogs treated with amputation alone was 218 days (median, 175 days). Ten dogs were alive at 6 months and four survived 1 year. None of the dogs survived longer than 16 months. Radiographic lesions consistent with metastatic osteosarcoma were seen after surgery in the nine dogs in which radiographs were taken. The mean survival of the 19 dogs treated with amputation and chemotherapy was 415 days (median, 300 days). Drug toxicity was not observed. Fifteen dogs were alive at 6 months, seven dogs were alive at 1 year, 5 dogs were alive at 2 years, and two dogs were alive at 3 years or longer. One dog is alive and well at 25 months. Radiographic lesions suggestive of metastatic osteosarcoma developed in the other 18 dogs. The 19 dogs treated with amputation and chemotherapy had significantly longer survival times than the dogs treated with amputation alone.     

Progression of cutaneous plasmacytoma to plasma cell leukemia in a dog

A 5‐year‐old male neutered Bernese Mountain Dog was presented for cutaneous plasmacytoma, which was treated by surgical excision. Four months later, the dog developed multiple skin masses, hyphema, pericardial and mild bicavitary effusions, myocardial masses, and marked plasmacytosis in the peripheral blood. Circulating plasma cells expressed CD34 and MHC class II by flow cytometry. Immunocytochemistry demonstrated that these cells were strongly positive for multiple myeloma oncogene 1/interferon regulatory factor 4 (MUM‐1) and weakly to moderately positive for Pax5. The dog was hypoglobulinemic but had a monoclonal IgA gammopathy detected by serum immunofixation electrophoresis. The PCR analysis of antigen receptor gene rearrangements (PARR) by fragment analysis using GeneScan methodology revealed that plasmacytoid cells in the original cutaneous plasmacytoma and peripheral blood had an identical immunoglobulin heavy chain gene (IgH) rearrangement, indicating that both populations were derived from the same neoplastic clone. Canine cutaneous plasmacytoma rarely progresses to a malignant form and plasma cell leukemia is rarely diagnosed in the dog. This report describes a case of cutaneous plasmacytoma progressing to plasma cell leukemia with a rapid and aggressive clinical course. This report also highlights the utility of flow cytometry, immunocytochemistry, immunofixation electrophoresis, and PARR by fragment analysis using GeneScan methodology in the diagnosis of this hematopoietic neoplasm.     

Monoclonal gammopathies in the dog: a retrospective study of 18 cases (1986-1999) and literature review

Eighteen dogs with monoclonal gammopathies were evaluated retrospectively. Most of the cases were associated with lymphoproliferative tumors (i.e., nine multiple myelomas, one Waldenstr?m's macroglobulinemia, one lymphoma, one chronic lymphocytic leukemia, and one mucocutaneous plasmacytoma). The prevalence of nonmyelomatous monoclonal gammopathies (28%) was also significant (three leishmaniasis and two ehrlichiosis). Presenting complaints and clinical signs often were nonspecific or related to bleeding diathesis. Significant laboratory findings included proteinuria, hypoalbuminemia, and anemia. Some unusual features were also observed: a multiple myeloma with immunoglobulin M secretion, another myeloma with two narrow spikes on the electrophoretic pattern, and a mucocutaneous plasmacytoma secreting an immunoglobulin G paraprotein.     

Surgical excision of primary canine rectal tumors by an anal approach in twenty-three dogs

