Cutaneous melanoma in a red-footed tortoise (Chelonoidis carbonaria)

There are few clinical reports of melanomas in reptiles. A 10-year-old male red-footed tortoise (Chelonoidis carbonaria) was referred to the Veterinary Hospital presenting with an ulcerated mass in the lateral aspect of the left pelvic limb. Radiographs demonstrated swelling and increased soft tissue density overlying the femur, tibia, and fibula, without bone involvement. Fine-needle aspiration cytology revealed innumerable round cells, with a defined cytoplasm filled with fine brown-black granules (melanin), which were considered well-differentiated melanocytes, suggesting a case of cutaneous melanoma. The mass was surgically removed. It was encapsulated and had an abundant blood supply. Histopathological examination revealed a well demarcated and encapsulated neoplastic proliferation of mesenchymal cells, with high cellularity and moderate fibrous stroma. Lymphangiectasia in the dermis adjacent to the tumor was also observed. Immunohistochemistry confirmed the diagnosis, with cells staining positive for Melan-A antibody being observed in neoplastic proliferation, adjacent dermis, inside lymphatic vessels, and invading the delimiting tumor's capsule. There was no evidence of local or systemic recurrence of the neoplasm over 500 days after removal. Chelonians can be affected by cutaneous melanomas. Surgical removal in this case was curative.     

Dysgerminoma in an eastern rosella (Platycercus eximius eximius)

This report describes a case of dysgerminoma in a 21-year-old eastern rosella (Platycercus eximius eximius) that presented with dyspnea and a severely distended coelom. The bird was euthanatized, and a large, left-sided coelomic mass was identified. Microscopically, the mass was composed of sheets and nests of round to polygonal neoplastic cells with lacy cytoplasm. The neoplastic cells were weakly positive for vimentin and c-kit but negative for pancytokeratin, AE1, and inhibin. On the basis of the histomorphology and immunoreactivity, the neoplasm was determined to be a dysgerminoma. The variability of histologic appearance and immunohistochemical staining of dysgerminomas in humans compared with veterinary species is discussed.     

B-cell conjunctival lymphoma in a cat

A bilateral conjunctival neoplasm was surgically removed from a 13-year-old Domestic Short-haired female cat and examined by histopathology. The neoplasm was infiltrative, nonencapsulated and composed of large sheets of densely packed, round to polygonal cells. Neoplastic cells were variably sized with scant to modest amounts of cytoplasm and oval to round nuclei. On immunohistochemistry the neoplastic cells stained positively for BLA.36 and negative for CD-3 antibodies. On the basis of histopathology and immunohistochemical findings, a diagnosis of conjunctival B-cell lymphoma was made. This is the first case with immunohistochemical characterization of conjunctival lymphoma in a cat.     

Subcutaneous hemangiosarcoma induced by a foreign body (steel staple) in a cat

An 8-year-old, female domestic shorthair cat was presented with a ventral abdominal subcutaneous mass. A radiograph showed that the center of the mass contained what appeared to be steel sutures, presumed to be from an ovariohysterectomy performed 7 years earlier. The excised mass was irregular and contained numerous pockets filled with friable necrotic material and hemorrhages that were dissected by fibrous connective tissue bands. Multiple tangled and fragmented pieces of steel staples were deeply embedded within the mass. Histologically, the mass was non-encapsulated, densely cellular, and infiltrative. Neoplastic cells lined caverns and channels and were factor VIII-positive by immunohistochemistry. The neoplastic cells were oval to round with granular cytoplasm and vesicular nucleus and exhibited moderate cellular and nuclear pleomorphism. A diagnosis of subcutaneous hemangiosarcoma was made. To our knowledge, this is the first report of foreign body associated hemangiosarcoma and the first case of steel staple associated neoplasm in domestic animals.     

Morphological, immunohistochemical, and ultrastructural findings in an embryonal rhabdomyosarcoma of a newborn thoroughbred foal

This study reports the rare case of a rhabdomyosarcoma in the shoulder of a newborn Thoroughbred foal. Histomorphologic, immunohistochemical, and ultrastructural investigations revealed an embryonal rhabdomyosarcoma with various differences: small round undifferentiated cells, rhabdomyoblast-like neoplastic cells, and spindle-shaped cells. Desmin expression appears in 30% of small round cells and in as many as 90% of spindle-shaped cells. Vimentin co-expression occurs in 90% of small round and spindle-shaped neoplastic cells but only in few (30%) rhabdomyoblast-like cells. Myoglobin was detected in 50% of the rhabdomyoblast-like cells and in 30% of spindle-shaped cells but not in small round neoplastic cells. This is the first time that rhabdomyosarcoma markers Myf-4 and Myo D1 were found in horses. Myf-4 and Myo D1 were expressed in about half of the neoplastic cells in immediately fixated specimens. Ultrastructural sarcoma-like packets and formations of primitive Z-bands, as well as a discontinuous basal lamina, were found and served to confirm our diagnosis.

