Mass-to-splenic volume ratio and splenic weight as a percentage of body weight in dogs with malignant and benign splenic masses: 65 cases (2007-2008)

MicroRNAs in serum and tissue can differentiate splenic hemangiosarcoma from other splenic masses in dogs

Splenic masses are common in dogs and vary dramatically in their clinical behavior. Clinically, and even with histology, it can be challenging to differentiate between benign and malignant splenic masses. Hemangiosarcoma (HSA), the most common malignancy of the spleen, is a very aggressive tumor with a poor prognosis. We hypothesize that microRNAs (miRNAs) in mass tissue and serum can differentiate between HSA and other splenic masses. Fifty-nine miRNAs were investigated by reverse-transcription followed by real-time quantitative polymerase chain reaction (RT-qPCR) in serum and/or tissue from dogs with HSAs (serum n = 24 and tissue n = 17; postsplenectomy serum n = 11), lymphomas (serum n = 8 and tissue n = 11), nonangiomatous nonlymphomatous sarcomas (serum n = 6 and tissue n = 10), histiocytic sarcomas (tissue n = 4), benign splenic masses (myelolipomas, nodular hyperplasia, and hematomas; total serum n = 21 and total tissue n = 35), and normal dogs (serum n = 14 and tissue n = 7). Numerous miRNAs were differentially expressed in serum and tissue of HSA cases compared to those with other splenic masses or normal spleens. In serum, our 5-miRNA model (miR-135a-5p, miR-10a, miR-450b, miR-152-3p, and miR-126-5p) accurately classified 100% (24/24) of dogs with HSA from normal dogs and those with a benign splenic mass (recall = 1 for HSA). The overall accuracy of the model was 86%. In HSA and benign splenic mass tissues, our 3-miRNA model (miR-126-5p, miR-502-3p, and miR-452-5p) accurately classified 96% of the cases. This study demonstrates the utility of miRNA models in serum and tissue for screening and diagnosis of HSA in dogs. Future studies include the evaluation of prospective and prediagnosis serum samples.

Incidence of splenic malignancy and hemangiosarcoma in dogs undergoing splenectomy surgery at a surgical specialty clinic: 182 cases (2017-2021)

The objectives of this study were to evaluate the risk and predictive factors of splenic malignancy and hemangiosarcoma in dogs undergoing splenectomy at a surgical specialty clinic. Medical records, hematologic results, surgical reports, and histopathologic results from 182 dogs that underwent splenectomy for the treatment of splenic masses or nodules were reviewed retrospectively. The majority of dogs (57.7%) had benign splenic diagnoses with no malignancy. Hemangiosarcoma was diagnosed in 32.4% of the dogs. A final multivariable model indicated that thrombocytopenia, anemia, and a smaller diameter of the largest splenic nodule were risk factors for hemangiosarcoma (P<0.001), and hemoperitoneum (P = 0.01) was an additional risk factor when nodule diameter was not evaluated. There were 91 dogs that had hemoperitoneum, and 60.4% of those dogs had malignant splenic lesions. Of the 33 dogs that underwent a splenectomy for incidentally identified splenic lesions, 93.9% had benign splenic lesions. Breed size was not a significant predictor of splenic malignancy risk; however, all 6 of the German shepherds included in the study had a hemangiosarcoma diagnosis. Overall prevalence of splenic malignancy including HSA may be overestimated in some canine populations.

Gadoxetate disodium (Gd-EOB-DTPA) contrast-enhanced magnetic resonance imaging for differentiation between benign and malignant splenic lesions in dogs

Malignant splenic lesions in dogs are common, with hemangiosarcoma diagnosed most frequently, and there have been no consistent clinicopathologic, gross, or imaging characteristics identified that differentiate malignant from benign splenic lesions. Histopathology is required for definitive diagnosis, and given the poor long-term prognosis of malignant splenic lesions, a noninvasive tool to aid in diagnosis would be valuable. This prospective cohort study utilized gadoxetate disodium, a liver-specific contrast agent (Gd-EOB-DPTA; Eovist), to identify the general lesion and pre- and postcontrast signal characteristics of benign and malignant splenic and hepatic lesions in dogs with naturally occurring disease. Twenty-five dogs were enrolled, Eovist-enhanced MRI was performed, and dogs were taken to surgery for splenectomy and other organ biopsy. All histopathology and MRI studies were evaluated by a single pathologist and a single radiologist, respectively. The associations between the tumor type and numerous variables defined on MRI were evaluated using Fisher's exact tests, and the significance was identified at a P-value of .05. Malignant splenic masses were identified in 11/25 (44%) dogs, and 5/11 malignancies represented hemangiosarcoma. The presence of abdominal effusion (P = .017) and the presence of hepatic nodules on MRI (P = .009) were associated with splenic malignancy. There were no benign T2 hyperintense and no malignant T2 hypointense lesions (P = .021). Utilization of the T2 W MRI sequence may aid in the identification of malignant splenic lesions, particularly when accompanied by abdominal effusion and hepatic lesions.

Prognostic value of tumour-related factors associated with canine retroperitoneal hemangiosarcoma in comparison with other anatomic presentations: A retrospective observational study

BACKGROUND

Dogs with retroperitoneal hemangiosarcoma (HSA) exhibit variable postoperative median survival times (MST).