OBJECTIVE: To describe an anal approach for excision of primary rectal tumors in dogs and to report outcome. STUDY DESIGN: Retrospective study. ANIMALS: Dogs (n=23) with primary rectal tumors. METHODS: Review of medical records (1990-2000) of dogs with primary rectal neoplasia excised surgically using an anal approach with rectal prolapse. With dogs anesthetized, the rectum was prolapsed, stabilized with stay sutures during tumor excision with 1 cm margins to the level of the muscularis, then the rectal mucosa was sutured. RESULTS: Each dog had only 1 tumor type (adenocarcinoma [8], solitary polyp [5], carcinoma [4], plasmacytoma [2], adenoma [1], leiomyoma [1], mucinous carcinoma [1], and papilloma [1]). Mean tumor volume was 3.1 cm(3) (range 0.1-37.7 cm(3)). Postoperative complications (rectal bleeding [5], tenesmus [4]) were mild and resolved within 7 days after surgery; another dog had partial mucosal dehiscence identified at 6 days. The primary tumor was incompletely excised in 1 dog (4.3%), and local recurrence occurred 16 and 24 months after surgery in 2 dogs. Outcome beyond the immediate postoperative period was known for 18 dogs, including 2 dogs still alive. Mean postoperative disease-free interval for these 18 dogs was 36.8 months (range 5-84 months). CONCLUSION: Surgical excision of tumors of the caudal rectum can be accomplished through the anus after rectal prolapse. CLINICAL RELEVANCE: An anal approach facilitated by rectal prolapse should be considered as a viable option for the surgical treatment of selected cases of tumors of the caudal aspect of the rectum in dogs.     

Analysis of Survival in a Retrospective Study of 86 Dogs with Brain Tumors

A retrospective study of 86 dogs with brain tumors was undertaken. Sixty-nine dogs had histologic confirmation of tumor type, whereas the remaining 17 dogs had CT evidence of a brain tumor. All dogs had neurologic abnormalities. Seven dogs received no treatment, 38 dogs received only symptomatic treatment, and 41 dogs received some form of definitive treatment, in addition to medical management. Types of definitive treatment included surgery, cobalt-60 radiation, whole-body hyperthermia, 125I implants, and chemotherapy, alone or in combination. The factor that was most associated with survival duration was mode of therapy. Those dogs who were treated with cobalt-60 radiation, with or without other combinations of therapy, lived significantly longer than dogs who received surgery (+/- 125I implants), or dogs who received symptomatic treatment (P = 0.01 and P less than 0.001, respectively). After statistic adjustment for treatment, multiplicity of brain involvement (solitary vs. multiple) provided prognostic information with respect to survival (P = 0.001), with dogs who had a solitary site of involvement having a better prognosis. After further adjustment, initial neurologic dysfunction (mild/moderate vs. severe) showed significance as prognostic variable (P = 0.005). Both the mild and moderate groups had a more favorable prognosis compared with dogs who had severe initial neurologic impairment. The median survival time for the 86 dogs was 1.0 month (range: 1 day-42.4 mo). Median survival times of dogs receiving: 1) no therapy or only symptomatic therapy, 2) surgery (+/- 125I), or 3) cobalt-60 radiation (+/- hyperthermia, +/- surgery) were 0.2, 0.9, and 4.9 months, respectively.     

Closed fluoroscopic-assisted spinal arch external skeletal fixation for the stabilization of vertebral column injuries in five dogs

Objective— To evaluate outcome after closed fluoroscopic-assisted application of spinal arch external skeletal fixators in dogs with vertebral column injuries.
Study Design— Retrospective case series.
Animals— Dogs with traumatic vertebral column injuries (n=5).
Methods— Medical records of dogs with vertebral column fractures and/or luxations stabilized with spinal arch external skeletal fixator frames applied using a closed fluoroscopic-assisted technique were reviewed. Owners were contacted to obtain long-term clinical outcomes.
Results— Five dogs (age range, 6–72 months; weight, 10–54 kg) had traumatic vertebral column injuries stabilized with spinal arch external skeletal fixators applied in closed fashion. Injuries involved vertebral segments of the thoracolumbar junction, lumbar spine, and lumbosacral junction. Immediately postoperatively, 4 dogs had anatomic alignment of their vertebral fracture/luxation; 1 dog had 1 mm of vertebral canal height compromise. Time to fixator removal ranged from 65 to 282 days (141±87 days). All dogs had regained satisfactory neurologic function by 3 months. At long-term follow-up (range, 282–780 days; mean 445±190 days) all dogs were judged to have good to excellent return of function by their owners.
Conclusion— Successful closed fluoroscopic-assisted application of external skeletal fixators using spinal arches provided satisfactory reduction with few complications in 5 dogs. Return to function was judged to be good to excellent in all dogs at long-term evaluation.
Clinical Relevance— Closed fluoroscopic-assisted application of ESF using spinal arches provided satisfactory reduction and effective stabilization of spinal fractures with few complications and should be considered as a treatment approach.     

