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

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.

Enhancer reprogramming in PRC2-deficient malignant peripheral nerve sheath tumors induces a targetable de-differentiated state

Malignant peripheral nerve sheath tumors (MPNSTs) are soft tissue sarcomas that frequently harbor genetic alterations in polycomb repressor complex 2 (PRC2) components-SUZ12 and EED. Here, we show that PRC2 loss confers a dedifferentiated early neural-crest phenotype which is exclusive to PRC2-mutant MPNSTs and not a feature of neurofibromas. Neural crest phenotype in PRC2 mutant MPNSTs was validated via cross-species comparative analysis using spontaneous and transgenic MPNST models. Systematic chromatin state profiling of the MPNST cells showed extensive epigenomic reprogramming or chromatin states associated with PRC2 loss and identified gains of active enhancer states/super-enhancers on early neural crest regulators in PRC2-mutant conditions around genomic loci that harbored repressed/poised states in PRC2-WT MPNST cells. Consistently, inverse correlation between H3K27me3 loss and H3K27Ac gain was noted in MPNSTs. Epigenetic editing experiments established functional roles for enhancer gains on DLX5-a key regulator of neural crest phenotype. Consistently, blockade of enhancer activity by bromodomain inhibitors specifically suppressed this neural crest phenotype and tumor burden in PRC2-mutant PDXs. Together, these findings reveal accumulation of dedifferentiated neural crest like state in PRC2-mutant MPNSTs that can be targeted by enhancer blockade.

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.

Volumetric Modulated Arc (Radio) Therapy in Pets Treatment: The "La Cittadina Fondazione" Experience

Volumetric Modulated Arc Therapy (VMAT) is a modern technique, widely used in human radiotherapy, which allows a high dose to be delivered to tumor volumes and low doses to the surrounding organs at risk (OAR). Veterinary clinics takes advantage of this feature due to the small target volumes and distances between the target and the OAR. Sparing the OAR permits dose escalation, and hypofractionation regimens reduce the number of treatment sessions with a simpler manageability in the veterinary field. Multimodal volumes definition is mandatory for the small volumes involved and a positioning device precisely reproducible with a setup confirmation is needed before each session for avoiding missing the target. Additionally, the elaborate treatment plan must pursue hard constraints and objectives, and its feasibility must be evaluated with a per patient quality control. The aim of this work is to report results with regard to brain meningiomas and gliomas, trigeminal nerve tumors, brachial plexus tumors, adrenal tumors with vascular invasion and rabbit thymomas, in comparison with literature to determine if VMAT is a safe and viable alternative to surgery or chemotherapy alone, or as an adjuvant therapy in pets.

Frameless stereotactic volumetric modulated arc radiotherapy of brachial plexus tumours in dogs: 10 cases

OBJECTIVE

Treatment of canine peripheral nerve sheath tumours (PNSTs) is challenging and prognosis after surgical resection is considered poor. The aim of this study was to evaluate the feasibility and effectiveness of stereotactic radiotherapy (RT) of these tumours.

METHODS

10 dogs with clinical symptoms and MRI findings consistent with PNSTs of the brachial plexus, branches and nerve roots were treated with linear accelerator-based volumetric-modulated arc radiotherapy (VMAT) with a dose of 35 Gy/5 fractions. Clinical and MRI follow-up examinations were planned and radiotoxicity and survival times were investigated.

RESULTS

Tumours involved the plexus and proximal nerves in three dogs, the plexus, proximal nerves and nerve roots in five dogs and the nerve roots and proximal nerves in two dogs. Partial response and partial or complete reductions of neurological deficits were observed in all the treated dogs. Local recurrence was observed in 9/10 of treated dogs. No symptom directly referable to radiotoxicity was observed. Mean overall survival of 371 ± 30 days [95% confidence interval (CI) of (315-427)] and mean progression-free survival of 240 ± 30 days (95% CI of 188-291) from this work are comparable with surgical literature data regarding the plexus and proximal nerve localization, but are superior in comparison with nerve root localization.

CONCLUSION

VMAT can be a safe and viable alternative to surgery in cases of canine brachial plexus PNSTs involving the proximal nerves and nerve roots. Advances in knowledge: To our knowledge, this is the first prospective observational clinical study regarding VMAT stereotactic RT treatment for canine brachial plexus PNSTs and suggests that VMAT may achieve at least similar clinical outcome than surgery in a safer way.

