Cyclosporine-responsive granulomatous sebaceous adenitis in a dog

Granulomatous sebaceous adenitis was diagnosed in a 2 year old spayed Miniature Pinscher. Initial treatment with isotretinoin for 3 weeks resulted in little response and decreased tear production. Immunosuppressive doses of prednisone for 3 weeks resulted in mild response of the dermatitis; however, the dog developed transient diabetes mellitus secondary to this treatment. Cyclosporine (5 mg/kg of body weight, po, q 12 h) resulted in good clinical response for 12 months, but histologically, the sebaceous glands remained absent. Although cyclosporine has immunosuppressive properties, this drug also has inhibitory effects of keratinocyte proliferation. These mechanisms may explain the beneficial response of cyclosporine in the treatment of granulomatous sebaceous adenitis in this dog.     

Intramedullary spinal cord metastasis of a primary lung tumour in a dog

A dog was presented with signs of subacute, progressive myelopathy. A tentative diagnosis of a diffuse intramedullary spinal cord mass was made using contrast radiography (myelography). At autopsy a solitary, large bronchoalveolar carcinoma was detected in a lung lobe. Histological examination of the cranial thoracic spinal cord revealed a tumour which was similar, but not identical, to the lung tumour. Immunohistochemistry helped to confirm that the spinal lesion was a metastasis of the lung tumour.     

Mammary carcinoma with sebaceous differentiation in a dog

This report describes an invasive mammary carcinoma with a rare distinctive feature characterized by sebaceous differentiation of tumor cells. This tumor occurred in a 10-year-old female mixed breed dog. The patient had two masses in the left fifth mammary gland. Grossly, the masses were firm, whitish to light brown, and superficially ulcerated. On cut surface, they were multilobulated with foci of necrosis. Microscopically, the tumors were composed of two distinctive neoplastic components, intraductal papillary adenocarcinoma and sebaceous carcinoma. The regions of sebaceous tumor were clumped separately, contained well-developed sebaceous cells and keratinized epithelial cells, and were surrounded by few to several layers of basaloid cells. The cells with abundant foamy cytoplasm that resembled sebaceous cells were also found within the intraductal papillary-like nests of mammary carcinoma, providing evidence of sebaceous metaplasia. Sebaceous differentiation in a mammary gland tumor is possible, because skin appendages and ductal apparatus of the mammary gland share a common anlagen. This tumor had an aggressive behavior with lymphatic metastasis. Consequentially, the dog had a poor prognosis.     

Pulmonary Echinococcus multilocularis metastasis in a dog

A young adult Labrador retriever dog was presented for surgical debulking of hepatic alveolar echinococcosis. Computed tomography detected hepatomegaly with multiple large cavitary masses with extension of tissue from a lesion wall into the caudal vena cava and numerous nodules in all lung lobes. Following euthanasia, histology confirmed parasitic vesicles with granulomatous reaction in all lesions, and polymerase chain reaction (PCR) established the causative agent to be Echinococcus multilocularis. This report is the first to present imaging features of pulmonary E. multilocularis granulomata in a dog.     

Cutaneous metastasis of a colonic carcinoma in a dog

An entire seven-year-old Afghan bitch was referred with a two month history of pruritic, erythematous and ulcerated lesions involving the skin of the ventral abdomen, caudal mammae, inguinal region and the inner thighs. Other clinical signs included pyrexia, mild dyspnoea, mammary hypertrophy and lactation. A skin biopsy confirmed an anaplastic carcinoma. At necropsy, the neoplasm was located in the colon, urinary bladder, liver, peritoneal wall, diaphragm, parietal pleura and mediastinal membranes, including the pericardial sac attachment. The colon was considered to be the primary site.     

Mesojejunoileac liposarcoma with intrahepatic metastasis in a dog

We report a liposarcoma at the mesojejunoileum that was widely excised, and then the intrahepatic metastatic liposarcoma was found. The dog was treated by two single-agent chemotherapy separately. The patient was an 8-year-old, male Dachshund, and was referred to our hospital owing to the significant distention of the left abdomen. Neither radiography nor ultrasonography detected the actual association of the tumor with the abdominal viscera before surgery. A large-sized tumor mass that adhered to the mesojejunoileum was explored by laparatomy. Final diagnosis of a pleomorphic liposarcoma was made by the routine histology and further identified by Oil Red O stain. The two single-agent chemotherapy including doxorubicin followed by capecitabine, however, failed to cause remission of the intrahepatic metastatic lesions. The patient died 22 months after operation and the cause of death was supposed to be metastatic liposarcoma.     

Priapism secondary to penile metastasis in a dog

A 4-year-old, male Newfoundland cross was presented for lethargy, anorexia, and dysuria. The main clinical finding was an enlarged and painful prostate gland. While the dog was hospitalized, priapism developed. Following euthanasia, microscopic examination revealed that a carcinoma involving both bladder and prostate gland had widely metastasized to the penile vasculature.     