OBJECTIVE

To retrospectively evaluate the prognostic value of selected tumour-related factors, such as tumour size, rupture, invasion into adjacent tissue, involvement of lymph node and distant metastasis, they were analysed in dogs with retroperitoneal HSA.

METHODS

Ten dogs with retroperitoneal HSA managed solely with surgical excision were reviewed and compared with spleen (71) and liver (9) HSA. The Kaplan-Meier method and log-rank analysis were used compare MSTs between factors. Multivariable Cox proportional-hazard analysis was used to compare differences between arising sites.

RESULTS

Retroperitoneal HSA showed comparatively longer postoperative MST compared with that of spleen and liver HSA and demonstrated significantly longer MST (p = 0.003) for tumours ≥5 cm (195 days) than <5 cm (70 days). Spleen HSA revealed significantly shorter MSTs in involvement of distant lymph nodes (23 days) and distant metastasis (39 days) than those in negative (83 days, p = 0.002 and 110 days, p < 0.001, respectively). Liver HSA also revealed significantly shorter MST (16.5 days compared with 98 days, p = 0.003) for distant metastasis. Additionally, hazard ratios (HRs) and their forest plot for overall HSA revealed as poor prognostic factors, arising sites (spleen; HR 2.78, p = 0.016 and liver; HR 3.62, p = 0.019), involvement of distant lymph nodes (HR 2.43, p = 0.014), and distant metastasis (HR 2.86, p < 0.001), and as better prognostic factor of tumour size ≥5 cm (HR 0.53, p = 0.037).

CONCLUSION

In combination with overall HSA, retroperitoneal HSA shows comparatively longer postoperative MST compared to spleen and liver HSA, associated with tumour size ≥5 cm suggesting better prognostic factor.

Pathological Characterization and Risk Factors of Splenic Nodular Lesions in Dogs (Canis lupus familiaris)

In dogs, the spleen is a secondary lymphoid organ that can be affected by both neoplastic and non-neoplastic nodules. In general, few studies relate histopathological diagnosis to tumor size and the number of nodules in spleen biopsies. Some of these studies are inconclusive regarding the difference between neoplastic and non-neoplastic lesions and have small sample sizes or do not consider all splenic lesions. This study aimed to characterize splenic masses and determine risk factors for spleen tumors in dogs. A total of 507 histological reports corresponding to the diagnosis of splenic lesions in dogs from a private laboratory of animal pathology in the Metropolitan Region, Chile, were used. Data were analyzed by descriptive statistics and multiple logistic regression. The most frequent neoplastic and non-neoplastic diagnoses were hemangiosarcoma and hyperplasia, respectively. Most of the cases occurred in male (265 cases, 52.3%), senior (421 cases, 83%), and purebred individuals (342 cases, 67.5%). The most affected breeds were the Cocker Spaniel, German Shepherd, and Labrador Retriever. The most frequent lesion was a single nodule. The variables that exhibited a greater risk for the presentation of splenic neoplasia were male sex (odds ratio (OR) = 16.21; 95% confidence interval (CI) 1.741-150.879; p = 0.014), the presence of two or more splenic nodules (OR = 3.94; 95% CI 2.168-7.177; p < 0.001), an increase in nodule size greater than 2 cm (OR for quartiles 2, 3 and 4 of 2.2; 95% CI 1.036-4.941; p = 0.041, 2.9; 95% CI 1.331-6.576; p = 0.008, and 3.6; 95% CI 1.562-8.499; p = 0.003, respectively), and increasing age (OR = 1.23; 95% CI 1.048-1.436; p = 0.011). On the other hand, males exhibited a lower risk as age increases (OR = 0.76; 95% CI 0.615-0.928; p = 0.008). In conclusion, this study identified that males, multinodular presentation, nodule size, and age are risk factors for the occurrence of splenic neoplasia in dogs, knowledge that will contribute to the diagnostic management of dogs with spleen lesions.

Retrospective evaluation of the diagnostic utility of computed tomography in dogs with nontraumatic hemoperitoneum: 26 cases (2015-2020)

OBJECTIVE

To describe the appearance of lesions noted on abdominal computed tomography (CT) in dogs with spontaneous hemoperitoneum and determine the utility in using CT to differentiate benign from malignant lesions.

DESIGN

Retrospective case series.

SETTING

Single-center, university veterinary teaching emergency service.

ANIMALS

Twenty-six dogs presented between 2015 and 2020 with spontaneous hemoperitoneum confirmed via abdominocentesis with pre- and postcontrast abdominal CT performed prior to surgery or euthanasia.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

On histopathological diagnosis, 20 of 26 lesions were found to be malignant, and 6 of 26 were benign. Two radiologists reviewed the CTs. Radiologist 1 correctly identified 5 of 6 (83.3%) benign cases and 18 of 20 (90%) malignant cases. Radiologist 2 correctly identified 2 of 6 (33.3%) benign lesions and 18 of 20 (90%) malignant cases. Of the 10 imaging descriptors evaluated, none were significantly associated with the histological diagnosis.

CONCLUSIONS

Results from the current study suggest that abdominal CT imaging of spontaneous hemoperitoneum cases is not a reliable indicator of malignancy versus benignancy. As such, prognosis should not be defined using this modality alone prior to emergency surgery and instead should be concluded based on the clinical course of the patient and histopathological findings of the resected tissues after surgery.

