A collision tumor consisting of granular cell tumor and adenocarcinoma in the uterus of an aged djungarian hamster

A neoplastic nodular lesion consisting of an admixture of granular cell tumor and adenocarcinoma was found in the uterus of a 26-month-old Djungarian hamster. Neoplastic cells of the uterine adenocarcinoma showed an epithelial nature in their growth patterns and by cytokeratin-immunopositive reaction, exhibiting nuclear pleomorphism. The granular cells had an abundant amount of fine granular eosinophilic cytoplasm and eccentric or central nuclei with no nuclear atypia; the granular structures were positive for periodic acid-Schiff with diastase resistance and were confirmed as lysosomes/autophagosomes by electron microscopy; immunohistochemically, the cells reacted to desmin, vimentin and α-smooth muscle actin and negatively for neurogenic, histiocyte/macrophage or epithelial markers, indicating smooth muscle origin. Because these tumors were generated from different cell origins, a diagnosis of collision tumor was made.     

Myxosarcomas associated with avian leukosis virus subgroup A infection in fancy breed chickens

Formalin-fixed suspect tumors were submitted to the Poultry Diagnostic and Research Center at the University of Georgia (Athens, GA) for diagnosis. Samples were from fancy breed chickens with a history of increased tumor prevalence in both hens and roosters. Microscopically, in all the samples, there were neoplastic proliferations of spindle-shaped cells. The matrix surrounding tumor cells stained positively with Alcian blue at pH 2.5, but neoplastic cells did not stain with periodic acid-Schiff. Immunohistochemistry stains were positive for vimentin and neuron-specific enolase and negative for desmin, smooth muscle actin, and S-100 protein. Tumors were determined to be myxosarcomas. All samples were positive for PCR targeting the gp85 avian leukosis virus (ALV) envelope protein. However, analysis of the predicted amino acid sequences in the envelope gene from three separate samples showed high similarity between them and to ALV subgroup A.     

Nasal oncocytoma in a domestic shorthair cat

An oncocytoma was diagnosed in the nasal cavity of a 12-year-old Domestic Shorthair cat who presented with periocular swelling and sneezing. Histologic examination from biopsy material revealed monomorphic sheets, anastomosing cords, tubules, and acini composed of large polygonal to oval cells that contained abundant finely granular eosinophilic cytoplasm. No vascular or lymphatic invasions were noted. Histochemical stains revealed positive staining of tumor cells with periodic acid-Schiff (PAS) (before and after diastase digestion) and phosphotungstic acid-hematoxylin. Immunohistochemical evaluation of the tumor cells demonstrated positive staining for cytokeratin and negative staining for vimentin, desmin, S-100, glial fibrillar acidic protein, and neuronal specific enolase. Ultrastructurally, the tumor cells contained large numbers of mitochondria within their cytoplasm, which confirmed a diagnosis of oncocytoma.     

Immunohistochemical and ultrastructural investigation of granular cell tumours in dog, cat, and horse.

Six canine, one feline and one equine granular cell tumours (GCTs) were investigated electron microscopically and immunohistochemically. The tumours were tested for reactivity with monoclonal antibodies against vimentin and desmin and with polyclonal antibodies against cytokeratin, S-100 protein, glial fibrillary acidic protein (GFAP) and neuron specific enolase (NSE). All GCTs were characterized by their PAS positive cytoplasmic granules in light microscopy, which in electron microscopy appeared as lysosome-like granules. In each case two canine GCTs were stained by the antibody against cytokeratin, vimentin and S-100 protein. Cells of the equine GCT showed reactivity with the antiserum against S-100 protein. In the feline GCT no reactivity with any of the antibodies tested was observed. These differences of the immunohistochemical reactions of GCTs suggest a nonuniform histogenesis of GCTs in domestic animals. The reactivity of the tumour cells with the antiserum against NSE is discussed.     