Cutaneous metastasis of primary appendicular osteosarcoma in a dog

A 6-year-old, neutered male Rottweiler was presented to the University of Illinois Veterinary Teaching Hospital because of a lytic bone lesion involving the distal portion of the right radius and possible pulmonary metastases on thoracic radiographs. Results of serum biochemical analysis were unremarkable. Aspiration and cytologic examination of the bone lesion indicated likely sarcoma with reactive bone. Cutaneous masses were found on the left thigh, interscapular region, and dorsal lumbar region, 4 weeks after initial presentation. Neoplastic spindle cells were found in aspirates from 2 of the masses. The neoplastic cells stained positive for alkaline phosphatase activity using cytochemistry. Re-evaluation of serum biochemical values at this time revealed a marked increase in alkaline phosphatase activity (413 U/L, reference interval 12-110 U/L) compared with the initial value (26 U/L). Due to progressive disease, the dog was euthanized and a necropsy was performed. Histologic findings included primary osteosarcoma of the distal portion of the right radius, with metastases in the lungs, spleen, left fourth and fifth ribs, soft tissue of the right medial thigh, and T1-T3/interscapular region. Cutaneous metastasis of primary appendicular osteosarcoma has been reported rarely in animals and humans. Increased serum alkaline phosphatase activity may be a potential indicator of poor prognosis for this neoplasm.     

Genitourinary rhabdomyosarcoma with systemic metastasis in a young dog

A 2-year-old intact female Golden Retriever presented due to rapidly progressing depression, ascites, dysuria, abdominal pain, and severe vaginal bleeding. At necropsy, the retroperitoneal space was expanded by multiple coalescing neoplastic nodules and the uterine wall was thickened with poorly defined neoplastic infiltrates. The urinary bladder was markedly thickened due to botryoid nodules exhibiting exophytic growth into the lumen. Metastases to lung, liver, kidney, and abdominal and thoracic lymph nodes were also noted. Microscopically, the genital tract and retroperitoneal masses were consistent with the alveolar subtype of rhabdomysarcoma, while the urinary bladder mass had characteristics of the embryonal subtype. Immunohistochemically, the neoplastic cells in all these tissue sites were intensely positive for desmin, sacromeric actin, and vimentin, while they were uniformly negative for cytokeratin and smooth muscle actin. Phosphotungstic acid hematoxylin stain revealed cross-striations in the cytoplasm of scattered neoplastic cells. Based on the gross findings, histopathology, and immunohistochemistry, genitourinary rhabdomyosarcoma with multisystemic metastases was made.     

Multiple joint metastasis of a transitional cell carcinoma in a dog

An 8‐year‐old castrated male hound mix was referred to the Purdue University Veterinary Teaching Hospital for severe lameness, pollakiuria, and dyschezia. On presentation, the dog was nonweight bearing on the right rear limb and the right carpus was diffusely swollen. Synovial fluid analysis from the right carpus revealed a population of epithelial cells displaying marked anisocytosis, anisokaryosis, multinucleation, and prominent, variably sized nucleoli. A metastatic carcinoma with presumed prostatic or urothelial origin was diagnosed based on cytomorphology. Subsequent cytologic evaluation of peripheral lymph nodes revealed the presence of a similar neoplastic population. The dog was euthanized and synovial fluid from both stifle joints, as well as impression smears of the prostate gland, were collected. Carcinoma cells were identified in each stifle joint and in the prostate gland. Immunocytochemistry was performed on synovial fluid smears from 2 of the joints (right stifle and right carpus) and on impression smears of the prostate gland. The neoplastic population in the joints and prostate gland showed strong immunoreactivity to uroplakin III, a urothelial marker, indicating metastasis of a transitional cell carcinoma to multiple joints. In addition, evidence for epithelial to mesenchymal transition was identified using cytokeratin, an epithelial marker, and vimentin, a mesenchymal marker. A necropsy was performed and histopathology confirmed the presence of metastatic transitional cell carcinoma in various tissues. This case illustrates the importance of considering metastatic disease when a patient is presented with severe lameness and joint pain, and the clinical utility of synovial fluid cytology for diagnosis of metastasis in these cases.     

Pancreatic beta-cell carcinoma with renal metastasis in a dog

Severe hypoglycemia associated with a metastatic pancreatic beta-cell carcinoma was found in an adult female American Eskimo dog. Metastatic tumor was found in the renal glomeruli as opposed to the more common hepatic metastatic site.     

Suspected uveal metastasis of a nail bed melanoma in a dog

A 13-year-old Golden Retriever was referred for evaluation of generalized corneal edema, dyscoria, and suspected glaucoma affecting the right eye. The dog exhibited no signs of systemic illness, but had a history of a melanoma of the nail bed of the first digit of the right hind limb, excised 1 year previously. Ophthalmologic examination revealed diffuse corneal edema, mild anterior uveitis, glaucoma and a mass within the right iris. Enucleation was performed and histopathologic evaluation of the globe revealed the iris to be infiltrated with an anaplastic melanoma, suspected to represent a metastasis of the original nail bed tumor.     

Carcinoma ex pleomorphic adenoma with sebaceous differentiation in the mandibular salivary gland of a dog

A carcinoma ex pleomorphic adenoma was diagnosed in the left mandibular salivary gland of an 8-year-old female spayed dog. The animal presented with a large nonpainful swelling in the left submandibular region. A computed tomography scan detected an irregularly enhancing soft tissue mass that was closely associated with the left external ear canal and extended to the left wing of the atlas. On surgical exploration, the mass was intimately associated with the left mandibular salivary gland. Both the mass and the adjacent gland were removed, and the diagnosis was determined by histopathology. The tumor was comprised of basaloid and low columnar epithelial cells, many glandular units formed by well-differentiated sebocytes, and multifocal regions of necrosis, mineralization, and hemorrhage. Salivary gland tumors with sebaceous differentiation are very rare in animals, with one previously reported case in a cat.