Unclassified sarcomas: a study to improve classification in a cohort of Golden Retriever dogs

Morphologically, canine soft-tissue sarcomas (STSs) resemble human STSs. In humans, proper classification of STSs is considered essential to improve insight in the biology of these tumors, and to optimize diagnosis and therapy. To date, there is a paucity of data published on the significance of detailed classification of STSs in the dog. We revised a cohort (n = 110) of proliferative lesions obtained from a study in Golden Retrievers that were considered "soft tissue sarcoma, not otherwise specified or of uncertain subtype" in order to optimize the diagnoses of these lesions. The criteria according to the veterinary WHO classification, recent veterinary literature, and the WHO classification for humans were applied. Revision was initially based on morphologic characteristics of hematoxylin and eosin-stained histologic sections of the neoplasms. If considered necessary (n = 76), additional immunohistochemistry was applied to aid characterization. The diagnosis of STS was confirmed in 75 neoplasms (68%). Of this group, diagnosis of a specific subtype of the STSs was possible in 58 neoplasms. Seven neoplasms had morphologic characteristics that were suggestive for sarcoma subtypes only described in the WHO classification for humans. Seventeen neoplasms remained "unclassified STSs." Thirty-one lesions (28%) were diagnosed "neoplasm, not being STS." Four lesions (4%) were considered nonneoplastic. Because incorrect classification of a tumor could lead to inappropriate therapeutic intervention and prognostication, the results of our study clearly illustrate the importance of revision and further diagnosis of "unclassified STSs" in dogs.

Cellular and biological evaluation and diagnostic immunohistochemistry of cytokeratin 15/19 expression in distinguishing cutaneous basal cell carcinoma

Recent studies have investigated the expression of proliferative markers, but little is known about the expression of cytokeratin 15 and 19 in different histological subtypes of basal cell carcinoma (BCC). We conducted cellular, biological, clinicopathological and immunohistochemical analysis on the manifestations of 8 BCC by hematoxylin and eosin stain (H&E) staining and immunohistochemistry and reviewed relevant literature. Microscopically, the tumor cells were multiple remarkable foci of epidermolytic hyperkeratosis with large pleomorphic nuclei and scant cytoplasm together with peripheral palisading and forming solid nests. Furthermore, the most tumors were composed of highly cellular areas with a homogenous population of round, ovoid and spindle cells, hyperchromatic nuclei, high cellular pleomorphism, high mitotic index and various morphologic patterns. Moreover, the tumors displayed an invasive growth, with positive expression of Cytokeratin 19 (CK19) and negative expression of CK15. Our study revealed that the expression of CK19 was associated with progression and invasion in cases with BCC and immunohistochemistry is indispensable in distinguishing this tumor from other types of cutaneous carcinoma. To our best knowledge, it may be a considerable biomarker to assess invasiveness of cutaneous-surface BCC and to guide clinical management of such tumors.

Malignant peripheral nerve sheath tumor of the third eyelid in a 3-year-old Rhodesian Ridgeback

A 3-year-old Rhodesian Ridgeback was presented with conjunctivitis, enlargement of the third eyelid and a dorsotemporal deviation of the right eye. A mass within the third eyelid was detected and excised. The histopathologic examination showed a malignant peripheral nerve sheath tumor, which most likely is a neurofibrosarcoma based on immunohistochemistry.

Cyto-histopathological and outcome features of the prepuce squamous cell carcinoma of a mixed breed dog

Abstract

Virtual Slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/5748771971272873

Clinico-histopathologic and outcome features of cutaneous infundibular keratinizing acanthoma: a case report and literature review

The infundibular keratinizing acanthoma (IKA) is a rare epithelial benign keratin-containing neoplasm of hair follicles. The purpose of this study was to evaluate the defining histopathologic architecture of IKA. A typical IKA consisted of a keratin-filled crypt in the dermis and subcutis that opened to the skin surface. Most of this tumor occurred on the back, neck, head, and the shoulders. Microscopically, the dermal nodules were focally contiguous in both the dermis and subcutis. Furthermore, most histological lesions are consistent with a simple or multiloculated cyst filled with keratin and lined by a wall of stratified squamous epithelium; keratin appears as a concentric lamellar mass, with a keratotic pearly aspect. Histological examination of the cutaneous lesions revealed that the growths were comprised of IKA. IKA of man and dog were compared, and it was concluded that although they are similar in many respects, they are not identical entities. To the best of our knowledge, this is the first report on the prevalence of IKAs among the population of owned dogs in Iran.

Histopathological features of bone regeneration in a canine segmental ulnar defect model

Background

Today, finding an ideal biomaterial to treat the large bone defects, delayed unions and non-unions remains a challenge for orthopaedic surgeions and researchers. Several studies have been carried out on the subject of bone regeneration, each having its own advantages. The present study has been designed in vivo to evaluate the effects of cellular auto-transplantation of tail vertebrae on healing of experimental critical bone defect in a dog model.

Methods

Six indigenous breeds of dog with 32 ± 3.6 kg average weight from both sexes (5 males and 1 female) received bilateral critical-sized ulnar segmental defects. After determining the health condition, divided to 2 groups: The Group I were kept as control I (n = 1) while in Group II (experimental group; n = 5) bioactive bone implants were inserted. The defects were implanted with either autogeneic coccygeal bone grafts in dogs with 3-4 cm diaphyseal defects in the ulna. Defects were stabilized with internal plate fixation, and the control defects were not stabilized. Animals were euthanized at 16 weeks and analyzed by histopathology.

