Cerebellar leptomeningeal carcinomatosis in a dog

Malignant transformation and subsequent leptomeningeal carcinomatosis of a gastric polyp in a dog

Progressive carcinogenesis of a gastric polyp with transformation to gastric adenocarcinoma and subsequent development of leptomeningeal carcinomatosis is described in an adult male Scottish terrier. Presenting clinical signs consisted of vomiting with intermittent hematemesis. Surgical biopsies over the course of 14 months documented the progression from gastric polyp to minimally invasive gastric carcinoma to invasive gastric adenocarcinoma, a pathogenesis not previously documented in veterinary oncology. The patient ultimately developed neurologic pathology and was euthanized, and necropsy evaluation identified widespread carcinomatosis with accompanying leptomeningeal metastasis. As in humans, gastric polyps in dogs rarely have malignant potential.

Detection of Leptomeningeal Carcinomatosis by Cerebrospinal Fluid in a Dog with a Negative MRI

An 11 yr old female French bulldog was presented for acute onset of seizures and a 2 wk history of disorientation. On physical examination, a nodular mass at the fourth mammary gland level was observed. Neurological evaluation showed obtundation and compulsive behavior. Brain MRI study did not reveal any abnormalities. Cerebrospinal fluid (CSF) collected from the cerebellomedullary cistern showed a marked increase of total nucleated cell count (400 cells/μL). Cytological evaluation identified the presence of a monomorphic round cell population characterized by large cell bodies, a single eccentrical located nucleus with high nuclear:cytoplasmatic ratio, and marked atypia with anisocytosis, anisokaryosis, and multiple nucleoli. Leptomeningeal carcinomatosis (LC) was suspected. The dog was euthanatized for worsening of clinical signs. Post-mortem examination identified an anaplastic mammary carcinoma in the nodular mammary mass. Infiltration by neoplastic cells exhibiting the same morphological features was detected along leptomeninges of the telencephalon and cerebellum associated with cortical and subcortical parenchymal micrometastases. To our knowledge, this is the first case of LC in a dog detected by CSF evaluation but without any MRI abnormalities. This finding emphasizes the usefulness of CSF cytology in patients with suspected LC even in the absence of any MRI identifiable lesions.

Neuropathology of Central and Peripheral Nervous System Lymphoma in Dogs and Cats: A Study of 92 Cases and Review of the Literature

The literature about nervous system lymphoma (NSL) in dogs and cats is fragmentary, based on a few case series and case reports with heterogeneous results. The aim of our study was to retrospectively analyze 45 cases of canine and 47 cases of feline NSL and compare our results with previously reported data, also providing an extensive literature review. Breed, age, gender, clinical signs, type, and neurolocalization were recorded for each case. The pathological patterns and phenotype were assessed by histopathology and immunohistochemistry. The occurrence of central and peripheral NSL was similar between the two species in both primary and secondary types. NSL occurred with a slightly higher prevalence in Labrador Retrievers, and spinal cord lymphoma (SCL) was associated with young age in cats. The most frequent locations were the forebrain in dogs and the thoracolumbar segment in cats. Primary central nervous system lymphoma (CNSL) in cats most frequently involved the forebrain meninges, particularly as a B-cell phenotype. Peripheral NSL mostly affected the sciatic nerve in dogs and had no preferred location in cats. Nine different pathological patterns were identified, with extradural as the most prevalent SCL pattern in both species. Finally, lymphomatosis cerebri was described for the first time in a dog.

Lymphatic Drainage Mapping with Indirect Lymphography for Canine Mammary Tumors

Simple Summary

Mammary gland tumours are the most common canine neoplasms. They account for 25–50% of all tumors diagnosed in bitches. Metastases and recurrences develop in about 35–70% of bitches following excision. The presence of regional lymph node metastases is a relevant factor affecting prognosis and treatment in cases of mammary gland tumors. The sentinel lymph node (SLN) is the first lymph node (or nodes) in the regional lymphatic basin that receives lymphatic flow from the primary neoplasm. As mammary gland tumors mainly spread by lymphatic vessels invasion, conceptually, distant metastasis should not be present if the SLN does not have evidence of a tumor burden. In the present study, an indirect lymphography was used for sentinel lymph node mapping in a cohort of 14 adult female dogs with 24 mammary tumors involving the third to the fifth mammary gland. Contrast was injected around the mammary tumor, and lymph nodes that picked up the contrast were visible after 24 h. The results of this study indicate that the lymph drainage pattern of the neoplastic mammary gland may be different for each tumor. The knowledge of the SLN of the neoplastic mammary glands should be of high importance for the surgeon not only for performing the most adequate surgical excision but also for determining an accurate post-surgical prognosis.