Introduction

Malignant neoplasia of striated muscles in domestic animals represents uncommon findings.[1] Only single cases of rhabdomyosarcoma in horses of varying ages (2-19 years) and races (Quarter horses, Appaloosas, Thoroughbreds, ponies) were described. [2, 3, 4, 5, 6 and 7]In human medicine, histopathologically different partly overlapping types of rhabdomyosarcoma are distinguished, reflecting stages of differentiation and the morphology of the neoplastic cells[8 and 9]: (1) embryonal rhabdomyosarcoma (subtypes: spindle cell, small cell) and its botryoid variant; (2) alveolar (synonymous with juvenile) rhabdomyosarcoma; and (3) pleomorphic (synonymous with adult) rhabdomyosarcoma.In veterinary pathology, rhabdomyoma, rhabdomyosarcoma, and “embryonal rhabdomyosarcoma of the urinary bladder in dogs” are actually distinguished histopathologically.[10] But in older references the nomenclature of human medicine is used.In horses, alveolar rhabdomyosarcoma occur in the extremities.[2 and 5] Botryoid rhabdomyosarcomas were described in the equine uterus [4] and the urinary bladder. [7] Pleomorphic rhabdomyosarcomas are found in the tongue [6] and inside the thorax. [3]Differential diagnoses include fibrosarcoma, melanoma, anaplastic lymphosarcoma, and anaplastic carcinoma. Immunohistochemical[10, 11 and 12] and ultrastructural [13 and 14] investigations are helpful in confirming a diagnosis of rhabdomyosarcoma.Myo D1, Myf-3, and Myf-4 belong to a group of myogenic regulatory proteins whose expression determines commitment and differentiation of primitive mesenchymal cells into skeletal muscle.[15] Myf-3 protein, the human homologue of the murine Myo D1 gene product, is a factor capable of myogenic determination, whereas Myf-4, the human homologue of myogenin, is required downstream as a differentiating factor. [15]This paper reports morphologic, immunohistochemical, and ultrastructural findings of an unusual case of embryonal rhabdomyosarcoma in the right shoulder of a newborn foal.

Case history

A newborn Thoroughbred foal showed a swelling in the right shoulder. This thickening was growing fast and at the age of 3 months a carneous mass of 5 kg was removed surgically by the local veterinarian. A distal dehiscence of the suture appeared and the swelling recurred within the following 3 months.

Clinical findings

When the foal was presented to the veterinary clinic at the age of 6 months, it showed a good general condition and no evidence of lameness. The right shoulder laterally showed a thick firm swelling of 20 cm. (Fig 1). At the caudodistal edge, a 10 cm deep fistula was found and sonographic examination showed multiple cysts within the tissue. Cytologic examination of the cyst fluid revealed numerous neutrophils and some adipocytes. Additional clinical findings revealed mild blood leukocytosis.     

Fibrosarcoma with typical features of postinjection sarcoma at site of microchip implant in a dog: histologic and immunohistochemical study

A 9-year-old, male French Bulldog was examined for a subcutaneous mass located at the site of a microchip implant. Cytologic examination of the mass was suggestive of a malignant mesenchymal neoplasm. Histologically, the mass was confirmed as a high-grade infiltrative fibrosarcoma, with multifocal necrosis and peripheral lymphoid aggregates. By immunohistochemistry, the sample was investigated for vimentin, smooth-muscle actin (SMA), CD3, CD79alpha, and CD18. All the neoplastic cells were positive for vimentin. Scattered cells at the periphery of the lesion were also positive for SMA, highlighting a myofibroblastic phenotype. The lymphoid cells were positive for CD18 and CD3. No aluminum deposits were detected by the aurintricarboxylic acid method. A diagnosis of fibrosarcoma morphologically similar to feline postinjection sarcomas was made. Fibrosarcomas at the site of injections have been reported in dogs and ferrets. Furthermore, neoplastic growth at the site of microchip implant in dog and laboratory rodents has been described.     