Results

Histological evaluation of this new bone at sixteen weeks postoperatively revealed primarily lamellar bone, with the formation of new cortices and normal-appearing marrow elements. And also reformation cortical compartment and reconstitution of marrow space were observed at the graft-host interface together with graft resorption and necrosis responses. Finally, our data were consistent with the osteoconducting function of the tail autograft.

Conclusions

Our results suggested that the tail vertebrae autograft seemed to be a new source of autogenous cortical bone in order to supporting segmental long bone defects in dogs. Furthermore, cellular autotransplantation was found to be a successful replacement for the tail vertebrae allograft bone at 3-4 cm segmental defects in the canine mid- ulna. Clinical application using graft expanders or bone autotransplantation should be used carefully and requires further investigation.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2028232688119271.

Metastatic ovarian papillary cystadenocarcinoma to the small intestine serous surface: report of a case of high-grade histopathologic malignancy

Ovarian cystadenocarcinoma is characterized by marked heterogeneity and may be composed of an admixture of histologic growth patterns, including acinar, papillary and solid. In the present study, a case of isolated small intestine metastasis of ovarian papillary cystadenocarcinoma was reported. A 7-year-old female mixed-breed dog presented with a mass in the left upper quadrant with progressive enlargement of the abdomen, periodic bloody discharge from the vulva and incontinence. The tumor was histologically characterized by the presence of cysts and proliferation of papillae, both lined by single- or multi-layered pleomorphic epithelial cells. Furthermore, the mass was composed by intense cellular and nuclear pleomorphism and numerous mitotic figures. These findings indicate a tumor of high-grade malignancy with infiterative tumor cells resembling the papillary ovarian tumor in the serosal surface of the small intestine along with an intact serosa. Immunohistochemically, tumor was positive for CK7 and negative immunoreactivity for CK20. The histopathologic features coupled with the CK7 immunoreactivity led to a diagnosis of high grade ovarian papillary cystadenocarcinoma. To the best of our knowledge, this is the first case of small intestine serousal surface metastasis from ovarian papillary cystadenocarcinoma.

Detection of Helicobacter spp. DNA in the colonic biopsies of stray dogs: molecular and histopathological investigations

Abstract

Virtual Slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1957989294118782.

Giant intraosseous schwannoma of scapula: a rare case report and review of the literature

Bony schwannoma is a rare benign tumor derived from schwann cells of nerve fibers in the bone. It accounts for less than 1% of bony benign tumor, and prone to occur in the sacrum and mandible, occurrence in scapula is very rare. Here we report a 42-year-old woman with the chief complaint of pain in the left scapula. Imaging examination showed a giant, irregular, swelling lesion with distinct border involving the left scapula, extending into the left shoulder glenoid and pressing the surrounding soft tissues. Needle biopsy showed that the tumor was composed of spindle cells with S-100 protein positive, mimicking a benign neurogenic tumor. Then a complete excision was performed by removing the tumor and the surrounding tissues including partial left shoulder glenoid. Histologically, Antoni type A areas were the predominant microscopic pattern with occasional alternation by Antoni type B areas. Immunohistochemistry found that the neoplastic cells were scatteredly positive for S-100 protein. All these features suggest a diagnosis of an intraosseous schwannoma of the left scapula. Follow-up of the patient for ten months found no recurrence or sign of other tumors following complete tumor resection without any adjuvant therapy. In conclusion, this case of giant intraosseous schwannoma of the scapula is a rare benign bony tumor, and its diagnosis combined with clinical, imaging and pre-operative needle biopsy is important to guide further therapy, and avoid overtreatment.

Cutaneous mast cell tumor (Mastocytoma): cyto- histopathological and haematological investigations

Cutaneous mast cell tumours (MCTs) are the most common skin tumours in dogs. Due to the prevalence of canine MCTs and the variable biologic behavior of this disease, accurate prognostication and a thorough understanding of MCT biology are critical for the treatment of this disease. A cytologic diagnosis of mast cell tumor with evidence of prior hemorrhage was made, and the masses were surgically removed. Cytological evaluation of fine-needle aspirates from the cutaneous mass from the axillary comprised many well-differentiated, highly granulated mast cells with moderate numbers of eosinophils. Nuclei were varied in size and shape with high nuclear’to’cytoplasmic ratio, prominent nucleoli, marked atypical and mitotic figures. Microscopically, mass consisted of sheets of neoplastic round cells that formed nonencapsulated nodules in the dermis and infiltrated into the adjacent dermal collagen, and also there was diffuse subcutis invasion of round to pleomorphic tumor cells. Tumor cells had moderate to abundant cytoplasm, round to ovoid nuclei with scattered chromatin, and mitotic figures. In this tumor, cytoplasmic granules showed atypical metachromasia. In addition, eosinophils were scattered among the mast cells at the periphery of the nodules. The presence of eosinophils and the observation, at high magnification, of cells with cytoplasmic metachromatic granules. Invasion of the deep subcutaneous fat or cutaneous muscles were a common feature of grade III tumour. Finally, a diagnosis of grade III cutaneous mast cell tumor was made.