Diagnosis, Prognosis, and Treatment of Canine Hemangiosarcoma: A Review Based on a Consensus Organized by the Brazilian Association of Veterinary Oncology, ABROVET

Hemangiosarcoma is a mesenchymal neoplasm originating in the endothelial cells of blood vessels; they can be classified as non-visceral and visceral types. Non-visceral hemangiosarcomas can affect the skin, subcutaneous tissues, and muscle tissues; visceral hemangiosarcomas can affect the spleen, liver, heart, lungs, kidneys, oral cavity, bones, bladder, uterus, tongue, and retroperitoneum. Among domestic species, dogs are most affected by cutaneous HSA. Cutaneous HSA represents approximately 14% of all HSA diagnosed in this species and less than 5% of dermal tumors, according to North American studies. However, Brazilian epidemiological data demonstrate a higher prevalence, which may represent 27 to 80% of all canine HSAs and 13.9% of all skin neoplasms diagnosed in this species. Cutaneous HSA most commonly affects middle-aged to elderly dogs (between 8 and 15 years old), with no gender predisposition for either the actinic or non-actinic forms. The higher prevalence of cutaneous HSA in some canine breeds is related to lower protection from solar radiation, as low skin pigmentation and hair coverage lead to greater sun exposure. Actinic changes, such as solar dermatosis, are frequent in these patients, confirming the influence of solar radiation on the development of this neoplasm. There are multiple clinical manifestations of hemangiosarcoma in canines. The diagnostic approach and staging classification of cutaneous HSAs are similar between the different subtypes. The definitive diagnosis is obtained through histopathological analysis of incisional or excisional biopsies. Cytology can be used as a presurgical screening test; however, it has little diagnostic utility in cases of HSA because there is a high risk of blood contamination and sample hemodilution. Surgery is generally the treatment of choice for dogs with localized non-visceral HSA without evidence of metastatic disease. Recently, electrochemotherapy (ECT) has emerged as an alternative therapy for the local ablative treatment of different neoplastic types; the use of radiotherapy for the treatment of dogs with cutaneous HSA is uncommon. There is greater consensus in the literature regarding the indications for adjuvant chemotherapy in subcutaneous and muscular HSA; doxorubicin is the most frequently used antineoplastic agent for subcutaneous and muscular subtypes and can be administered alone or in combination with other drugs. Other therapies include antiangiogenic therapy, photodynamic therapy, the association of chemotherapy with the metronomic dose, targeted therapies, and natural products. The benefits of these therapies are presented and discussed. In general, the prognosis of splenic and cardiac HSA is unfavorable. As a challenging neoplasm, studies of new protocols and treatment modalities are necessary to control this aggressive disease.

Evaluation of the validity of the double two-thirds rule for diagnosing hemangiosarcoma in dogs with nontraumatic hemoperitoneum due to a ruptured splenic mass: a systematic review

OBJECTIVE

To evaluate the validity of the double two-thirds rule for a diagnosis of splenic hemangiosarcoma in dogs with nontraumatic hemoperitoneum due to a ruptured splenic mass.

SAMPLE

Systematic literature review.

PROCEDURES

3 databases (PubMed, CAB abstracts, and World of Science) were searched in November 2020. Articles were included if data on dogs with nontraumatic hemoperitoneum due to a splenic mass were included and subsequent pathologic diagnosis could be determined.

RESULTS

In total, 2,390 unique articles were identified, with 66 articles meeting the criteria for full-text review and 14 articles included for analysis. A total of 1,150 dogs were evaluated, with 73.0% (840/1,150) of dogs being diagnosed with a malignant splenic lesion and 27.0% (310/1,150) being diagnosed with a benign splenic lesion. Of the malignancies, 87.3% (733/840) were hemangiosarcoma. Levels of evidence were low, and bias was high as most included studies were retrospective case series.

CLINICAL RELEVANCE

The double two-thirds rule should be refined when evaluating dogs with nontraumatic hemoperitoneum from a ruptured splenic mass, with more dogs being diagnosed with a malignancy and hemangiosarcoma specifically than the double two-thirds rule indicates. These findings may be useful in an emergency setting to guide owners on potential diagnoses for dogs with nontraumatic hemoperitoneum due to a ruptured splenic mass. However, there remains a portion of these dogs with benign conditions and nonhemangiosarcoma malignancies that may have a good long-term prognosis compared to dogs with hemangiosarcoma. Studies with higher levels of evidence, lower risks of bias, and large case numbers are needed in the literature.

Epidemiology and Survival of Dogs Diagnosed with Splenic Lymphoid Hyperplasia, Complex Hyperplasia, Stromal Sarcoma and Histiocytic Sarcoma

Canine splenic fibrohistiocytic nodules traditionally encompassed benign lymphoid hyperplasia, complex hyperplasia, and malignant fibrous histiocytoma. The latter has been recently re-classified into histiocytic sarcoma and stromal sarcoma. Reliable indicators of post-splenectomy survival and demographic factors predisposing to the four types of nodules are not completely understood. This study aims to estimate frequency, survival times, and identify risk factors of splenectomized dogs diagnosed with lymphoid hyperplasia, complex hyperplasia, histiocytic sarcoma, and stromal sarcoma using medical records containing histopathological diagnosis from the VetCompass Australia database (1989−2018), which collects demographic, and clinical information from veterinary clinics. Out of 693 dogs, 315 were diagnosed with fibrohistiocytic nodules, mostly lymphoid hyperplasia (169/693, 24.4%), followed by stromal sarcoma (59/693, 8.5%), complex hyperplasia (55/693, 7.9%), and histiocytic sarcoma (32/693, 4.6%). Dogs aged 8−10 years were more likely to be diagnosed with histiocytic or stromal sarcoma than lymphoid hyperplasia. Dogs diagnosed with lymphoid hyperplasia had a longer survival time than those with other diagnoses (median > 2 years). Dogs diagnosed with histiocytic sarcoma had longer survival times (median 349 days) than stromal sarcoma (median 166 days). Results suggest that knowledge of the type of splenic fibrohistiocytic nodule, patients’ age, and sex can be used to increase prognostic accuracy.

