Malignant peripheral nerve sheath tumour with divergent epithelioid differentiation in a cat.

Divergent differentiation, mainly towards various subsets of mesenchymal cells, is encountered sporadically in human malignant peripheral nerve sheath tumours (MPNSTs) but this is the first report of epithelioid components within this neoplasm in a cat. An 8-year-old, spayed female Domestic Shorthaired cat was presented for surgical removal of a subcutaneous mass on the right flank. Morphological and immunohistochemical analysis revealed a malignant neoplasm with spindloid cells intermixed with an epithelioid component that had squamous differentiation. There was intense immunolabelling of vimentin, S100 protein, neuron-specific enolase, laminin and glial fibrillary acidic protein in the spindloid cell component and for cytokeratin (CK) AE1/AE3 and CK5/6 in the epithelial elements. Melanoma-associated antigen, desmin, α-smooth muscle actin, CD18, CD31, ionized calcium binding adapter molecule-1 and CK8/18 were not expressed, which helped differentiate the tumour from other feline spindloid cell neoplasms. These features are characteristic of divergent epithelioid differentiation of MPNST.

Malignant peripheral nerve sheath tumor in the kidney of a dog.

A 12-year-old castrated male poodle presented with vomiting and diarrhea. Ultrasonography and computed tomography revealed a protruding mass at the caudal pole of the left kidney. Grossly, the poorly circumscribed abnormal mass was 1.6 × 1.8 × 1.9 cm in size and had multifocal dark-red foci. Microscopically, it was composed of densely or loosely packed variable-sized short spindle or ovoid cells. These neoplastic cells showed high pleomorphism, mitotic figures, and invasive tendency to the adjacent tissue. Immunohistochemically, the neoplastic spindle cells expressed vimentin, S100, neuron-specific enolase, nerve growth factor receptor, and laminin. Therefore, the mass was diagnosed as a malignant peripheral nerve sheath tumor (MPNST). To our knowledge, this is the first report of primary renal MPNST in a dog.

A retrospective study on subcutaneous malignant peripheral nerve sheath tumors in 14 domestic rabbits (Oryctolagus cuniculus) treated surgically between 2008 and 2021.

A retrospective study involving 14 pet rabbits histopathologically diagnosed with malignant peripheral nerve sheath tumors (MPNSTs) was conducted. The age at diagnosis was 4-12 years, with a median age of 8.6 years. All rabbits had solid subcutaneous tumor masses in varied locations. Surgical excision of the tumors was performed in all cases. Recurrence was observed in 10 cases (71%), and postoperative metastasis to the lung was suspected in 4 cases (29%). The postoperative mean and median survival times were 11 months and 9 months, respectively. Hence, MPNSTs should be considered in the differential diagnosis for subcutaneous masses in rabbits and it is essential to inform the owners of the potentially high recurrence and metastasis rates.

Cardiac tumor comprising a malignant peripheral nerve sheath tumor and spontaneous atrial osseous metaplasia in a sheep.

Primary cardiac tumors in animals are very rare. The purpose of this report was to describe the first case of a cardiac tumor comprising a malignant peripheral nerve sheath tumor and spontaneous atrial osseous metaplasia in a Corriedale sheep. Histologically, the tumor in the bilateral atrial pericardium consisted of dense cellular components comprising tumor cells and a sparse cellular area, and non-neoplastic mature bone tissue. The tumor cells were spindle-shaped, round, or polygonal, and proliferating, with fascicular, storiform, palisading, and sheet patterns. Immunohistochemically, the tumor cells were positive for vimentin, S-100, occasionally positive for myeline basic protein, glial fibrillary acidic protein, neurofilament, neuron specific enolase, and neuron growth factor receptor suggesting that they originated from the nervous system. On the basis of these findings, the final diagnosis was a malignant peripheral nerve sheath tumor and spontaneous atrial osseous metaplasia.

Surgical and oncologic outcomes in dogs with malignant peripheral nerve sheath tumours arising from the brachial or lumbosacral plexus.

