Surgery and radiation therapy for extramedullary plasmacytoma of the penile mucosa in a dog

A 10-year-old neutered male Italian greyhound dog was presented because it had a penile plasmacytoma. Surgery followed by radiation therapy resulted in local control and survival for 1688 days. This is the first report of surgery and definitive radiation therapy for curative intent therapy of extramedullary penile plasmacytoma in a dog.     

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.     

A metastatic secretory gastric plasmacytoma with aberrant CD3 expression in a dog

A 10‐year‐old crossbred dog was presented with a 6‐week history of hematemesis, melena, anorexia, and lethargy. Clinical evaluation revealed a gastric mass with a regional lymphadenomegaly as well as a monoclonal gammopathy manifesting as hyperglobulinemia. Cytologic and histopathologic analyses were consistent with a round cell neoplasm; neoplastic cells showed nuclear immunoreactivity for MUM1 and diffuse cytoplasmic reactivity for CD3. Polymerase chain reactions performed on fixed and fresh tissue identified a clonal rearrangement with an IgH primer set. An extramedullary plasmacytoma (EMP) was confirmed by cellular morphology and molecular diagnostics. Following an objective response to chemotherapy, the dog was euthanized 8 months after diagnosis, and a postmortem examination confirmed the clinical findings. This is the first reported case of a monoclonal gammopathy secondary to a gastric EMP coupled with aberrant expression of CD3 in an aggressive plasmacytic tumor, and highlights the utility of molecular diagnostics for classifying atypical hemolymphoid neoplasms.     

Extramedullary plasmacytoma of the third eyelid gland in a dog

A case of extramedullary plasmacytoma of the third eyelid gland in a 7-year-old American Cocker Spaniel is reported. An enlargement of the third eyelid gland, abundant mucopurulent discharge, mild hyperemia and corneal pigmentation in the OD was present. Excisional biopsy of the mass revealed the gland was infiltrated and partially destroyed by a uniform population of neoplastic plasma cells. The neoplastic cells were positive for CD138, Ki-67 and λ light chain. CD20, CD3, κ light chain and cytokeratin were negative. Twelve months following surgery, no recurrence was observed. To the authors' knowledge, this is the first extramedullary plasmacytoma of the third eyelid gland reported 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.     

Nodular immunocyte-derived (AL) amyloidosis in the trachea of a dog

A 7-year-old castrated male Miniature Schnauzer was examined because of labored breathing and episodes of respiratory distress that progressed to collapse. On cervical radiographs, a focal soft tissue mass in the caudal cervical portion of the trachea was observed, and during tracheoscopy, a 1 x 1 cm, pedunculated, multinodular, pink, intraluminal mass extending from the dorsal tracheal membrane and obstructing approximately 80% of the tracheal lumen was seen. Tracheal resection and anastomosis was performed to remove the mass, and the dog recovered without complications. On histologic examination, the mass consisted of a large accumulation of homogeneous, faintly fibrillar eosinophilic material admixed with a predominantly plasma cell infiltrate; examination of sections stained with thioflavin T and Congo red stain confirmed that the eosinophilic material was amyloid. A diagnosis of nodular, immunocyte-derived (AL) amyloidosis was made. Seventeen months after surgery, the dog had a relapse of respiratory distress because of an extramedullary plasmacytoma involving the trachea.     

Extramedullary laryngeal plasmacytoma in a dog

Abstract

CASE HISTORY:?An 8-year-old, female, spayed Border Collie presented with a 3-week history of coughing, choking and haemoptysis.

CLINICAL FINDINGS:?Inspiratory stridor was evident on clinical examination. Cervical radiographs revealed a round soft-tissue mass on the dorsal aspect of the epiglottis. A laryngeal mass was evident on examination under anaesthesia, and an incisional biopsy was obtained. Histopathology revealed a dense proliferation of neoplastic round cells morphologically consistent with plasma cell origin. Immunohistochemisty results were negative for CD3 (T cell marker) and positive for CD79a (B cell marker), resulting in a diagnosis of extramedullary plasmacytoma. The patient was treated with melphalan and prednisolone; clinical signs resolved within 1 week and the mass was no longer evident on laryngoscopy after 1 month of treatment. After 6 months of chemotherapy, the laryngeal mass recurred and euthanasia was requested. There was no evidence of systemic spread on post-mortem examination.

DIAGNOSIS:?Solitary extramedullary plasmacytoma of the canine larynx.