Multicentric benign peripheral nerve sheath tumors in two related bearded dragons, Pogona vitticeps

Multiple subcutaneous masses from two sibling bearded dragons were removed. Nodules were well demarcated, restricted to the subcutis, and soft, white to yellow, resembling adipose tissue. Histologically, the masses were composed of short interlacing streams and bundles of spindle cells, with regions of vague nuclear palisading. Two of the tumors contained a subpopulation of polygonal cells with abundant periodic acid-Schiff (PAS)-positive cytoplasmic granules. Neoplastic cells were immunohistochemically positive for S100 and neuron-specific enolase (NSE) but negative for desmin and smooth muscle actin. Electron microscopy and reticulin stains demonstrated a continuous basal lamina separating intertwining cells. Histologic, ultrastructural, and immunohistochemical features were consistent with a peripheral nerve sheath origin. At 1 year postexcision, local reoccurrence of a single incompletely excised mass from the left shoulder was noted.     

Iridociliary epithelial tumors in 100 dogs and 17 cats: a morphological study

The morphological features of iridociliary epithelial tumors in 100 dogs and 17 cats were reviewed. Twenty-seven cases were in either Golden Retrievers or Labrador Retrievers. Affected globes were stained for light microscopy with alcian blue, periodic acid Schiff (PAS) and hematoxylin and eosin stains. Selected tissues were examined by immunohistochemistry for vimentin, desmin, cytokeratin, S-100, neuron-specific enolase (NSE), and glial fibrillary acid protein (GFAP). The presence or absence of hyaluronic acid was recorded by staining with alcian blue before and after digestion of the tissue with hyaluronidase. Canine tumors were divided into papillary and solid tumors based on the pattern of growth. Twenty-eight of 57 papillary tumors exhibited invasive behavior including eight of the 57 which showed infiltration of the sclera. Twenty-nine of 43 solid tumors were invasive including 13 of 43 with scleral invasion. Tumors with scleral invasion were designated adenocarcinoma. Tumors of both types could be pigmented or nonpigmented and often contained smooth basement membranes reminiscent of the inner membrane of the nonpigmented ciliary body epithelial cell. All of the feline tumors were nonpigmented and 14 of 16 feline tumors were solid and two of the tumors were papillary. Eighteen of 20 canine tumors and three of four feline tumors stained positive for vimentin. Cytokeratin stain was positive only in a few of the highly aggressive tumors. The finding of pigmented epithelial cells, thick, smooth basement membrane structures, positive staining for vimentin, S-100, and NSE as well as hyaluronic acid deposition were considered to be features which define iridociliary epithelial tumors in dogs. The positive staining for vimentin and NSE are highly specific markers which help to characterize iridociliary epithelium and distinguish this tumor from metastatic epithelial tumors. The finding of solid nonpigmented tumors with small epithelial cells packeted by thin PAS-positive membranes staining positive for vimentin were considered significant features defining iridociliary epithelial tumors in cats. Follow-up information on survival and cause of death was obtained on 43 canine cases and only two feline cases. The average follow-up interval in dogs was 25 months and only two dogs died with lesions that could have been due to metastasis although neither was confirmed. We concluded that neither iridociliary adenomas nor adenocarcinomas is likely to metastasize.     

Granular cell variants in a rat schwannoma. Evidence of neurogenic origin of granular cell tumor (myoblastoma).

A large, intraabdominal rat schwannoma had numerous granule-containing cells cytologically identical to cells of granular cell tumor (myoblastoma). The small eosinophilic granules stained positively by the periodic acid-Schiff (PAS) reaction, with intensity not reduced by diastase pretreatment. Granules stained positively with the Tibor Pap silver impregnation for reticulin and by electron microscopy were identical to myoblastoma cell granules. The nuclei of granular cells were morphologically identical to those of the neoplastic Schwann cells. The granular cells were in numerous foci within the tumor, frequently were seen in mitosis, and possessed an extremely variable volume of cytoplasm. They seemed to evolve from neoplastic Schwann cells. Cells with only a narrow perinuclear rim of granular cytoplasm were of the same size and general configuration as adjacent neoplastic Schwann cells, while cells with increasing volumes of granular cytoplasm were increasingly swollen and round. One area of the tumor was composed almost entirely of such large cells and was histologically identical to classic granular cell tumor.     