Abstract

Mammary gland tumors are the most common canine neoplasms. They account for 25–50% of all tumors diagnosed in bitches. Metastases and recurrences develop in about 35–70% of bitches following excision. The presence of regional lymph node metastases is a relevant factor affecting prognosis and treatment in cases of mammary gland tumors. The sentinel lymph node (SLN) is the first lymph node (or nodes) in the regional lymphatic basin that receives lymphatic flow from the primary neoplasm. The aim of this study is to investigate the SLN with indirect lymphography for a mammary tumor in dogs. The knowledge of the precise drainage pattern and SLN of the neoplastic mammary glands would provide clinically relevant information to the surgeon and to the oncologist, and it would be of high importance for the surgeon not only for performing the most adequate surgical excision but also for determining an accurate post-surgical prognosis.

Clinical, CT, and ultrasonographic features of canine and feline pleural and peritoneal carcinomatosis and sarcomatosis

Carcinomatosis and sarcomatosis describe the widespread dissemination of metastatic neoplastic cells throughout the body. Studies describing their clinical and imaging features in veterinary patients are limited. The objective of this retrospective, multicenter, cross-sectional study is to describe the clinical, ultrasonographic, and CT features of pleural and peritoneal carcinomatosis and sarcomatosis in dogs and cats to aid detection and differentiation of these lesions. Medical records and CT and ultrasonographic images were reviewed. Although a large degree of overlap was observed between the imaging features and clinical signs of canine and feline carcinomatosis and sarcomatosis, some distinguishing features were observed. Dogs were significantly more likely to present with abdominal pain compared to cats (P = .022), whereas cats more commonly presented with inappetence (P = .019). Dogs with sarcomatosis had a significantly heavier bodyweight than dogs with carcinomatosis (P = .005), largely due to a higher prevalence of splenic hemangiosarcoma in this patient cohort. Peritoneal effusion was more frequently observed in dogs with carcinomatosis compared to dogs with sarcomatosis (P = .021). Imaging and clinical features observed in this study may help to distinguish sarcomatosis and carcinomatosis lesions. Due to the large degree of overlap observed, cytological or histopathological analysis is recommended for definitive diagnosis.

Diagnosis of meningeal melanomatosis in a dog using magnetic resonance imaging and cerebrospinal fluid findings

A 13-year-old spayed female Labrador Retriever was presented with severe progressive tetraparesis. The neuroanatomic localization was the C1-C5 spinal cord segments with brainstem or cranial nerve involvement. Magnetic resonance imaging revealed diffuse T1-weighted and T2-weighted hyperintense lesions with strong contrast enhancement spreading through meninges of the cervical spinal cord and the brain. Few small round areas showing T1-weighted hyperintensity and T2-weighted hypointensity were scattered within the lesions. Cerebrospinal fluid analysis revealed neoplastic round cells and possible melanocytes. Malignant melanoma was suspected. At necropsy, the brain and the entire spinal cord were covered with thick, dark membranous tissue. Based on histopathologic findings, a positive response against Melan-A, and no melanoma identified outside the central nervous system, primary meningeal melanomatosis was diagnosed.

Retrospective characterization of coma and stupor in dogs and cats presenting to a multicenter out-of-hours service (2012-2015): 386 animals

OBJECTIVE

To describe the signalment, etiology, and short-term outcome of dogs and cats presenting in a coma or stupor.

DESIGN

Retrospective study conducted between May 2012 and February 2015.

SETTING

Multicenter out-of-hours emergency service provider.

ANIMALS

Three hundred eighty-six patients presenting in a coma or stupor to a multicenter out-of-hours emergency care provider.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Records were reviewed to determine the most likely etiology of coma or stupor. Short-term outcomes were defined as deceased (died or euthanized) or transferred (case handed over to a daytime clinic or discharged). There were 168 dogs (coma n = 112, stupor n = 56) and 218 cats (coma n = 148, stupor n = 70) identified. Coma and stupor were more prevalent in cats compared to dogs, and Chihuahuas were over represented. Blood glucose concentrations were frequently outside established reference intervals. Excluding undetermined causes, the most common causes in dogs included traumatic brain injury (TBI) 16.0% (n = 27, deceased n = 22), hypoglycemia 10.7% (n = 18, deceased n = 8), shock 10.1% (n = 17, deceased n = 16), seizure 9.5% (n = 16, deceased n = 13), and renal or hepatic dysfunction 5.3% (n = 9, deceased n = 7). For cats, the most common causes included TBI 21.6% (n = 47, deceased n = 38), renal or hepatic dysfunction 13.3% (n = 29, deceased n = 25), intoxication 10.1% (n = 22, deceased n = 18), hypoglycemia 6.0% (n = 13, deceased n = 4), and shock 5.0% (n = 11, deceased n = 8). When treatment was attempted, 46.0% of dogs (n = 44/96) and 41.2% of cats (n = 35/85) survived to be transferred. Compared to all other etiologies, death was less likely when coma or stupor was attributed to hypoglycemia.