Diagnostic value of the ultrasonographic description of a splenic mass or nodule as cavitated in 106 dogs with nontraumatic hemoabdomen

OBJECTIVE

To assess the diagnostic value of the ultrasonographic description of a splenic mass or nodule as cavitated in dogs with nontraumatic hemoabdomen.

ANIMALS

106 dogs with a nontraumatic hemoabdomen that underwent abdominal ultrasonography and splenectomy with histologic examination of splenic lesions between 2005 and 2018.

PROCEDURES

Medical records were reviewed for abdominal ultrasonographic and histologic findings. Diagnostic performance of ultrasonographic description of a splenic mass or nodule as cavitated as evidence of hemangiosarcoma or any malignancy was evaluated.

RESULTS

Ultrasonographic description of splenic lesions as cavitated had poor diagnostic utility in predicting presence of hemangiosarcoma or malignancy. Sensitivity and specificity of this test were 41.9% (95% CI, 30.5% to 54.3%) and 51.2% (95% CI, 36.8% to 65.4%), respectively, for detecting hemangiosarcoma, with positive and negative predictive values of 55.3% (95% CI, 41.2% to 68.6%) and 37.9% (95% CI, 26.6% to 50.8%), respectively. Results were similar for detecting malignancy. Cavitated lesions outside of the spleen were too rare for statistical analysis to be of value.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that relying on ultrasonographic description of cavitation to diagnose splenic lesions as malignant in dogs with nontraumatic hemoabdomen is unfounded. Other preoperative diagnostic tests may be more valuable in determining short- and long-term prognoses.

Development of perioperative premature ventricular contractions as an indicator of splenic hemangiosarcoma and median survival times

OBJECTIVE

The objectives of this study are (1) to determine whether there is an association between dogs with splenic hemangiosarcoma (HSA) and the development of premature ventricular contractions (VPCs), (2) to determine if there is a higher likelihood for dogs with ruptured splenic masses to be diagnosed with HSA and to develop VPCs, (3) to determine if the development of VPCs affects median survival times compared to dogs with benign or non-HSA malignant splenic masses.

STUDY DESIGN

Retrospective case series.

ANIMALS

Forty-five dogs.

METHODS

Medical records of dogs undergoing splenectomy were reviewed for signalment, perioperative electrocardiogram (ECG), hematological values, histologic diagnosis, metastasis, and survival times. ECGs were performed preoperatively, intraoperatively, and continuously postoperatively. The presence of VPCs was recorded. The data were evaluated for an association between the development of VPCs and the histologic diagnosis of HSA.

RESULTS

Eighteen out of 45 (40%) dogs were diagnosed with HSA with 13/18 (72%) dogs having VPCs postoperatively (P = .02). Ruptured splenic HSA and VPCs were noted in 13 dogs (P = .73). An association between dogs with and without VPCs diagnosed with HSA and median survival times could not be established.

CONCLUSION

Postoperative VPCs were more likely with splenic HSA. Splenic masses were more likely to be HSA if ruptured but less likely to develop VPCs. Development of VPCs does not affect median survival times.

CLINICAL SIGNIFICANCE

Development of postoperative VPCs may be a potential indicator of HSA, however, this warrants further investigations. Development of VPCs does not have a deleterious effect on survival.

Identification of serum microRNAs with differential expression between dogs with splenic masses and healthy dogs with histologically normal spleens

OBJECTIVE

To identify differential microRNA (miRNA) expression in dogs with splenic hemangiosarcoma, splenic hematoma, and histologically normal spleens.

ANIMALS

Dogs with splenic hemangiosarcoma (n = 10), splenic hematoma (n = 5), and histologically normal spleens (n = 5).

PROCEDURES

Splenic tissue and serum samples were collected from dogs with splenic masses (ie, hemangiosarcoma or hematoma samples) and healthy control dogs (ie, control samples), and total RNA was extracted. Reverse transcription quantitative real-time PCR was performed with 28 miRNAs associated with hemangiosarcoma, angiosarcoma, or associated genes. Differential expression analysis was performed.

RESULTS

Control tissue and serum samples had similar miRNA expression patterns, and hemangiosarcoma tissue and serum samples did not. Hemangiosarcoma serum samples had higher expression than hemangiosarcoma tissue for 13 miRNAs and lower expression for 1 miRNA. Control tissue and hemangiosarcoma tissue had varying expressions for 12 miRNAs, with 10 more highly expressed in control samples and 2 more highly expressed in hemangiosarcoma samples. Five miRNAs (miR-214-3p, miR-452, miR-494-3p, miR-497-5p, miR-543) had significantly different expression in serum between dogs with splenic masses (ie, hemangiosarcoma or hematoma) and serum of dogs with histologically normal spleens, with higher expression in the serum of dogs with splenic masses for all 5 miRNAs.