Cytologic, histologic, and immunohistochemical features of lingual liposarcoma in a dog

A 9-year-old female spayed mixed-breed dog was presented to the referring veterinarian with a history of decreased appetite and difficulty with prehension and swallowing because of a firm oval mass in the tongue. On cytologic evaluation of a fine-needle aspirate of the mass there were numerous round to polygonal cells organized individually or in loose clusters with rare branching capillaries. The cells had eosinophilic granular cytoplasm, round to oval nuclei, and occasionally indistinct borders. The cytologic diagnosis was granular cell tumor (GCT) of the tongue. Impression smears of a biopsy sample of the lingual mass contained similar eosinophilic granular cells with variable numbers of clear vacuoles in the background, numerous perivascular arrangements, and occasional lipoblasts, suggestive of liposarcoma. On histologic examination the tumor was composed of numerous lipocytes with rare foci of round eosinophilic granular cells without evidence of vacuolation; occasionally, atypical mitotic figures were seen. Immunohistochemically, the cells were uniformly negative for periodic acid-Schiff and did not express smooth muscle actin, desmin, or cytokeratin but were immunoreactive for vimentin and S100. A diagnosis of well-differentiated liposarcoma was made on the basis of morphologic and immunohistochemical results. Eosinophilic granular cells may be a component of well-differentiated liposarcoma and are not limited to GCT. Liposarcoma should be considered in the differential diagnoses of lingual tumors in the dog when cytological evaluation reveals eosinophilic granular cells consistent with GCT.     

Primary ureteral giant cell sarcoma in a Pomeranian

An 8-year-old male neutered Pomeranian dog was presented to the Veterinary Teaching Hospital at Oregon State University for surgical treatment of hydronephrosis of the left kidney and a left cranial abdominal mass. A primary ureteral mass was found during exploratory surgery, and the mass was resected and ureteral anastomosis was performed. Cytologic evaluation of the mass revealed 3 distinct cell populations, including a large number of multinucleated giant cells, a moderate number of thin spindle-shaped cells, and cohesive clusters of transitional epithelial cells. The cytologic diagnosis was giant cell sarcoma. The diagnosis was confirmed by histologic examination, and immunohistochemical staining was performed. The spindle-shaped cells and multinucleated giant cells were both immunoreactive for vimentin and spindle-shaped cells for S-100. Tumor cells did not express wide-spectrum cytokeratin, broad-spectrum muscle actin, smooth muscle actin, sarcomeric actin, desmin, BLA36, Mac 387, synaptophysin, neuron-specific enolase, glial fibrillary acid protein, or von Willebrand factor. These findings are most consistent with an anaplastic sarcoma with giant cells. This is the first case report of a primary ureteral giant cell sarcoma in a dog.     

Canine cutaneous clear cell adnexal carcinoma: histopathology, immunohistochemistry, and biologic behavior of 26 cases.

Thirty tumors including 27 distinctive cutaneous neoplasms and 3 metastatic tumors from 26 dogs were collected from diagnostic submissions to 3 laboratories. Characteristic histopathologic features included location in the subcutis or dermis (or both); lobular, nodular, and nest-like architecture; and a component of epithelioid cells with clear cytoplasm. Additional features present in most cases included follicular dermal papilla-like structures, low mitotic index, nuclear pleomorphism, necrosis, and mineralization. Cytoplasmic periodic acid Schiff-positivity, which was abolished by pretreatment with diastase, indicated the presence of glycogen in all cases. The oil red O stain did not demonstrate cytoplasmic lipid. Melanin granules, accentuated by the Fontana-Masson method, were observed infrequently. A sparsely cellular mucinous stroma and stromal cartilaginous differentiation were uncommon. By immunohistochemistry, neoplastic cells stained positively for cytokeratin (29 of 29), vimentin (28 of 28), S-100 protein (24 of 29), and melan A (8 of 12); results were negative for smooth muscle actin and calponin in all cases. Clinical follow-up information was obtained on all 26 dogs. One tumor recurred, 1 metastasized to a regional lymph node, and 1 metastasized to regional lymph nodes twice. In another case, possible pulmonary metastasis was noted radiographically. The findings are consistent with a poorly differentiated, low-grade, adnexal carcinoma of the skin. Similar canine cutaneous neoplasms have been reported as "clear-cell hidradenocarcinoma" and "follicular stem cell carcinoma." The authors propose the designation "cutaneous clear cell adnexal carcinoma."     