Congenital branchial apparatus malformation in a Haflinger colt

Objective— To report the diagnosis and treatment of a branchial apparatus anomaly (BAA) associated with a mandibular malformation in a foal.
Design— Clinical report.
Animal— Haflinger foal.
Methods— A 6-day-old foal had a fluctuating cystic mass in the pharyngeal (throatlatch) region, which changed in appearance after ingestion of milk. Upper airway endoscopy and diagnostic imaging (ultrasonography, radiography, computed tomography) permitted identification of the anatomic location of a communicating tract between the lumen of the cystic mass and the pharynx. The mass was surgically removed and communication with the pharynx ligated. Histologic appearance of this mass was consistent with a branchial cyst or sinus. The mandibular malformation was managed conservatively.
Results— Surgical resection of a third branchial sinus resulted in an excellent functional and cosmetic outcome. There was no evidence of any mandibular deformity 2 years later.
Conclusion— BAA may induce secondary mandibular deformation in utero and may cause respiratory compromise postpartum. Careful surgical dissection and removal of BAA resulted in an excellent outcome.
Clinical Relevance— BAAs should be included in the differential diagnosis of a throatlatch region mass in equine neonates. Complete surgical excision is recommended and full recovery of any associated mandibular deformity may be anticipated without additional treatment in very young patients.     

Canine eyelid granular cell tumor: a report of eight cases

To describe a previously unreported neoplasm of the medial canthus and eyelid in dogs. Clinical and pathologic features of granular cell tumors in the dog were reviewed. Granular cell tumors, arising from the medial canthal eyelid of eight dogs, were identified from the archives of the Comparative Ocular Pathology Laboratory of Wisconsin (COPLOW). The affected dogs ranged in age from 5 to 12 years (mean of 9.25 years). Follow‐up information was available for seven of the eight cases. The clinical presentation included swollen hyperemic lids (4/8), ulcerated skin overlying the mass (2/8), and red conjunctiva (7/8). All eight of the cases had firm masses extending from the palpebral conjunctiva to the eyelid margin at the medial canthus. Histologically, the tissue was composed of a highly collagenous neoplastic growth. The neoplastic cells were oval to strap‐like cells with an oval bland appearing nucleus and abundant amounts of granular cytoplasm with very distinct cell boundaries. These granular cells were embedded in a dense collagen matrix. A PAS stain faintly highlighted the granular appearance of the neoplastic cells, which is a defining characteristic of this tumor. There was no recurrence in the seven cases available for follow‐up. Canine granular cell tumors of the medial canthus present clinically and histologically as a benign neoplasm. Granular cell tumors have a characteristic histological appearance. Granular cell tumors should be on the differential list for nodules of the medial canthus in dogs.     

Presumed post‐traumatic ocular chondrosarcoma with intrathoracic metastases in a cat

An indoor‐only, 5‐year‐old, spayed female domestic shorthair cat presented for an ophthalmic examination of the left eye. An intraocular tumor with secondary glaucoma and blindness was diagnosed; the globe was enucleated and sent for histopathological examination. Gross examination revealed a solid white mass filling the entire vitreous space and replacing the iris and ciliary body. The lens and retina appeared to be similarly replaced by the neoplasm. Histological examination revealed a complete loss of the internal ocular structures, with a ruptured capsule as the only remnant of the lens within an extensive malignant mesenchymal neoplastic cell proliferation. The cells were polygonal, with well‐defined cytoplasmic borders and abundant weakly basophilic cytoplasm, embedded within the islands of chondroid matrix. No neoplastic invasion of the sclera was apparent. The animal died 6 months after the enucleation due to respiratory distress. Gross examination revealed numerous firm, white to tan nodular masses with smooth to mildly irregular surfaces dispersed throughout the parietal pleura, thoracic surface of the diaphragm, tracheobronchial and mediastinal lymph nodes, pericardium, and lungs. On cross‐section, the neoplastic nodules were solid and variably translucent, resembling hyaline cartilage. Histologically, these nodules were similar to the neoplasm identified earlier in the left globe. Metastasis of post‐traumatic ocular chondrosarcoma has not yet been described in cats. This is therefore believed to be the first report of metastases of this type of neoplasm in cats. This case adds to the limited set of data on the outcome of this type of tumor.     