SPINAL MAST CELL TUMORS IN DOGS: IMAGING FEATURES AND CLINICAL OUTCOME OF FOUR CASES

Published information regarding canine vertebral column mast cell tumors (MCTs) is limited. The objectives of this study were to report clinical and advanced imaging findings for a group of dogs with confirmed spinal MCT. Inclusion criteria for this retrospective case series were dogs with spinal magnetic resonance imaging (MRI) or computed tomography (CT) scans and a histological diagnosis of spinal MCT. Clinical, imaging, treatment, and outcome data were recorded. Four dogs met inclusion criteria. One dog had primary spinal MCT and three dogs had metastatic spinal MCT. All four dogs presented for paraspinal hyperesthesia and subacute progressive or acute myelopathy. All CT and MRI lesions were extradural. Two cases exhibited distinct masses in the epidural space. In one case, an epidural tumor invaded from the paravertebral musculature. One case exhibited polyostotic lesions indistinguishable from multiple myeloma by MRI. One dog with a primary epidural low‐grade MCT remains clinically normal 4 years postoperatively, following adjunctive lomustine. An epidural high‐grade MCT, metastatic from a cutaneous tumor, recurred within 2 months of surgery despite adjunctive vinblastine. Two high‐grade cases with concurrent visceral involvement were euthanized immediately after imaging. In dogs, MCT should be considered as a differential diagnosis for a progressive painful myelopathy and CT or MRI evidence of an extradural spinal lesion (epidural, paravertebral, or polyostotic). While more often associated with cutaneous or disseminated disease, MCT may also occur as a primary tumor of the epidural space in dogs.     

Solitary extramedullary plasmacytoma of the canine larynx

An 11-year-old, female, spayed cocker spaniel was presented with dysphonia caused by a solitary laryngeal mass. Excisional biopsy was performed, and a diagnosis of plasmacytoma was made on the basis of histological examination. Further investigations showed no signs of systemic involvement. Coarse fractionated radiation therapy failed to control the tumour. Therapy was successfully instituted with a conventional combination chemotherapy protocol over a period of 14 months. The dog remains disease free 30 months after diagnosis. Most solitary, extramedullary plasmacytomas in dogs arise in the gastrointestinal tract, with fewer reports in other sites. The larynx is an uncommon sight of involvement in any species, and to the authors' knowledge, this is the first report of this tumour type in the canine larynx. In contrast to the therapeutic benefits reported in humans, the combination of surgery and radiation therapy was unsuccessful in this case, although sustained remission was gained following chemotherapy.     

Serum protein electrophoresis in 147 dogs

Reference intervals for serum protein electrophoresis (SPE) were created from a group of 75 clinically healthy dogs and compared with SPE results obtained from clinical cases presented to the University of Bristol over an eight-and-a-half-year period. A total of 147 dogs, in which SPE had been performed, had complete case records available and thus met the inclusion criteria. Signalment and final diagnoses taken from the case records and SPE results were divided into normal and abnormal based on the newly established reference intervals. Cases were grouped according to the SPE protein fraction abnormalities and diagnosis using the DAMNITV classification system. Of the 147 cases, 140 (95.2 per cent) had abnormal SPE results. The most common protein fraction abnormality was decreased albumin (59.3 per cent) followed by a polyclonal increase in γ globulins (38.6 per cent). Decreased β-1 globulins and increased β-2 globulins were documented in 36.4 and 30.0 per cent of cases, respectively. The most common DAMNITV classification associated with abnormal SPE results was infectious/inflammatory disease, which was diagnosed in 79 of 140 cases (56.4 per cent). Monoclonal gammopathies were noted in eight dogs (5.7 per cent), and underlying lymphoproliferative disease was present in all cases where a diagnosis was achieved, including multiple myeloma (four dogs), splenic plasmacytoma (one dog), hepatic plasmacytoma (one dog) and lymphoma (one dog).     