Malignant peripheral nerve sheath tumours (MPNST) of a plexus nerve or nerve root cause significant morbidity and present a treatment challenge. The surgical approach can be complex and information is lacking on outcomes. The objective of this study was to describe surgical complication rates and oncologic outcomes for canine MPNST of the brachial or lumbosacral plexus. Dogs treated for a naïve MPNST with amputation/hemipelvectomy with or without a laminectomy were retrospectively analysed. Oncologic outcomes were disease free interval (DFI), overall survival (OS), and 1- and 2-year survival rates. Thirty dogs were included. The surgery performed was amputation alone in 17 cases (57%), and amputation/hemipelvectomy with laminectomy in 13 cases (43%). Four dogs (13%) had an intraoperative complication, while 11 dogs (37%) had postoperative complications. Histologic margins were reported as R0 in 12 dogs (40%), R1 in 12 dogs (40%), and R2 in five dogs (17%). No association was found between histologic grade and margin nor extent of surgical approach and margin. Thirteen dogs (46%) had recurrence. The median DFI was 511 days (95% CI: 140-882 days). The median disease specific OST was 570 days (95% CI: 467-673 days) with 1- and 2-year survival rates of 82% and 22% respectively. No variables were significantly associated with recurrence, DFI, or disease specific OST. These data show surgical treatment of plexus MPNST was associated with a high intra- and postoperative complication rate but relatively good disease outcomes. This information can guide clinicians in surgical risk management and owner communication regarding realistic outcomes and complications.

A rare case of cecal malignant peripheral nerve sheath tumor in a dog.

A 12-year-old mixed-breed dog presented with a 2-month history of abdominal distension. Radiographic examination, abdominal ultrasonography, and computed tomography revealed a mass in the cecum (15.0 × 11.9 × 4.5 cm). The cecal mass was surgically removed and examined histopathologically. Immunohistochemically, the neoplastic cells expressed S-100 and neuron specific enolase but not α-smooth muscle actin and CD117 (c-kit). These histologic and immunohistochemical features indicated that the mass was consistent with a malignant peripheral nerve sheath tumor (MPNST). In dogs, most MPNSTs arise from the brachial plexus, spinal nerve root, and skin of the extremities. However, gastrointestinal MPNSTs in dogs have not been described previously. To the best of our knowledge, this is the first report to describe cecal MPNST in a dog.

Malignant Peripheral Nerve Sheath Tumour in a Seba's Short-Tailed Bat (Carollia perspicillata).

There are few reports of tumours in bats, despite the fact that members of the Chiroptera order include 22.4% of all currently known mammal species. We now describe a case of malignant peripheral nerve sheath tumour (MPNST) in an adult female Seba's short-tailed bat (Carollia perspicillata) from a private zoo in Switzerland. The macroscopical and histological findings indicated that the MPNST originated from a dorsal spinal nerve root sheath in the lumbar region and metastasized to the spleen. Immunohistochemical labelling for glial fibrillary acid protein, S100 protein, neuron specific enolase and synaptophysin was negative. The cytoplasm of a few neoplastic cells labelled for smooth muscle actin and desmin. To our knowledge, this is the first report of a PNST in a member of the Chiroptera order.

Primary malignant peripheral nerve sheath tumors arising from the spinal canal invading the abdominal cavity in a dog.

A 9-year-old neutered male Wire Fox Terrier presented with an 1-month history of hindlimb paresis. Magnetic resonance imaging revealed a contrast-enhanced mass at the level of the L2 vertebral canal. The dog became paraplegic with no deep perception of the hindlimbs, and the mass was surgically removed. The histopathological diagnosis was of a malignant peripheral nerve sheath tumor (MPNST). The dog suffered a relapse of right hindlimb ataxia at 225 days after the surgery. The dog died 434 days after the surgery. Necropsy found a large mass in the abdominal cavity invading from the L2-nerve. This is the first report of MPNST invading the abdominal cavity through the nerve root.

A case of a malignant peripheral nerve sheath tumor in a guinea pig.

Here, we describe the clinical and histopathological characteristics of a malignant peripheral nerve sheath tumor (MPNST) extending from the dorsal subcutis to the periphery of the spine in a female guinea pig aged 3 years 7 months. The patient presented with pleural and blood-like pericardial effusion and died. The tumor had invaded the spine and the surrounding muscles and had grown in hypercellular and hypocellular arrangements of round, broad-spindle, and elongated-spindle cells. We observed a fascicular growth pattern, nuclear palisading, and perivascular accumulations of cells that responded positively to anti-S100, sox10, and CD56 antibodies. This is the first report of a MPSNT in a guinea pig.

[The nerve root syndrome in small animals - A review focussing on pathophysiology and therapy in the dog]. / Das Nervenwurzelsyndrom beim Kleintier.