Spontaneous deciduosarcoma in a domestic rabbit (Oryctolagus cuniculus)

Deciduosarcoma is a rare, hormonally dependent neoplasm with features of malignancy, previously reported only in rabbits enrolled in chronic toxicology studies involving estrogens with or without progestins. An exploratory laparotomy was performed on a 6-year-old pet Dutch dwarf rabbit following palpation of a 6-cm-diameter abdominal mass. Grossly, the mass was fleshy and nodular, adhered to but not appearing to originate from the small intestine, with a smaller mass of similar appearance involving the uterus, and an effaced mesenteric lymph node. Histologically, the mass was characterized by spindloid cells and large epithelioid cells with abundant pale eosinophilic vacuolated cytoplasm and an infiltrative pattern of growth. Giant cells with large, bizarre, hyperchromatic nuclei were common. Cells were positive by immunohistochemistry for vimentin and progesterone and estrogen receptors and negative for pancytokeratin (AE1/AE3), cytokeratin 18, desmin, alpha-smooth muscle actin (SMA), and CD10. Based on histologic and immunohistochemical findings, a diagnosis of deciduosarcoma was made.     

Penetrating sclerokeratoplasty and autologous pinnal cartilage and conjunctival grafting to treat a large limbal melanoma in a dog

A four‐year‐old neutered male Labrador retriever presented to Portland Veterinary Specialists Ophthalmology Service for evaluation of a pigmented mass oculus sinister (OS) of approximately 4‐month duration. Complete ophthalmic examination revealed a large, pigmented, raised, well‐demarcated, epibulbar mass appearing to originate from the nasodorsal limbal region. The mass was smooth and roughly circular, extending approximately 4 mm into the sclera and 14 mm into the nasodorsal cornea. Gonioscopy directly under the mass was not possible due to mass size. The visible iridocorneal angle was normal. High‐resolution B‐scan ultrasound showed mass extension to Descemet's membrane and deep sclera, but no intraocular invasion. Penetrating sclerokeratoplasty was performed followed by autologous pinnal cartilage and conjunctival grafting to repair the corneoscleral defect (20 mm x 19 mm) and to restore globe integrity and function. Histopathology confirmed the mass to be a benign limbal melanoma with complete excision. The surgery site healed without complication, and the pinnal cartilage became fully incorporated into the globe. Twelve months postoperatively, the patient remains visual with a normal intraocular and fundic examination. The pinnal harvest site on the right ear healed without complication. To the authors’ knowledge, this is the first reported case of corneoscleral grafting using autologous pinnal cartilage. This may represent a viable alternative to other corneoscleral grafting procedures for large defects and is an attractive treatment option due to lack of host rejection, readily available source of donor cartilage, and provision of tectonic support to the globe.     

What is your diagnosis? Lingual mass in a dog

A 3.5-year-old female spayed Rat Terrier was presented for evaluation of a submucosal lingual mass. Fine-needle aspiration of the mass revealed a population of neoplastic cells composed predominantly of small, round cells and large, round to spindle-shaped cells, which occasionally had blunt cytoplasmic borders and multiple nuclei. The neoplastic cells had moderate to marked anisocytosis and anisokaryosis. The cytologic interpretation was malignant neoplasia, most likely sarcoma. Histopathologic examination of a biopsy specimen revealed an unencapsulated, poorly demarcated, moderately cellular neoplasm composed of individualized, infiltrative spindle cells. Elongate skeletal muscle cells with prominent, rectangular borders (strap cells) were observed. A morphologic diagnosis of rhabdomyosarcoma was made. Staining with phosphotungstic acid-hematoxylin revealed haphazardly arranged skeletal muscle cross-striations. Immunohistochemical staining results for vimentin, Myo D1, desmin, and myoglobin were positive, though staining intensity of tumor cells varied with the degree of differentiation. Using transmission electron microscopy, irregular, disorganized Z-bands were identified. Rhabdomyosarcomas are uncommon tumors in the dog, and rarely may involve the tongue or oral cavity. Cytologic evaluation of a rhabdomyosarcoma may reveal a pleomorphic population of cells and definitive diagnosis may require histologic examination, immunohistochemical staining, and electron microscopy.     

Dermal melanoma with schwannoma-like differentiation in a brown bullhead catfish (Ictalurus nebulosus).