CONCLUSIONS AND CLINICAL RELEVANCE

5 circulating miRNAs were identified that distinguished dogs with splenic hemangiosarcoma or hematoma from those with histologically normal spleens. These 5 miRNAs had higher expression in dogs with splenic masses, indicating upregulation of these circulating miRNAs occurs in these splenic disease states. These miRNAs may be useful as a noninvasive screening tool that uses serum to identify dogs with splenic masses.

Canine and feline haemangiosarcoma

INTRODUCTION

Haemangiosarcoma (HSA) is a malignant neoplasm of dogs and cats that is suspected to originate from a pluripotent bone marrow progenitor with a complex and multifactorial pathogenesis.

APPROACH

Pertinent literature was identified, reviewed, and summarized for inclusion in the manuscript.

RESULTS/INTERPRETATION

Dogs are more frequently diagnosed with HSA than cats, and primary sites of this disease include dermal, subcutaneous/intramuscular, and visceral (most commonly the spleen). Dogs and cats with HSA generally have a poor prognosis owing to the rapid and widespread metastasis typically associated with this disease. However, some forms such as cutaneous HSA behave in a less aggressive fashion with improved outcomes. Surgical excision and anthracycline-based chemotherapy remain the mainstays of treatment, although novel treatment modalities are currently under investigation for potential roles in treatment of this disease.

CONCLUSION

This review aims to describe the clinical presentation and progression of the various forms of HSA in dogs and cats as well as to provide a systematic review of the veterinary literature with a focus on the various published treatment options and associated outcomes.

Development and validation of a multivariable model and online decision-support calculator to aid in preoperative discrimination of benign from malignant splenic masses in dogs

OBJECTIVE

To develop a multivariable model and online decision-support calculator to aid in preoperative discrimination of benign from malignant splenic masses in dogs.

ANIMALS

522 dogs that underwent splenectomy because of splenic masses.

PROCEDURES

A multivariable model was developed with preoperative clinical data obtained retrospectively from the records of 422 dogs that underwent splenectomy. Inclusion criteria were the availability of complete abdominal ultrasonographic examination images and splenic histologic slides or histology reports for review. Variables considered potentially predictive of splenic malignancy were analyzed. A receiver operating characteristic curve was created for the final multivariable model, and area under the curve was calculated. The model was externally validated with data from 100 dogs that underwent splenectomy subsequent to model development and was used to create an online calculator to estimate probability of splenic malignancy in individual dogs.

RESULTS

The final multivariable model contained 8 clinical variables used to estimate splenic malignancy probability: serum total protein concentration, presence (vs absence) of ≥ 2 nRBCs/100 WBCs, ultrasonographically assessed splenic mass diameter, number of liver nodules (0, 1, or ≥ 2), presence (vs absence) of multiple splenic masses or nodules, moderate to marked splenic mass inhomogeneity, moderate to marked abdominal effusion, and mesenteric, omental, or peritoneal nodules. Areas under the receiver operating characteristic curves for the development and validation populations were 0.80 and 0.78, respectively.

CONCLUSIONS AND CLINICAL RELEVANCE

The online calculator (T-STAT.net or T-STAT.org) developed in this study can be used as an aid to estimate the probability of malignancy in dogs with splenic masses and has potential to facilitate owners' decisions regarding splenectomy.

Serum angiopoietin-2 levels in dogs with splenic haemangiosarcoma, haemangioma, and splenitis

Haemangioma (HA) and haemangiosarcoma (HSA) are among the most common splenic neoplasms in dogs. The survival time in splenic HSA is short, probably due to the lack of proper biological markers allowing early detection. We investigated the serum angiopoietin-2 (Ang-2) concentrations in 9 healthy dogs and 40 dogs with abnormal splenic masses. The Ang-2 concentration differences were further compared in healthy dogs, dogs with splenitis, splenic HA and HSA. The results showed that the Ang-2 level in healthy dogs was significantly lower than in the splenitis and splenic HA cases. Moreover, the Ang-2 level was significantly higher in splenic HA than in splenic HSA. Conversely, no significant differences in Ang-2 level were recorded between healthy and splenic HSA dogs, and between splenitis and splenic neoplasms (HA and HSA). No significant correlations were observed between the Ang-2 level and (i) the clinical stage, (ii) histological growth pattern, and (iii) median survival time of splenic HSA dogs. In conclusion, serum Ang-2 concentration is a potentially useful biological marker for the discrimination of dogs with splenitis and splenic HA, as well as for the differentiation of splenic HA from its malignant form, HSA.