A large variety of etiologies is considered to be the cause of nerve root syndrome in dogs. Lateralized disc herniation, foraminal stenosis and malignant as well as benign nerve sheath tumors are some of the most important triggers described. The clinical signs of a nerve root syndrome are characterized by monoparesis in combination with progressive lameness, which may be accompanied by an elevation of the affected limb. Although the problem is well known among clinicians, there is no review article in the veterinary literature that specifically covers the subject of "nerve root syndrome in small animals". Mostly, this is merely mentioned as a symptom of its potential etiologies, as the so-called "nerve root sign" or "nerve root signature". In the pathophysiology of nerve root compression or irritation, a number of biomechanical and biochemical factors play a role. These occur individually or in combination and may lead to the same changes. The pathophysiology of the syndrome seems to focus around changes in microcirculation. These microcirculation disorders not only lead to pathomorphological changes such as edema formation, demyelination and axon death, but also initiate a cascade of reactions at the site of damage as well as in the central nervous tissue. This leads to the release of various neuropeptides, modulation of nerve excitability and impulse transmission. Different pathomechanisms therefore often lead to a uniform damage pattern, which makes it difficult to point out the original triggering factors. The body's response to these factors determines whether a nerve root syndrome actually develops or not. The treatment of the cause, if found, and an individual and multimodal pain therapy seem to be the most successful therapeutic approaches for nerve root syndrome in dogs.

Central nervous system metastasis of an intradural malignant peripheral nerve sheath tumor in a dog.

An 8-yr-old French Bulldog was presented with a non-ambulatory tetraparesis. Magnetic resonance showed an intradurally located mass at the level of the right second cervical nerve root. The mass was surgically removed and the dog was ambulatory within 4 d. A 10-mo post-surgical imaging follow-up revealed a recurrence of the primary mass and another intradural/intramedullary mass at the level of the first thoracic vertebral body. Overall histological features were suggestive of malignant peripheral nerve sheath tumor (MPNST) for both masses. Immunohistochemistry was found weak but diffusely positive for S-100 and neurono-specific enolase for both masses. A diagnosis of primary MPNST for the cervical mass and of metastasis for the thoracic mass was made, possibly disseminated via the subarachnoidal space. To our knowledge, the central nervous system metastasis of MPNSTs has not previously been reported in dogs. The clinician should be aware that these tumors, albeit rarely, can metastasize to the central nervous system.

Malignant Cutaneous Peripheral Nerve Sheath Tumour with Rhabdomyosarcomatous Differentiation (Triton Tumour) in a Domestic Cat.

Divergent differentiation is encountered frequently within human malignant peripheral nerve sheath tumours (MPNSTs). The new component is often a rhabdomyosarcoma, but in animals this specific form of divergent differentiation within MPNSTs has only been reported once (in a dog). Incisional wedge biopsy of a locally extensive, ventral abdominal wall mass, which extended from the dermis to the subcutis, from a 12-year-old female domestic shorthaired cat, was performed. The tissue was examined with routine haematoxylin and eosin staining and immunohistochemical methods. A malignant neoplasm with spindle and polygonal cell components and progression towards a rhabdomyosarcomatous phenotype was observed. Both neoplastic cell populations exhibited strong expression of vimentin and there was multifocal expression of S100 and desmin. There was strong cytoplasmic labelling for α-sarcomeric actin and muscle actin and weak labelling for myoglobin within the cells positive for desmin. There was multifocal positive nuclear labelling for myogenin. Glial fibrillary acidic protein, α-smooth muscle actin, microphthalmia-associated transcription factor and melanoma antigen recognized by T cells were not expressed. Microscopical features, aided by immunohistochemistry, identified a MPNST with progression towards a rhabdomyosarcomatous phenotype, a so-called 'triton tumour'. A Schwann cell component could account for the divergent patterns of growth, given the plasticity of the neural crest. Nerve sheath tumours have been reported in the skin and subcutis of cats and are a differential diagnosis of feline cutaneous spindle cell neoplasms.

Malignant peripheral nerve sheath tumor originating from the adrenal gland in a dog.