Magnetic resonance imaging characteristics of suspected vertebral instability associated with fracture or subluxation in eleven dogs

The purpose of this study was to describe the magnetic resonance imaging (MRI) characteristics of suspected instability in dogs with vertebral fractures or subluxations. Eleven dogs that had MRI examinations of the spine prior to surgical stabilization of vertebral fractures and/or subluxations were included in the study. Nine dogs also had survey radiographs. Four dogs had cervical fracture or fracture-subluxation and presented with tetraplegia with intact nociception (n = 2) or nonambulatory tetraparesis (n = 2). Seven dogs had thoracolumbar fracture-subluxation or subluxation and presented with paraplegia with intact nociception (n = 5) or nonambulatory paraparesis (n = 2). A three-compartment model was applied to the interpretation of both the radiographic and MRI studies. Radiography identified compartmental disruption consistent with spinal instability in seven out of the nine cases radiographed. In MRI studies, rupture of the supportive soft tissue structures and/or fracture in at least two compartments could be visualized. Nine cases had spinal cord changes on MRI including signal intensity changes, swelling, compression, and intramedullary hemorrhage. Paravertebral muscle intensity changes were also visible at each trauma site. Magnetic resonance imaging provided helpful information on the location and extent of damage to supportive soft tissue structures and enabled assessment of spinal cord injury in this group of dogs with surgically confirmed vertebral fractures and subluxations.     

Progression of a solitary, malignant cutaneous plasma-cell tumour to multiple myeloma in a cat

An 11‐year‐old male domestic shorthair cat was examined because of a soft‐tissue mass on the left tarsus previously diagnosed as a malignant extramedullary plasmacytoma. Findings of further diagnostic tests carried out to evaluate the patient for multiple myeloma were negative. Five months later, the cat developed clinical evidence of multiple myeloma based on positive Bence Jones proteinuria, monoclonal gammopathy and circulating atypical plasma cells. This case represents an unusual presentation for this disease and documents progression of an extramedullary plasmacytoma to multiple myeloma in the cat.     

Surgical treatment of lumbosacral instability caused by discospondylitis in four dogs

OBJECTIVE: To describe a surgical technique involving distraction and stabilization of the lumbo-sacral vertebral segment using an external skeletal fixator in dogs with lumbosacral instability caused by discospondylitis. STUDY DESIGN: Retrospective clinical study. ANIMALS: Four client-owned dogs. METHODS: Medical records of all dogs diagnosed with discospondylitis from 1994 to 1997 were identified and reviewed. Four dogs with lumbosacral discospondylitis requiring surgical treatment were then specifically studied. Surgical technique, clinical signs, preoperative diagnostic investigation, radiographic findings, and the results of short-term and long-term reevaluations were recorded. RESULTS: Twelve dogs with discospondylitis were identified, 4 of which had lumbosacral discospondylitis. These 4 dogs underwent surgical distraction and stabilization because they failed to respond to medical treatment. Three dogs received a cancellous bone graft between L7 and S1 and had rapid interbody fusion of this vertebral segment. The dog that did not receive a graft did not have interbody fusion at the time of fixator removal. This did not affect the final clinical outcome. Lumbosacral pain and neurological deficits present before surgery rapidly subsided after the procedure. All dogs received concurrent antibiotic treatment for a minimum of 4 weeks. All dogs were clinically normal at the time of fixator removal and all continued to do well during the follow-up period (8-48 months; mean, 27.5 months). CONCLUSION AND CLINICAL RELEVANCE: Lumbosacral discospondylitis may not respond well to conservative treatment because of the mobility of the affected space. Surgical treatment involving distraction and stabilization to obtain intervertebral fusion is very effective in treating lumbosacral instability caused by discospondylitis.     