Partial Gastrectomy at the Time of Splenectomy in Two Dogs With Splenic Neoplasia and Gastric Involvement

Splenic malignancies are reported in 30%-76% of dogs presenting with splenic masses, and splenectomy is the cornerstone in their management. However, long term prognosis is guarded due to the high rates of distant metastases reported both for HSA and nonangiogenic nonlymphomatous sarcomas. Metastases from splenic tumors usually occur to regional lymph nodes, liver, omentum, and lungs. These case series aim to describe 2 cases of splenic neoplasia with gastric involvement and report the surgical technique and outcomes associated with the condition. Two mixed-breed dogs were referred for a splenic mass and underwent explorative celiotomy. In both cases, the splenic mass was firmly attached to the gastric wall, and splenectomy with concurrent partial gastrectomy was thus performed. In case 1, liver lobectomy due to a hepatic mass was also performed. In case 2, the regional nodes were also excised due to lymphoadenomegaly. Both dogs recovered uneventfully from surgery and were discharged from the hospital at 72 and 96 hours. Histopathological examination was costent with splenic undifferentiated sarcoma and hepatic adenocarcinoma in one dog. The other dog had a diagnosis of malignant fibrous histiocytoma with nodal metastases. Neoplastic invasion of the stomach was histologically confirmed in both dogs. Adjuvant chemotherapy was refused, and both dogs were euthanized due to tumor progression at 71 and 58 days, respectively. According to our results, splenectomy with concurrent gastrectomy is feasible in dogs with splenic tumours involving the gastric wall. However, long term prognosis is poor, as previously reported for metastatic splenic sarcomas.

Refining the "double two-thirds" rule: Genotype-based breed grouping and clinical presentation help predict the diagnosis of canine splenic mass lesions in 288 dogs

Prediction of the likely histopathological diagnosis of canine splenic masses can guide appropriate decision-making. This study explores the predictive effect of breed and clinical presentation on the diagnosis of a canine splenic mass. Records from the Royal Veterinary College, United Kingdom (2007-2017) were reviewed. Dogs with a histopathologic or cytologic diagnosis from a splenic mass, or imaging findings consistent with disseminated metastatic disease, were included. Signalment, physical examination, haematology results, imaging findings and pathology reports were recorded. Breeds were grouped according to several permutations of their phenotype and then by clustering of breeds based on single nucleotide polymorphism analysis. Binary logistic regression was performed to identify predictors of malignancy and haemangiosarcoma. Two hundred and eighty-eight dogs were identified: 27% female and 63% male, 21% entire and 79% neutered; German Shepherd was the most common breed (11%). Median age was 10 years and median bodyweight 25 kg. Thirty-eight percent of dogs presented with haemoabdomen; a splenic mass was found incidentally in 28%. Sixty percent had a malignant tumour of which haemangiosarcoma comprised 66%. On multivariable analysis, genotype-based breed group (P = .004), haemoabdomen (P < .001) and neutrophil count (P = .025) predicted malignancy, and genotype-based breed group (P < .001) and haemoabdomen (P < .001) predicted haemangiosarcoma. Genotype-based breed group and occurrence of haemoabdomen may have predictive value to diagnose malignant splenic masses and more specifically haemangiosarcoma. The effect of genotype-based breed grouping was a superior predictor of the diagnosis of a canine splenic mass lesion compared with all phenotype-based groupings tested.

Clinical relevance of splenic nodules or heterogeneous splenic parenchyma assessed by cytologic evaluation of fine-needle samples in 125 dogs (2011-2015)

Background

Splenic nodules and heterogeneous parenchyma are seen frequently in abdominal ultrasound examinations of dogs, but the clinical importance of these lesions remains unclear.

Objectives

To determine whether specific ultrasonographic findings correlate with clinically relevant cytologic diagnoses and determine what sonographic features are correlated with these diagnoses. Another objective was to develop a scoring rubric to help clinicians make decisions on whether or not certain ultasonographic findings of the spleen warrant evaluation by fine‐needle cytology.

Animals

One‐hundred twenty‐five adult client‐owned dogs with ultrasonographically identified splenic nodules, heterogeneous parenchyma, or both.

Methods

Medical records were retrospectively searched for ultrasound‐guided splenic fine‐needle cytology reports. Ultrasonographic images were assessed for nodule number, size, echogenicity and distal enhancement, degree of splenic heterogeneity, and peritoneal fluid. Dogs were divided into 2 groups: those with clinically important or clinically irrelevant cytologic findings. Potentially useful and discriminatory ultrasonographic findings were identified by statistical analysis, and the most useful findings were used to generate the scoring rubric.

Results

The clinically important group included 25 of 125 dogs (22 malignancies, 3 suppurative inflammation). Splenic nodules 1‐2 cm in diameter, peritoneal fluid, and >1 targetoid nodule were associated with clinically important cytologic findings. Receiver operator characteristic analysis showed that the scoring rubric was useful for identifying dogs in the clinically important group.

Conclusions and Clinical Importance

Splenic fine‐needle cytologic findings identified a clinically relevant diagnosis in 20% of dogs, and larger nodule size, number of targetoid lesions, and presence of peritoneal fluid increase the likelihood of detection of clinically important disease.

Understanding the Efficiency of Splenic Hemangiosarcoma Diagnosis Using Monte Carlo Simulations

Hemangiosarcoma is a common neoplasm of the spleen in older dogs. However, diagnosis is complicated by necrosis and hemorrhage, which can mimic a number of benign processes. Currently, there is no consensus about the number of sections pathologists should examine to rule out hemangiosarcoma. To answer this question, we examined 413 histopathologic sections from 50 cases of canine hemangiosarcoma (mean: 8.1 sections per case; range, 5-14). Each section had the presence or absence of hemangiosarcoma determined by 2 board-certified anatomic pathologists. Then, 100 Monte Carlo simulations were performed, randomly selecting sections from each case 10 000 times and the results averaged. These simulations suggest that examination of 5 sections from a spleen with hemangiosarcoma yields a 95.02% chance of diagnosing hemangiosarcoma, while examination of 10 sections yields a 98.59% chance of diagnosis when hemangiosarcoma is in fact present. The data emphasize the need to submit the entire spleen for histopathologic examination in suspected cases of hemangiosarcoma and suggest that 5 sections obtained by a trained individual are likely sufficient for diagnosis.