A large abdominal mass was found in a dog. Histopathologically, the surface of the mass was covered with compressed adrenal gland tissue. The neoplastic cells showed typical features of malignant peripheral nerve sheath tumor (MPNST), including Antoni type A and type B pattern, and nuclear palisading. Immunohistochemically, these cells were positive for S100 protein, nerve growth factor receptor, nestin and claudin-1. The dog was euthanized because of the developing multiple metastatic lesions. The metastatic cells showed quite similar histopathological and immunohistochemical features as those in the original tumor. Although MPNST can develop at many body sites, this is the first report of MPNST originating from the adrenal gland in a dog.

Case report and immunohistochemical study of a malignant peripheral nerve sheath tumor in a dog / Relato de caso e estudo imuno-histoquímico de tumor maligno da bainha do nervo periférico em um cão

Malignant peripheral nerve sheath tumor is rare and rarely reported in dogs. The term neurofibroma/sarcoma is classically used when the tumor is composed of Schawann and perineural cells. This work describes the clinical, histopathological, and immunohistochemical case of a subcutaneous malignant peripheral nerve sheath tumor, most likely a malignant neurofibroma located in the pelvic member of a Rottweiler dog. Histopathological features and immunohistochemical analysis corroborated the diagnosis, showing positivity for S-100 protein, vimentin, and CD57, and was useful to distinguish this type of neoplasm from other malignancies of similar morphologies.(AU)

O tumor maligno da bainha do nervo periférico é raro e pouco descrito em cães. Classicamente, o termo "neurofibroma/sarcoma" é empregado quando o tumor é composto por células de Schwann e células perineurais. Neste relato são descritos os achados clínicos, histopatológicos e imuno-histoquímicos de um caso de tumor maligno da bainha do nervo periférico, provavelmente neurofibrossarcoma, localizado no subcutâneo do membro pélvico de um cão da raça Rottweiler. Os achados histopatológicos associados às observações imuno-histoquímicas contribuíram para o diagnóstico, sendo observada positividade para proteína S-100, vimentina e CD57, permitindo a diferenciação da neoplasia em questão de outros tumores malignos com características morfológicas similares.(AU)

Ulnar malignant peripheral nerve sheath tumour diagnosis in a mixed-breed dog as a model to study human: histologic, immunohistochemical, and clinicopathologic study.

Canine Malignant Peripheral Nerve Sheath Tumors (MPNSTs) are uncommonly reported in the ulnar, since they are underestimated relative to the more common spindle cell tumours of soft tissue. In dogs, MPNST accounts for 27% of nervous system tumours. In man, MPNST represents 5-10% of all soft tissue sarcomas and is often associated with neurofibromatosis type 1 (NF-1).An 8-year-old, 9 kg, female mixed-breed dog with a subcutaneous mass on the upper right side of the ulnar region was presented to the small animal research and teaching hospital of Tehran University. The dog was anorexic with general weakness. The mass (7 × 4 cm) was removed surgically and processed routinely. Microscopically, the mass was composed of highly cellular areas with a homogeneous population of round or spindle cells, high cellular pleomorphism, high mitotic index and various morphologic patterns. Furthermore, spindle cells arranged in densely or loosely sweeping fascicles, interlacing whorls, or storiform patterns together with wavy cytoplasm, nuclear palisades, and round cells were arranged in sheets or cords with a meshwork of intratumoral nerve fibers. In addition, in this case the presence of neoplastic cells within the blood vessels was observed. Immunohistochemically, tumor was positive for vimentin and S-100 protein. The histopathologic features coupled with the S-100 and vimentin immunoreactivity led to a diagnosis of malignant neurofibroma.To the best of our knowledge, primary ulnar MPNST has not been reported in animals. This is the first documentation of an ulnar malignant peripheral nerve sheath tumour in a dog. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1310907815984587.

Molecular characteristics and pathogenicity of an avian leukosis virus isolated from avian neurofibrosarcoma.

Peripheral nerve sheath tumors (PNSTs) are rare in chickens and their etiology remains to be elucidated. In this study, a naturally occurring PNST in a Japanese native fowl (Gallus gallus domesticus) was pathologically examined and the strain of avian leukosis virus (ALV) isolated from the neoplasm was characterized by molecular biological analysis. The fowl presented with a firm subcutaneous mass in the neck. The mass, connected to the adjacent spinal cord (C9-14), was microscopically composed of highly cellular tissue of spindle cells arranged in interlacing bundles, streams, and palisading patterns with Verocay bodies and less cellular tissue with abundant collagen. Immunohistochemically, neoplastic cells were divided into two types: perineurial cells positive for vimentin, glucose transporter 1 (GLUT1), and claudin1; and Schwann cells positive for vimentin, occasionally positive for S-100 alpha/beta but negative for GLUT1. Based on these findings, a diagnosis of neurofibrosarcoma was made. The complete nucleotide sequence of an ALV strain, CTS_5371, isolated from the neoplasm was determined and phylogenetic analysis indicated that the strain was a novel recombinant virus from avian leukosis/sarcoma viruses previously reported. Additionally, experimental infection revealed that CTS_5371 induced the proliferation of Schwann cells and perineurial cells. These results suggest that this ALV strain has the ability to induce PNSTs in chickens.