Morphologic, cytochemical staining, and ultrastructural characteristics of blood cells from eastern diamondback rattlesnakes (Crotalus adamanteus)

OBJECTIVE: To evaluate light microscopic, cytochemical, and ultrastructural characteristics of blood cells from eastern diamondback rattlesnakes. ANIMALS: 10 healthy snakes. PROCEDURE: Various stains, including Wright-Giemsa, benzidine peroxidase, Sudan black B, chloroacetate esterase, alpha-naphthyl butyrate esterase, acid phosphatase, leukocyte alkaline phosphatase, periodic acid-Schiff with diastase, and toluidine blue, were used to stain leukocytes differentially on multiple blood smears. Electron microscopy also was performed. RESULTS: Lymphocytes were the most commonly observed leukocyte and could be distinguished from thrombocytes, using periodic acid-Schiff stain with diastase. Azurophils also were commonly observed; their granules stained with peroxidase. Eosinophils were not identified; however, 2 morphologic variations of heterophils were seen in the blood of all snakes and were considered the same cell type at different stages of cytoplasmic granule development. Heterophil granules were better preserved, using a one-step Wright-Giemsa method that did not require alcohol fixation prior to staining. Degranulated heterophils were observed in all preparations. CONCLUSIONS: Most leukocytes of eastern diamondback rattlesnakes can be identified easily on Wright-Giemsa-stained preparations. However, hematologic stains that do not require alcohol fixing prior to staining may be preferred for leukocyte evaluation in certain reptiles. A limited degree of heterophil maturation may continue in the blood of healthy snakes. This, along with degranulation of heterophils, may result in a variable staining pattern in this cell type, regardless of the stain used. CLINICAL RELEVANCE: Results provide baseline data for use in hematologic testing in diagnosis of disease and monitoring of treatment of sick or injured snakes.     

Symptomatic granular cell tumor involving the pituitary gland in a dog: a case report and review of the literature

A granular cell tumor involving the pituitary gland, optic chiasm and ventral pyriform lobes was discovered in a 12-year-old Labrador Retriever. Clinical signs included acute blindness, seizures, ataxia, weakness, and behavioral changes. The diagnosis was established by histopathologic and ultrastructural examination of neoplastic tissues collected at necropsy. Granular cell tumors involving the central nervous system are well documented in humans but rarely have been described in dogs. The location of the neoplasm and the clinical symptoms seen in this dog closely parallel those of a rare syndrome in humans commonly described as symptomatic parasellar or pituitary granular cell tumors. The cell of origin for these tumors is still highly debated, and attempts to characterize human granular cell tumors through immunohistochemistry have produced conflicting results. An immunohistochemical profile of this neoplasm revealed focal positive staining for vimentin with a lack of staining for neuron-specific enolase, glial fibrillary acidic protein, S-100, and synaptophysin. All neoplastic cells were strongly positive with the periodic acid-Schiff reaction.     

Metastatic iridociliary adenocarcinoma in a labrador retriever

An enucleated left eye from a 15-year-old female spayed Labrador Retriever was received by the Comparative Ocular Pathology Laboratory of Wisconsin (COPLOW) for histopathologic evaluation. Routine histologic preparation included staining with hematoxylin and eosin, and with alcian blue periodic acid-Schiff (PAS). At necropsy 9 months later, all grossly abnormal tissues (ipsilateral orbit and lung) were submitted to the COPLOW for histopathologic evaluation. Histopathologic evaluation of the globe revealed extensive invasion of the uvea and sclera by a pleomorphic cell population that formed disorganized cords and exhibited PAS-positive basement membrane material. Necropsy revealed a morphologically similar tumor in the ipsilateral orbit and lung. On immunohistochemical examination, the intraocular tumor stained diffusely immunopositive for vimentin, S-100, and neuron-specific enolase and multifocally, sparsely immunopositive for cytokeratin AE1/AE3. The orbital and thoracic tumors stained positively for vimentin but negatively for cytokeratin AE1/AE3. There are few reports of canine metastatic iridociliary adenocarcinoma in the literature; this is the first with immunohistochemical analysis.     