CONCLUSION

In cases where a cause was determined, TBI was the predominant etiology of coma and stupor for both species. With the exception of coma and stupor attributed to hypoglycemia, the overall short-term prognosis was poor.

Meningeal carcinomatosis and spinal cord infiltration caused by a locally invasive pulmonary adenocarcinoma in a cat

Case summary

A 12-year-old domestic shorthair cat was presented with acute non-painful hindlimb proprioceptive ataxia localising to T3–L3 spinal cord segments. MRI revealed paravertebral muscular hyperintensity on T2-weighted images at the level of T7–T8 vertebrae. The cat improved on conservative management but deteriorated 3 months later. Repeated MRI showed meningeal enhancement at the same level and hyperintensity of the paravertebral musculature extending to the right thoracic wall and pleural space on short tau inversion recovery images. Thoracic CT showed mineralised lesions of the right lung, restricted pleural effusion and expansile bone lesions affecting multiple ribs. The cat had been treated for pyothorax 5 years earlier but manifested no current respiratory signs. Cerebrospinal fluid (CSF) examination showed lymphocytic pleocytosis but no neoplastic cells. Biopsy of the affected muscles and cytology of the lung and pleural lesions suggested a malignant epithelial cell tumour. Post-mortem examination confirmed a pulmonary adenocarcinoma locally infiltrating the thoracic wall, T7–T8 vertebrae and the spinal cord white matter. Meningeal carcinomatosis was detected with neoplastic cells invading the ventral median fissure of the spinal cord. No metastases were observed in other organs, indicating that neoplastic cells reached the spinal cord by direct extension.

Relevance and novel information

Spinal meningeal carcinomatosis has not been reported in dogs or cats with extraneural tumours but is a well-recognised condition in humans. A metastatic cause of meningeal enhancement should be considered in patients with neurological signs of unknown origin. Imaging findings and CSF results can be non-specific.

Meningeal carcinomatosis and spinal cord infiltration caused by a locally invasive pulmonary adenocarcinoma in a cat

Case summary

A 12-year-old domestic shorthair cat was presented with acute non-painful hindlimb proprioceptive ataxia localising to T3-L3 spinal cord segments. MRI revealed paravertebral muscular hyperintensity on T2-weighted images at the level of T7-T8 vertebrae. The cat improved on conservative management but deteriorated 3 months later. Repeated MRI showed meningeal enhancement at the same level and hyperintensity of the paravertebral musculature extending to the right thoracic wall and pleural space on short tau inversion recovery images. Thoracic CT showed mineralised lesions of the right lung, restricted pleural effusion and expansile bone lesions affecting multiple ribs. The cat had been treated for pyothorax 5 years earlier but manifested no current respiratory signs. Cerebrospinal fluid (CSF) examination showed lymphocytic pleocytosis but no neoplastic cells. Biopsy of the affected muscles and cytology of the lung and pleural lesions suggested a malignant epithelial cell tumour. Post-mortem examination confirmed a pulmonary adenocarcinoma locally infiltrating the thoracic wall, T7-T8 vertebrae and the spinal cord white matter. Meningeal carcinomatosis was detected with neoplastic cells invading the ventral median fissure of the spinal cord. No metastases were observed in other organs, indicating that neoplastic cells reached the spinal cord by direct extension.

Relevance and novel information

Spinal meningeal carcinomatosis has not been reported in dogs or cats with extraneural tumours but is a well-recognised condition in humans. A metastatic cause of meningeal enhancement should be considered in patients with neurological signs of unknown origin. Imaging findings and CSF results can be non-specific.

MR imaging of histiocytic sarcoma of the canine brain

Histiocytic sarcomas are characterized by proliferation and/or infiltration of neoplastic histiocytes localized to specific organs, unlike malignant histiocytosis which involves many organ systems. Only a few cranial histiocytic sarcomas have been reported. Here we describe four dogs that presented with neurological deficits referable to the forebrain, and were diagnosed histologically as having histiocytic sarcoma. Using magnetic resonance (MR) imaging, the tumors were characterized by a T2-hyperintense and T1-isointense mass in one dog, T2- and T1-isointense extraaxial masses in two dogs, and a diffuse T2-hyperintense lesion over the left cerebral cortex in one dog. All tumors had contrast enhancement. MRI features in three of the four dogs were similar to that of meningioma, supported by the observation of a dural tail in two of these three dogs, and a broad base of attachment in the other. In the other dog the imaging findings were similar to those of encephalitis. Intracranial histiocytic sarcoma does not appear to have specific MR imaging features and can be confused with meningioma or encephalitis.