CLINICAL RELEVANCE:?Respiratory extramedullary plasmacytomas are extremely rare with only one laryngeal and two tracheal cases previously reported. This is the first published report of a laryngeal plasmacytoma that recurred despite combination chemotherapy with melphalan and prednisolone.     

Zygomatic sialocele secondary to infarction treated with sialoadenectomy in a dog

Zygomatic salivary gland disease is not commonly reported in dogs and there is a paucity of literature reporting salivary gland disease secondary to infarction in dogs. A 9-year-old German wirehaired pointer presented with left eye exophthalmos, 3rd eyelid elevation, negative retropulsion, and pain upon opening of the mouth. Computed tomography revealed a mass extending from the left zygomatic salivary gland, consistent with a sialocele. A left-sided zygomatic sialoadenectomy was performed successfully. Histopathologic diagnosis concluded zygomatic salivary gland infarction. The dog had no signs of recurrence 20 mo after surgery.Key clinical message:To the authors’ knowledge, this is the first case report with long-term outcome of a zygomatic sialocele secondary to salivary gland infarction in a dog treated by zygomatic sialoadenectomy via zygomatic osteotomy.     

Concurrent renal amyloidosis and thymoma resulting in a fatal ventricular thrombus in a dog

Thymoma‐associated nephropathies have been reported in people but not in dogs. In this report, we describe a dog with thymoma and concurrent renal amyloidosis. A 7‐year‐old castrated male Weimaraner was presented for progressive anorexia, lethargy, and tachypnea. The dog was diagnosed with azotemia, marked proteinuria, and a thymoma that was surgically removed. Postoperatively, the dog developed a large left ventricular thrombus and was euthanized. Necropsy confirmed the presence of a left ventricular thrombus and histopathology revealed renal amyloidosis. We speculate that the renal amyloidosis occurred secondary to the thymoma, with amyloidosis in turn leading to nephrotic syndrome, hypercoagulability, and ventricular thrombosis. This case illustrates the potential for thymoma‐associated nephropathies to occur in dogs and that dogs suspected to have thymoma should have a urinalysis and urine protein creatinine ratio performed as part of the pre‐surgical database.     

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.     

Bilateral intracorporeally sutured inguinal herniorrhaphy using 3-dimensional laparoscopy in a dog

A 7-month-old, intact male, mixed breed dog with bilateral inguinal hernias underwent general anesthesia for laparoscopic bilateral inguinal herniorrhaphy via a 3-port approach. A 3-dimensional laparoscopic system was used to perform the procedure immediately following prescrotal open castration. Intracorporeal suturing with polypropylene was performed, and 2 cruciate sutures were placed to close each inguinal ring. The caudal aspect of each inguinal ring was left slightly open so as not to disrupt the passage or patency of vessels and nerves. No intra- or post-operative complications occurred. One year after surgery, the dog has no evidence of recurrence of the inguinal hernias.Key clinical message:This case report demonstrates a novel minimally invasive approach to inguinal herniorrhaphy in a dog with no reported complications and a good long-term outcome. Intracorporeally sutured inguinal herniorrhaphy is feasible in dogs with good results, although additional cases are needed to gain experience with this technique in dogs with varying presentations of inguinal hernias.     

Left ventricular outflow tract obstruction caused by a congenital accessory mitral valve leaflet and treated by open-heart surgery in a young dog

A 3-month-old Shetland sheepdog presented with a loud ejection murmur and exercise intolerance. Echocardiography revealed an accessory mitral valve leaflet, characterised by a valve-like structure separate from the mitral valve seen in the subaortic region of the ventricular septum. The left ventricular outflow tract was partially obstructed with a pressure gradient of 12 mmHg. Accessory mitral valve leaflet resection and mitral valvuloplasty were performed during open-heart surgery. Histology performed on the membrane-like structures were indicative of fibrous connective tissues. Postoperative echocardiography confirmed removal of the valve-like structure with resolution of the left ventricular outflow tract obstruction. The pressure gradient was decreased to 4.6 mmHg. The dog was in good condition and no further treatment was required 5 months after surgery. Both cardiac troponin I and NT-proBNP were markedly decreased. In this dog, surgical resection combined with mitral valve plasty resolved the left ventricular outflow tract obstruction and the clinical signs.     

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).     