Radiographic evaluation of congenital vertebral anomalies in Korean raccoon dogs (Nyctereutes procyonoides koreensis)

BackgroundThe normal vertebral anatomy of Korean raccoon dogs and their variants require research attention as a prerequisite for identifying pathologies and anomalies.ObjectivesThis retrospective study aimed at describing the vertebral formula and congenital vertebral anomalies in Korean raccoon dogs (Nyctereutes procyonoides koreensis).MethodsRadiographs of 82 raccoon dogs (42 males, 40 females) acquired from May 2013 to June 2020 in the Gangwon Wildlife Medical Rescue Center were reviewed to evaluate the cervical, thoracic, and lumbar vertebrae of the spine.ResultsNormal morphology of all vertebrae was observed in 50 of the 82 raccoon dogs, and the vertebral formula was cervical 7, thoracic 13, and lumbar 7. Congenital vertebral anomalies were found in 32 raccoon dogs: transitional vertebrae (TV) in 31 and block vertebrae in 2. Two raccoon dogs had 2 types of vertebral anomalies: one had TV and block vertebra, and the other had 2 types of TV. Twenty-nine raccoon dogs had thoracolumbar TV (TTV) and 3 had lumbosacral TV. TTV was morphologically classified into 4 different types: unilateral extra-rib in 5 raccoon dogs, bilateral extra-ribs in 14, bilateral elongated transverse processes in 4, and an asymmetric mixed formation of extra-rib with elongated transverse process in 6.ConclusionsThis study showed that TTV is common in Korean raccoon dogs, and that the vertebral formula is relatively diverse. The bilateral extra-ribs type TTV is the most common variant, which is almost similar to normal rib to be confused the radiographic evaluation.     

Distraction–Fusion for Caudal Cervical Spondylomyelopathy Using an Intervertebral Cage and Locking Plates in 14 Dogs

Objective: To evaluate clinical and radiographic outcome in dogs with caudal cervical spondylomyelopathy (CCSM) treated with an intervertebral fusion cage and locking plates. Study Design: Prospective clinical study. Animals: Large breed dogs (n=14) with CCSM. Methods: Dogs had single level cervical spine distraction/fusion performed using an intervertebral cage with a hollow center filled with cancellous autograft and 2 ventrally applied locking plates. Outcome was measured using neurologic scores and radiographic interpretation 6 weeks, 6 months, and 12 months postoperatively. Results: The surgical procedure was well tolerated in all dogs. Final outcome at 12 months was available in 9 dogs. Five dogs were judged excellent, 1 dog was good, 2 dogs were satisfactory, and 2 dogs were poor because of adjacent segment disease. Four dogs died for reasons unrelated to the procedure. Radiographically, implants remained stable over the entire follow‐up period. The disc space continued to fill with an immature pattern of new bone, which showed progressive increase in opacity and quantity. Subsidence of the cage (median 2 mm) was detected in 9 dogs at 6 weeks and remained unchanged in those that could be followed further. Conclusion: Distraction–fusion of single level CCSM in dogs with a combination of intervertebral cage and ventral locking plates is clinically effective and results in successful bony fusion.     

Immunoglobulin A multiple myeloma with cutaneous involvement in a dog

An 8-year-old rottweiler, diagnosed with multiple myeloma and multiple sites of cutaneous involvement, was treated with chemotherapy and radiation therapy. The diagnostic criteria for canine multiple myeloma, limitations of diagnostic testing for light chain proteinuria in dogs, and the role of radiation therapy in multiple myeloma patients is discussed.