A dermal melanoma with histologic similarities to mammalian melanocytic schwannomas was diagnosed in a wild-caught brown bullhead catfish (Ictalurus nebulosus). The diagnosis was based on cytologic, histopathologic, immunohistochemical, and ultrastructural findings. The neoplasm protruded from the cutaneous surface of the dorsal midline immediately caudal to the dorsal fin, was diffusely black and focally ulcerated, and was attached to the underlying skin by a broad-based stalk. Cytologically, the tumor was composed of a monomorphic population of melanophores, the melanin-producing and storing cells within the dermis and epidermis of fish that are partially responsible for rapid color changes. Histopathologic examination of the neoplasm revealed an unencapsulated, well-circumscribed, moderately cellular neoplasm composed of 2 distinct cell populations: spindle cells arranged in a "herringbone" pattern and numerous melanophores. The spindle cells had scant bipolar eosinophilic cytoplasm, with small centrally located vesicular nuclei; nucleoli were not seen. The histologic appearance was similar to that described for mammalian melanocytic schwannomas. Immunohistochemically, the spindle cells exhibited positive cytoplasmic staining for S-100 protein but were negative for vimentin, neurofilament protein, and glial fibrillary acidic protein. Ultrastructurally, the tumor consisted of neoplastic spindle cells with rudimentary cell junctions, actin bundles, and few melanosomes and melanophores with abundant intracytoplasmic melanosomes.     

Metastatic balloon cell melanoma in a dog

Background: Balloon cell melanoma is a rare variant of amelanotic melanoma that is difficult to differentiate from sebaceous cell carcinoma, liposarcoma, and other clear cell neoplasms without immunohistochemistry or ultrastructural evidence of melanin or melanosomes. Objective: The purpose of this report was to describe the clinical, cytologic, histologic, immunohistochemical, and ultrastructural findings in a dog with metastatic balloon cell melanoma. Methods: A 6‐year‐old female Golden Retriever was evaluated for a white, flocculent infiltrate in the anterior chamber of the left eye and an enlarged left prescapular lymph node. Cytologic evaluation of the eye and lymph node were performed following aqueocentesis and fine‐needle aspiration, respectively. The affected lymph node was examined histologically and stained for cytokeratin, vimentin, S‐100, and Melan A. Following euthanasia a necropsy was performed and samples of the affected lymph node were examined by electron microscopy. Results: Cytologic examination of the lymph node and aqueocentesis sample revealed round neoplastic cells that had abundant clear vacuolated cytoplasm. A tentative diagnosis of metastatic sebaceous cell carcinoma or clear cell neoplasm was made. Histologically, the affected lymph node had similar polygonal clear cells arranged in sheets and packets divided by delicate fibrovascular stroma. Immunohistochemical staining of the cells was negative for cytokeratin but positive for vimentin, weakly positive for S‐100, and strongly positive for Melan A. At necropsy, metastatic lesions were identified in the diaphragm, heart, lung, kidneys, left eye, prescapular and sublumbar lymph nodes, and multiple skin sites. Ultrastructural examination of neoplastic lymph nodes revealed many membrane‐bound vacuoles, myelinlike figures, and rare melanosomes. Conclusion: Immunohistochemical staining and ultrastructural features of the neoplastic cells supported a diagnosis of metastatic balloon cell melanoma.     

Thyroid follicular adenocarcinoma in a ferret

A 5-year-old male castrated ferret was presented to the Washington State University College of Veterinary Medicine for evaluation of progressive hair loss and a large, rapidly growing ventral neck mass. The patient had been diagnosed previously with an insulinoma, which was managed medically. Fine-needle aspirates of the neck mass were performed. The cytologic results were most consistent with epithelial neoplasia, likely a carcinoma; thyroid origin was considered likely based on tumor location and cell morphology. The tumor grew rapidly, and the owners elected euthanasia 1 week after examination. At necropsy, a circumscribed, ovoid mass disrupted the right cervical musculature next to the right lobe of the thyroid gland. Histopathologic evaluation revealed an infiltrative mass consisting of cuboidal cells arranged in solid sheets and irregular follicles enclosing colloid. The cells were large, with prominent nucleoli, and had a high mitotic rate. The histopathologic diagnosis was consistent with thyroid follicular adenocarcinoma. Immunochemical findings confirmed thyroglobulin production by neoplastic cells, but to a lesser extent than in normal ferret thyroid tissue. To our knowledge, this is the first case of thyroid follicular adenocarcinoma to be reported in a ferret, with only 1 other case of thyroid carcinoma, a C-cell carcinoma, described previously.     

Cerebral granular cell tumor (myoblastoma) in a dog: case report and literature review.

An infiltrative granular cell tumor (myoblastoma) occurred in the superficial parieto-occipital cortex of an ataxic 12-year-old dog. The neoplasm was characterized by cells with numerous small PAS-positive, diastase-resistant cytoplasmic granules. The neoplasm also had numerous cells with large globular PAS-positive bodies (angulate bodies). Ultrastructurally, the neoplastic cells were characterized by numerous homogenous electron-dense, sharply bounded granules and large pleomorphic, indistinctly bounded granules. The angulate bodies were composed of 8- to 10-nm fibrils, a few of which formed parallel arrays or tubule-like structures. This represents the first report of a granular cell tumor in the central nervous system of the dog.     