Tumoral calcinosis in a dog with chronic renal failure

A 2-year-old male German shepherd dog in poor bodily condition was evaluated for thoracic limb lameness due to a large, firm mass medial to the left cranial scapula. Radiography revealed several large cauliflower-like mineralized masses in the craniomedial left scapula musculature, pectoral region and bilaterally in the biceps tendon sheaths. Urinalysis, haematology and serum biochemistry showed that the dog was severely anaemic, hyperphosphataemic and in chronic renal failure. The dog was euthanased and a full post mortem performed. A diagnosis of chronic renal failure with secondary hyperparathyroidism was confirmed. The mineralised masses were grossly and histopathologically consistent with a diagnosis of tumoral calcinosis. Tumoral calcinosis associated with chronic renal failure that does not involve the foot pads is rarely seen.     

A sacro‐caudal spinal cord choroid plexus papilloma in a shar‐pei dog

A seven‐year‐old shar‐pei dog was referred because of severe lumbosacral pain and faecal incontinence of 20 days’ duration. Neurological examination was characterised by plegic tail, absence of perineal reflex, dilated anus, perineum and tail analgesia, and severe lumbosacral pain. The neurological clinical signs were suggestive of a selective lesion involving sacral and caudal spinal cord segments and/or related nerve roots. A magnetic resonance imaging of lumbosacral spine was performed and was suggestive of an intradural lesion. Primary or secondary neoplasia was considered as the most probable differential diagnosis. The dog was euthanased upon the owner's request. Histopathological examination confirmed the presence of an intradural‐extramedullary neoplastic tissue enveloping intradural tract of spinal nerve roots. On the basis of histological and immunohistochemical findings, a diagnosis of well‐differentiated choroid plexus papilloma was made. To the authors's knowledge, this is the first case of primary or metastatic spinal choroid plexus papilloma in dogs.     

Cavitary pulmonary lesion associated with Aspergillus fumigatus infection in a German shepherd dog

A two-year-old female German shepherd dog was presented with chronic cough and haemoptysis. Thoracic radiographs revealed a thin-walled cavitary lesion within a consolidated left cranial lung lobe. Bronchoalveolar lavage confirmed a concurrent bacterial infection; however, despite antibiotic and anthelmintic therapy the clinical signs failed to resolve. A left cranial lung lobectomy was performed. Histopathology and fungal culture confirmed the presence of Aspergillus fumigatus. The necrotic cavity had features compatible with a bronchial origin, possibly a form of cystic bronchiectasis, arising either as a congenital anomaly or acquired secondary to infection. Surgery provided resolution of clinical signs for just over a year before the dog deteriorated again and was subsequently euthanised. Necropsy was declined by the owners. This case report presents a unique presentation in which the predominant clinical sign was coughing due to pulmonary involvement. Aspergillus fumigatus was isolated from the left cranial lung lobe.     

Bilateral ectopic ureters in a male dog with unilateral renal agenesis

A 1-year-old neutered male mixed-breed dog was evaluated because of signs of urinary incontinence. Retrograde positive contrast urethrocystography and excretory urography with pneumocystography revealed bilateral intramural ectopic ureters and absence of the right kidney. During abdominal exploratory surgery, only the left kidney was located. The left intramural ectopic ureter was repaired by neoureterostomy (creation of a new opening for the ureter to enable urine to empty into the bladder). The right ectopic ureter was ligated at its entrance into the urinary bladder serosa. Results of excretory urography (performed immediately after surgery and repeated 8 weeks later) revealed successful correction of the left intramural ectopic ureter. Twelve weeks after surgery, the dog remained continent. To the authors' knowledge, there are few reports of ectopic ureters in male dogs; furthermore, the urinary tract abnormalities detected concurrently in this dog are also unusual.     

Surgical treatment of a double aortic arch in a dog

An 8-month-old spayed female Labrador retriever dog was evaluated for regurgitation 6 months after surgery for a suspected vascular ring anomaly. The dog had a history of regurgitation and slow development as a puppy. An initial left-sided exploratory thoracotomy was unsuccessful in identifying and treating a vascular ring anomaly. The dog was subsequently presented to the PennVet Emergency Service for regurgitation. Thoracic radiography showed cranial thoracic esophageal dilation and an esophageal foreign body that was then removed endoscopically. Subsequent computed tomographic (CT) angiography revealed a double aortic arch. A left 4th intercostal space thoracotomy was performed. The smaller left aortic arch and a left ligamentum arteriosum were ligated and transected. The dog recovered uneventfully and was healthy at the 1-month follow-up visit. This is the 5th reported successful surgical correction of a double aortic arch in a dog. Computed tomographic angiography was essential in diagnosis and surgical planning.Key clinical message:Although uncommon, double aortic arches can occur and present a diagnostic and surgical challenge when a persistent right aortic arch is suspected. Computed tomographic angiography provides an accurate preoperative diagnosis and allows for surgical planning.