Gross and histopathological characteristics of two lipomas and a neurofibrosarcoma detected in aquacultured southern bluefin tuna, Thunnus maccoyii (Castelnau), in South Australia.

Three visible lesions were examined from two specimens of southern bluefin tuna. The lesions were examined grossly and two were identified as lipomas, the third bore similarities to a schwannoma. Histopathology confirmed that two consisted of mature adipocytes consistent with a diagnosis of lipoma. The third lesion consisted of spindle cells in Antoni A and B patterns and was tentatively diagnosed as a malignant schwannoma. Immunohistochemistry identified both S100 and glial fibrillary acid protein expression within the lesion, which, together with the histopathological appearance, is consistent with a diagnosis of neurofibrosarcoma.

Primary and secondary heart tumours in dogs and cats.

Primary and secondary neoplasms of the canine and feline heart are uncommon. During a 2-year period, 83 dogs suffering from primary cardiac (n=11), extracardiac benign (n=6) or malignant (n=66) tumours and 30 cats with primary cardiac (n=1) or extracardiac (n=29) malignant tumours were examined. Echocardiography revealed four cases of primary cardiac neoplasms in dogs, but secondary heart tumours were not detected. After necropsy, tissue samples from the heart and tumours were examined histologically and immunohistochemically. In dogs, primary neoplasms included seven haemangiosarcomas, two chemodectomas, one rhabdomyosarcoma, and one neurofibrosarcoma. In 24 of 66 dogs examined, metastases of extracardiac neoplasms were found in the heart (15 carcinomas, six malignant lymphomas, three haemangiosarcomas). In cats, one case of primary haemangiosarcoma of the pericardium and five cases of secondary cardiac tumours (two malignant lymphomas, three carcinomas) occurred. Cardiac neoplasms in cats were not identified clinically but were detected by detailed gross sectioning of the heart (n=2) or histopathological examinations (n=3). This study showed an unexpectedly high number (36%) of dogs with cardiac metastases.

Comparison of fine-needle aspiration and surgical-tissue biopsy in the diagnosis of canine brain tumors.

OBJECTIVE: To compare the diagnoses obtained using fine-needle aspiration (FNA) and surgical-tissue biopsy of focal cerebral masses with the histologic diagnoses obtained via necropsy. STUDY DESIGN: A prospective case series. SAMPLE POPULATION: Ten client-owned adult dogs of various breeds. All dogs had clinical signs of cerebral disease and had a focal brain mass identified using magnetic resonance imaging; all were eventually euthanatized. METHODS: Immediately after euthanasia, the brains were removed en bloc from the cranial cavity. FNAs were obtained from each mass using a 22-gauge hypodermic needle and a 12-mL syringe. Cytologic preparations were made from each aspirate. A 14-gauge Tru-cut biopsy needle was used to obtain a core tissue sample from each mass. The biopsy specimens were fixed in 10% buffered formalin and submitted for histologic evaluation. The brains were similarly fixed and stained. Six-micrometer-thick transverse sections of the brain were examined microscopically. RESULTS: Neoplasia was confirmed in all dogs histologically in the 6-microm transverse sections. Four meningiomas, 2 astrocytomas, 2 oligodendrogliomas, 1 pituitary adenocarcinoma, and 1 neurofibrosarcoma were identified. FNA correctly identified all of the masses as neoplastic. Cytologic diagnoses correlated with the histologic interpretation in 5 of the masses (50%). Tru-cut biopsy specimens identified all 10 masses as neoplastic; in 9 of the 10 (90%), the diagnosis correlated with the histologic diagnosis. CONCLUSIONS AND CLINICAL RELEVANCE: FNA is a sensitive method that can be used to determine the presence of neoplasia in the brain, but is not as definitive as the Tru-cut biopsy in determining the specific type of cerebral neoplasm.