Immunohistochemical analysis of equine pulmonary granular cell tumours

Intracranial Granular Cell Tumours in Three Dogs: Atypical Magnetic Resonance Imaging Features and Immunohistochemical Study

Intracranial granular cell tumours (GCT) are uncommon neoplasms of uncertain cellular origin that are rarely reported in dogs. This case series describes three aged dogs that presented with neurological signs in which magnetic resonance (MR) imaging revealed plaquelike extra-axial lesions that were hypointense on T2-weighted (T2w) images. The surgical biopsy of the lesions and necropsies were followed by histochemical characterisation with periodic acid-Schiff (PAS) staining and immunohistochemistry with ubiquitin, S-100, and SOX-10 to elucidate the cellular origin. The immunohistochemical study indicated that these intracranial GCTs were not of Schwann cell origin. In conclusion, GCTs should be considered a differential diagnosis of intracranial, extra-axial hypointense brain lesions on T2w MR images.

Biofluid Markers of Equine Neurological Disorders Reviewed From Human Perspectives

Neurological disorders (NDs) are often fatal to horses. Thus, symptoms of equine NDs commonly indicate euthanasia. Current diagnostic approaches for equine NDs is based on clinical signs, differential diagnoses, analysis of cerebrospinal fluid (CSF), assessment of histopathological lesions, and imaging. However, advances in biofluid biomarkers in the diagnosis of human neurological diseases can potentially be applied to equine NDs. In this review, we described the established human blood and CSF neurobiomarkers that could potentially be used to diagnose equine NDs.

Granular Cell Tumor in a Horse: Multifocal Pulmonary Distribution and Evidence of Autophagy in Tumorigenesis

Granular cell tumor (GCT) is a soft tissue neoplasm characterized by abundant intracellular eosinophilic granules. The majority of GCTs are benign, although some display malignant behavior. Furthermore, GCTs may mimic other neoplasms. The clinical course and biology of GCTs are poorly understood. Regarding the histogenesis of GCT, a Schwann cell origin is currently favored in light of immunohistochemical and ultrastructural analyses. However, based on literature data, some of the primitive GCTs show non-neural origin; therefore, the histogenesis of this tumor has remained enigmatic. Granular cell tumors can arise in almost any location of the body and typically present as solitary lesions. This study illustrates equine primary GCT with multifocal pulmonary distribution. The presence of GCT in the respiratory tract becomes a diagnostic challenge on initial presentation. The morphologic details of this case are presented. Immunohistochemical evaluation confirmed the neuronal origin of equine GCT and the relation of intracytoplasmic granules formation to an autophagy phenomenon. Most of the discussion is related to GCT nature to help characterize molecular aspects associated with the biological behavior of this tumor and its heterogeneity.

ERBB3: A potential serum biomarker for early detection and therapeutic target for devil facial tumour 1 (DFT1)

Devil Facial Tumour 1 (DFT1) is one of two transmissible neoplasms of Tasmanian devils (Sarcophilus harrisii) predominantly affecting their facial regions. DFT1's cellular origin is that of Schwann cell lineage where lesions are evident macroscopically late in the disease. Conversely, the pre-clinical timeframe from cellular transmission to appearance of DFT1 remains uncertain demonstrating the importance of an effective pre-clinical biomarker. We show that ERBB3, a marker expressed normally by the developing neural crest and Schwann cells, is immunohistohemically expressed by DFT1, therefore the potential of ERBB3 as a biomarker was explored. Under the hypothesis that serum ERBB3 levels may increase as DFT1 invades local and distant tissues our pilot study determined serum ERBB3 levels in normal Tasmanian devils and Tasmanian devils with DFT1. Compared to the baseline serum ERBB3 levels in unaffected Tasmanian devils, Tasmanian devils with DFT1 showed significant elevation of serum ERBB3 levels. Interestingly Tasmanian devils with cutaneous lymphoma (CL) also showed elevation of serum ERBB3 levels when compared to the baseline serum levels of Tasmanian devils without DFT1. Thus, elevated serum ERBB3 levels in otherwise healthy looking devils could predict possible DFT1 or CL in captive or wild devil populations and would have implications on the management, welfare and survival of Tasmanian devils. ERBB3 is also a therapeutic target and therefore the potential exists to consider modes of administration that may eradicate DFT1 from the wild.

Equine skin tumours in 20 horses resembling three variants of human melanocytic naevi

Melanocytic tumours are important in horses, especially grey horses. Intradermal common melanocytic naevi, cellular blue naevi and combined cellular blue naevi are subgroups of human melanocytic tumours, which have not been reported in horses. In this study, we describe 20 horses with skin tumours similar to these naevi of humans. These tumours represented individual skin masses in male and female horses of different breeds. Tumours resembling human intradermal common melanocytic naevi were noted in 12 horses aged between 2 and 17 years. Seven horses aged between 4 and 15 years developed cutaneous lesions similar to human cellular blue naevi. A combined cellular blue naevus-like tumour was diagnosed in a 20-year-old horse. All tumour types formed expansile, well-demarcated, non-encapsulated, symmetrical masses. Tumours similar to intradermal common melanocytic naevi were composed of nests of round and spindeloid neoplastic cells, often embedded in myxomatous stroma. Lesions resembling cellular blue naevi were formed by intradermal bundles of ovoid to elongated cells separated by collagen fibres. The combined cellular blue naevus-like tumour resembled human cellular blue naevus with in addition, an overlying junctional common melanocytic naevus. Neoplastic cells in all groups contained varying amounts of melanin pigment and were immunopositive for S100. These equine skin tumours differ from the commonly recognized equine melanocytic tumours by their cytomorphological features, random location and the absence of an increased tumour frequency in grey horses. The resemblance of these tumours to three distinct subgroups of human naevi expands the complexity of equine proliferative cutaneous melanocytic lesions.

Granular Cell Tumour Affecting the Left Vocal Cord in a Dog

Granular cell tumours (GCTs) have been described in human vocal cords, but not in those of the dog. A single polyp in the left vocal cord, associated with laryngeal oedema and monolateral hyperplasia of the tonsil, was observed endoscopically in a 6-year-old male dog. Cytologically, the mass was characterized by well-defined polygonal cells, with granular cytoplasm and an eccentric nucleus. Histologically, the mass showed sheets of globoid to polygonal cells, filled with numerous diastase-resistant, periodic acid-Schiff-positive granules, and scanty stroma. Ultrastructurally, the granules were represented by heterogeneous lysosomes of variable size, suggesting a diagnosis of GCT. As reported in man, hyperplasia of the laryngeal and tonsillar epithelium and the presence of foci of pearl-like epithelial cells, mimicking invasive squamous cell carcinoma, were observed. Immunohistochemical examination revealed labelling of neoplastic cells for S-100 protein, CD68, collagen IV, and, focally, for glial fibrillary acidic protein, neuron-specific enolase and vimentin. These findings suggested a Schwann cell origin of the GCT.

Lower airway diseases of the adult horse

Lower airway problems of the adult horse are commonly encountered by the practitioner. Particularly susceptible populations include horses transported for any significant distance and young horses grouped together for training and/or competition. This article presents some of the commonly encountered problems of this patient population, including bacterial pneumonia/pleuropneumonia and influenza, and some uncommon ones, including pulmonary edema, pneumothorax/hemothorax, and acuterespiratory distress syndrome. Information is presented that should allow the practitioner to diagnose these problems accurately and initiate rational treatment plans.