Evaluation of Nodular Splenic Lesions in 370 Small-Breed Dogs (<15 kg)

Three hundred seventy small-breed dogs (<15 kg) undergoing splenectomy for the presence of nodular splenic lesions were evaluated in a retrospective study to assess associations with breeds, malignancy, hemoperitoneum, and median survival time compared with previous studies. Data analyzed included signalment, histopathologic diagnosis, presence or absence of hemoperitoneum, breed associations, and survival times. In the current study, 44% (163/370) of dogs had nonneoplastic splenic lesions and 56% (207/370) had neoplastic lesions. Hemangiosarcoma was present in 27% (100/370) of splenic lesions. Hemoperitoneum was present in 31% (115/370) of dogs, and of this population, 66% (76/115) had malignant splenic lesions. The most common breeds were miniature schnauzers, dachshunds, and beagles, with beagles exhibiting a positive association with malignancy. The presence of hemoperitoneum was associated with malignancy. Distribution for nodular splenic lesions, correlation of hemoperitoneum to malignancy, and median survival time were similar to previous reports in large-breed dogs. Small-breed dogs who present with hemoperitoneum are 2.6 times more likely to have a diagnosis of a malignant splenic lesion. The most common small-breed dogs with nodular splenic lesions were miniature schnauzers, dachshunds, and beagles. Beagles and small-breed terriers were more likely to have malignant splenic lesions, and small-breed terriers were more likely to present with hemoperitoneum.

Development and validation of a hemangiosarcoma likelihood prediction model in dogs presenting with spontaneous hemoabdomen: The HeLP score

OBJECTIVE

To calculate a risk prediction model for hemangiosarcoma (HSA) diagnosis in dogs presenting with nontraumatic hemoabdomen.

DESIGN

Retrospective multicenter observational cohort study enrolling dogs presented 2003-2016.

SETTING

Five academic veterinary medical centers.

ANIMALS

A total of 406 dogs with nontraumatic hemoabdomen as the presenting complaint that underwent surgical exploration or necropsy and received a histological diagnosis. Overall, 219 dogs from 3 centers provided the data for model construction, and 187 dogs from 2 centers provided the population for external validation.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The risk score was modeled on 4 predictors: bodyweight (P = 0.01), total plasma protein (P < 0.01), platelet count (P < 0.01), and thoracic radiograph findings (P = 0.02). The incidence of HSA diagnosis was 36%, 76%, and 96% in the low risk (≤40), medium risk (41-55), and high risk (>55) score groups, respectively. The risk score AUROC was 0.85 (95% CI 0.79-0.90) on the construction population, and 0.77 (95% CI 0.70-0.84) on the validation population.

CONCLUSIONS

The risk of HSA diagnosis in dogs presenting with nontraumatic hemoabdomen could be predicted using a simple risk score, which could aid in identification and treatment of dogs at lower risk for this diagnosis.

Prevalence, distribution, and clinical characteristics of hemangiosarcoma-associated skeletal muscle metastases in 61 dogs: A whole body computed tomographic study

BACKGROUND

Skeletal muscle metastases (SMMs) have been described sporadically in canine oncology.

HYPOTHESIS/OBJECTIVES

To determine the prevalence, localization, and clinical signs of SMMs associated with hemangiosarcoma (HSA) in a population of dogs presented for whole body computed tomography (CT).

ANIMALS

Dogs with a histologically confirmed HSA and a tissue core specimen or fine needle aspirate of suspected metastatic lesions were included in the study.

METHODS

Retrospective study. Dogs with a final diagnosis of visceral or muscular HSA that underwent whole body CT scan were enrolled in the study. Final diagnosis of primary tumor and SMMs was reached by histology, cytology, or both. Signalment, clinical signs, localization of the primary lesion, and metastases characteristics were reviewed.

RESULTS

Sixty-one dogs met the inclusion criteria. Skeletal muscle metastases were detected in 15 dogs (24.6%) and all of these dogs had also metastases in ≥1 sites. Presence of SMMs was significantly higher in males but was not significantly related to age, neuter status, breed, localization, and dimensions of the primary tumor. Nine of 15 (60.0%) dogs with SMMs showed lameness or reluctance to move whereas these signs were not recorded in any of the 42 dogs without SMMs (P < .001).

CONCLUSION AND CLINICAL IMPORTANCE

Prevalence of SMMs in our population of dogs with HSA was higher in comparison to previous studies in the human and veterinary medical literature. Whole body CT is recommended for staging of dogs with HSA, because SMMs could be missed by clinical examination and traditional diagnostic imaging modalities.