Metastatic Tumor in Pregnancy: Placental Germ Cell Tumor With Metastasis to the Foal

A placental mass was observed in an otherwise-healthy Quarter Horse mare; subsequently, the mare's 52-day-old foal was examined because of hind limb ataxia, urinary incontinence, and raised lesions of the distal limbs. Clinical and biochemical findings were supportive of liver disease and lumbosacral injury. Ultrasonographic evaluation of the abdomen suggested a liver mass, which was confirmed with computed tomography (CT) and determined to be neoplastic via histopathologic evaluation of a liver biopsy sample. Initial histopathology suggested a germ cell tumor. Regions of lysis affecting both femurs and third metacarpal bones and a complete oblique sagittal fracture through the body of the first sacral vertebra were present on CT. Supportive care was provided until CT confirmation of diffuse hepatic neoplasia and vertebral fracture. Necropsy revealed a large multinodular mass within the liver and a pathologic fracture of the first sacral vertebral body. Histopathologic comparison between neoplastic cells examined from the placenta and foal confirmed metastases of a germ cell tumor. Placental tumors are rare in all species; however, when noted in horses, clinicians should be aware of the possibility of metastatic spread to the foal.     

Cerebral high-grade astrocytoma (glioblastoma) in a cat

A cerebral tumour was found in the right frontal lobe of a 7-year-old female mongrel cat. The mass showed infiltrative growth and caused deformation of the corpus callosum. Histopathologically, the tumour cells showed anaplasia, pleomorphism and mitotic figures. Necrosis and vascular proliferation were prominent. The neoplastic cells surrounded areas of necrosis, but as an indistinct pseudopalisade formation. Immunohistochemically, low numbers of tumour cells labelled positively for anti-glial fibrillary acidic protein and anti-S100 protein. Electron microscopically, the majority of tumour cells had no filaments and cytoplasmic processes, but the differentiated cells presented cytoplasmic filaments and glycogen granules. Based on these findings, the tumour was diagnosed as cerebral high-grade astrocytoma, glioblastoma.     

A case of conjunctival melanoma in a cat

Since 1985, 5 cases of feline conjunctival melanoma have been reported in the literature. Information on feline conjunctival melanoma epidemiological features, localizations, macroscopic features and histological features is limited. We are describing the clinical, histopathologic features and outcomes in a cat that presented clinically with a slow developing dark brown mass located under the upper eyelid of the left eye. Pertinent literature is reviewed; and the recognizable clinical features and treatment are discussed. The mass was surgically resected. Despite its size, the lesion was easily separated from underlying tissues, making possible a macroscopic complete resection that left intact the adjacent conjunctiva. The tumour histological examination has showed a pigmented melanoma lacking encapsulation, but presenting a clear zone delimiting the lesion. It was exclusively composed of epithelioid cells, and presented mild cellular anaplasia and weak mitotic activity. These features allowed it to be classified as a quite differentiated melanoma with few signs of potential malignancy. In accordance with these histologic features, no recurrence has been registered 34 months after surgery. Thus, a favorable outcome is now reported for two out of six cases of conjunctival melanoma in the cat. This report also confirms the predilection for this neoplasm to arise from the bulbar conjunctiva.     

Glomus tumor of the liver in a cow

An 11-year-old Holstein-Friesian cow exhibited anorexia and jaundice. A large mass was found in the liver during necropsy. Macroscopically, the mass was composed of dark red multilobular tissue and a centrally located abscess, which was connected to the hepatic duct. Histologically, the mass consisted of proliferation of small neoplastic cells and was demarcated from the hepatic parenchyma by a thick region of granulation tissue. The neoplastic cells were predominantly arranged in solid sheets, but they also formed blood-filled cancellous structures, and proliferating foci were seen around blood vessels. Periodic acid-Schiff reaction demonstrated that a fine basement membrane-like structure surrounded the neoplastic cells. Immunohistochemically, the neoplastic cells were positive for vimentin and alpha smooth muscle actin and negative for cytokeratin, factor VIII-related antigen, chromogranin and desmin. Based on its histopathological features, the hepatic neoplasm was diagnosed as a primary glomus tumor. This is the first report about a primary glomus tumor of the liver in a cow.