Cytology of a mass on the meningeal surface of the left brain in a dog

An 11-year-old neutered male Labrador Retriever presented to Tufts University School of Veterinary Medicine for a 2-week history of seizures and altered behavior. Magnetic resonance imaging (MRI) revealed a homogeneously enhancing mass involving the surface of the left temporal, parietal, and occipital lobes of the brain, causing secondary hydrocephalus. Cytology samples obtained during rostrotentorial craniectomy contained abundant amorphous pink material suggestive of neuropil, scattered leukocytes, capillary fragments, large polyhedral nerve cell bodies, and other smaller cells with pale blue cytoplasm that occasionally were vacuolated and contained fine eosinophilic granules. The cytologic diagnosis was neoplasia, possibly meningioma. Ninety days after surgery the patient was euthanized after MRI results confirmed regrowth of the tumor. Histologic samples of the meningeal lesion collected at necropsy consisted of sheets and nests of loosely packed, large polygonal cells that compressed the brain parenchyma. The cytoplasm was eosinophilic and slightly granular, whereas nuclei were dense and eccentric. Neoplastic cells stained positive for S-100 protein, periodic acid-Schiff, and were partially diastase resistant. Vimentin staining was negative. Ubiquitin staining was light but diffusely positive. Ultrastructural features of the neoplastic cells included numerous secondary lysosomes and irregular pleomorphic nuclei. The final diagnosis was meningeal granular cell tumor. This case documents the cytologic and histologic features of an uncommon type of meningeal tumor.     

Dermal intravascular leiomyosarcoma in a cat

A 10-year-old female spayed domestic shorthaired cat presented with a subcutaneous tumor between the first and second phalanges of the left hind foot. Six months after excision, a similar tumor occurred on the medial aspect of the third phalanx of the same limb. Histologically, both tumors consisted of solid masses of spindle and round cells, many of which grew within endothelial-lined vessels. Tumor cells stained positively for smooth muscle actin and vimentin, but were negative for cytokeratin, S-100, desmin, synaptophysin, factor VIII-related antigen, and neuron-specific enolase. The diagnosis was dermal intravascular leiomyosarcoma.     

Glomangioma in the Prepuce of a Dog

A case of preputial glomangioma in an 8-year-old Springer Spaniel dog is reported. The dog presented a solitary nodular mass, approximately 3.5 x 5.2 cm in diameter, located on the lateral wall of the prepuce at the base of the penis. Histologically, the excised tumour mass consisted of proliferating round epithelioid cells arranged in a cordon-like structure around small blood vessels. The neoplastic cells were positive for alpha smooth muscle actin and negative for cytokeratin, desmin, S-100 protein and neurone-specific enolase. Based on these pathologic features, the tumour was diagnosed as glomangioma, a neoplasm extremely rare in dogs. To our knowledge, this is the first report of preputial glomangioma in the dog.     

Bilateral renal oncocytoma in a Greyhound dog

A bilateral, locally invasive renal oncocytoma was diagnosed in a 10-year-old spayed female Greyhound dog. The diagnosis was based on positive staining of the tumor with the periodic acid-Schiff reaction prior to diastase treatment, on the immunohistochemical expression of cytoplasmic cytokeratin, and on the prominence of mitochondria in the tumor cells.     

Feline intraocular tumors may arise from transformation of lens epithelium

Feline ocular sarcomas are malignant intraocular neoplasms that are frequently associated with a history of ocular trauma. They usually present as fibrosarcomas, but some have both epithelial and mesenchymal features. The purpose of this study was to determine the cell of origin of a subset of feline intraocular sarcomas that display a mixed epithelial-mesenchymal phenotype, with elaboration of basement membrane-type matrix. We examined the morphology and histochemical and immunohistochemical phenotypes of nine feline intraocular sarcomas. Immunohistochemistry and in situ hybridization were performed to detect expression of crystallin alpha A. In addition, tumors were examined for expression of vimentin, cytokeratin, smooth muscle actin, desmin, melan A, neural cell adhesion molecule, S-100, glial fibrillary acidic protein, nerve growth factor receptor, and collagen type IV. Animals ranged from 7 to 17 years of age--no breed or sex predilection for tumor occurrence was present. Tumors were characterized by mixed epithelial and mesenchymal phenotypes, both of which elaborated basement membrane-type material and expressed vimentin highly. On the basis of collagen type IV and crystallin alpha A immunopositivity, we established that three of nine tumors were of lens epithelial origin. Expression of desmin and smooth muscle actin identified one tumor as a leiomyosarcoma. The remainder were undifferentiated sarcomas of myofibroblastic origin. This is the first report of lens epithelial neoplasia in clinical material from any species. The history and morphologic features of feline ocular sarcomas are reminiscent of feline vaccine-induced sarcomas. These tumors may share pathophysiologic similarities unique to this species.