Presurgical assessment of splenic tumors in dogs: a retrospective study of 57 cases (2012-2017)

The purpose of this study was to evaluate the clinical and imaging characteristics of canine splenic tumors and to establish guidelines for the presurgical assessment of splenic tumors in dogs. Fifty-seven dogs that underwent total splenectomy for the treatment of splenic tumors were evaluated by examining medical records, hematologic results, diagnostic imaging results, and histopathologic results. The maximum lesion size from ultrasonography was significantly different between malignant and benign tumors (p = 0.002). There was a correlation between tumor margination and type of splenic tumors (p = 0.045). Precontrast lesion attenuation on computed tomography was significantly different between splenic malignant and benign tumors (p = 0.001). The mean ± SD precontrast lesion attenuation of malignant tumors was 40.3 ± 5.9 Hounsfield units (HU), and for benign tumors, it was 52.8 ± 6.8 HU. In conclusion, some variables of the imaging examination could be used to distinguish the type of splenic tumor. Based on the study results, using a diagnostic flowchart would be effective in increasing the survival rate of patients with splenic malignant tumors. In addition, fine needle aspiration or magnetic resonance imaging prior to surgical exploration and histopathologic examination may be useful in achieving a more accurate diagnosis.

Histopathologic characteristics of biopsies from dogs undergoing surgery with concurrent gross splenic and hepatic masses: 125 cases (2012-2016)

Objective

To investigate the histopathologic characteristics of concurrent splenic and liver masses in dogs undergoing splenectomy and liver mass biopsy/resection. Medical records of 125 client-owned dogs found to have splenic mass or masses and a liver mass or masses during surgery were examined. Signalment (age, sex, breed), body weight, and results of histopathology were recorded for all dogs.

Results

Twenty-seven percent (34/125) of the dogs in this study had no evidence of malignancy in either the liver or the spleen. Sixty of 125 dogs (48.0%) had malignancy in the spleen and liver, and 56 (56/60, 93.3%) of those dogs had the same malignancy in both organs. Signalment was similar to that in other reports of splenic pathology. In this clinical population of dogs, 27% of dogs with concurrent gross splenic and liver masses discovered intraoperatively had benign lesions in both locations and therefore had a favorable prognosis.

Electronic supplementary material

The online version of this article (10.1186/s13104-018-3220-1) contains supplementary material, which is available to authorized users.

A comparison of microRNA expression profiles from splenic hemangiosarcoma, splenic nodular hyperplasia, and normal spleens of dogs

Background

Splenic masses are common in older dogs; yet diagnosis preceding splenectomy and histopathology remains elusive. MicroRNAs (miRNAs) are short, non-coding RNAs that play a role in post-transcriptional regulation, and differential expression of miRNAs between normal and tumor tissue has been used to diagnose neoplastic diseases. The objective of this study was to determine differential expression of miRNAs by use of RNA-sequencing in canine spleens that were histologically confirmed as hemangiosarcoma, nodular hyperplasia, or normal.

Results

Twenty-two miRNAs were found to be differentially expressed in hemangiosarcoma samples (4 between hemangiosarcoma and both nodular hyperplasia and normal spleen and 18 between hemangiosarcoma and normal spleen only). In particular, mir-26a, mir-126, mir-139, mir-140, mir-150, mir-203, mir-424, mir-503, mir-505, mir-542, mir-30e, mir-33b, mir-365, mir-758, mir-22, and mir-452 are of interest in the pathogenesis of hemangiosarcoma.

Conclusions

Findings of this study confirm the hypothesis that miRNA expression profiles are different between canine splenic hemangiosarcoma, nodular hyperplasia, and normal spleens. A large portion of the differentially expressed miRNAs have roles in angiogenesis, with an additional group of miRNAs being dysregulated in vascular disease processes. Two other miRNAs have been implicated in cancer pathways such as PTEN and cell cycle checkpoints. The finding of multiple miRNAs with roles in angiogenesis and vascular disease is important, as hemangiosarcoma is a tumor of endothelial cells, which are driven by angiogenic stimuli. This study shows that miRNA dysregulation is a potential player in the pathogenesis of canine splenic hemangiosarcoma.

ASSOCIATIONS BETWEEN DUAL-PHASE COMPUTED TOMOGRAPHY FEATURES AND HISTOPATHOLOGIC DIAGNOSES IN 52 DOGS WITH HEPATIC OR SPLENIC MASSES

Ability to noninvasively differentiate malignant from nonmalignant abdominal masses would aid clinical decision making. The aim of this retrospective, cross-sectional study was to identify features in dual-phase computed tomographic (CT) studies that could be used to distinguish malignant from nonmalignant hepatic and splenic masses in dogs. Medical records were searched for dogs that had an abdominal dual-phase CT examination, a hepatic or splenic mass, and subsequent histopathologic diagnosis. Computed tomographic images for all included dogs were acquired prior to and <30 s (early phase) and >60 s (delayed phase) after intravenous contrast administration. Fifty-two dogs with 55 masses were studied: 24 hepatic, including 14 (58%) malignant and 10 (42%) non-malignant; 31 splenic, including 18 (58%) malignant and 13 (42%) nonmalignant. There was substantial overlap in the pre- and postcontrast CT features of malignant and nonmalignant hepatic and splenic masses. Regardless of histologic diagnosis, hepatic masses most frequently showed marked, generalized enhancement in early phase images that persisted in the delayed phase. Splenic hemangiosarcoma and nodular hyperplastic lesions most frequently showed marked, generalized enhancement in early phase images that persisted in delayed images whereas most splenic hematomas had slight enhancement in early phase images. All splenic hematomas and 77% of the hemangiosarcomas had contrast accumulation compatible with active hemorrhage. There were no other significant differences in quantitative or categorical CT data between malignant and nonmalignant hepatic or splenic masses. Dual-phase CT of dogs with hepatic or splenic masses provides limited specific diagnostic information.