Diagnosing appendicular osteosarcoma with ultrasound-guided fine-needle aspiration: 36 cases

Telangiectatic osteosarcoma in four dogs: Cytologic, histopathologic, cytochemical, and immunohistochemical findings

Telangiectatic osteosarcoma is a rare variant of osteosarcoma histologically and clinically similar to hemangiosarcoma (HSA). This case series describes the imaging and cytologic features of four histologically confirmed telangiectatic osteosarcomas, including the use of cytochemical stains. Alkaline phosphatase (ALP) was applied to Wright-Giemsa-stained cytology slides, and Factor VIII immunohistochemistry was evaluated. Cytologic characteristics included atypical mesenchymal cells with evidence of acute and chronic hemorrhage. Telangiectatic osteosarcoma cases had positive ALP cytochemical staining, while control HSA cases were negative. Factor VIII immunohistochemistry was negative in telangiectatic osteosarcoma and positive in HSA. Cytologic diagnosis of telangiectatic osteosarcoma with positive ALP cytochemical staining can help differentiate this neoplasm from HSA.

Characterization of alkaline phosphatase cytochemistry in canine neoplastic and non-neoplastic pulmonary mass aspirates

BACKGROUND

Distinguishing primary and secondary pulmonary neoplasms can be challenging via cytology, and a rapid, inexpensive diagnostic tool to differentiate these neoplasms is unavailable. Alkaline phosphatase cytochemistry (ALP-CC) has been used to identify primary pulmonary carcinomas in human patients, and we hypothesized it could be applied to canine lung aspirates.

OBJECTIVE

We aimed to characterize ALP-CC expression in fine-needle aspirate (FNA) samples of canine pulmonary neoplastic and non-neoplastic tumors.

METHODS

A retrospective case search was conducted to identify cases with contemporaneous cytology and histopathology reports from pulmonary lesions, including neoplastic and non-neoplastic etiologies. Slides prepared from pulmonary aspirates were stained for ALP-CC activity, and the percentage of ALP-CC-positive primary pulmonary epithelial tumors was determined. To characterize the ALP-CC expression in non-neoplastic cellular constituents of pulmonary FNA samples, mesothelial cells were also evaluated.

RESULTS

Forty-eight canine cases met the inclusion criteria. ALP-CC-positive cells were seen in both neoplastic and non-neoplastic lesions. In non-neoplastic lesions, pulmonary epithelial cells were ALP-CC positive. Eighty-nine percent of primary pulmonary epithelial neoplasms were ALP-CC positive, and no ALP-CC positivity was noted in mesothelial cells. ALP-CC-positive neoplastic cells were seen in a metastatic amelanotic melanoma.

CONCLUSIONS

Primary pulmonary epithelial neoplasms are frequently ALP-CC positive, but such positivity is not restricted to this tumor type. Non-neoplastic pulmonary epithelial cells can be ALP-CC positive, whereas mesothelial cells are negative.

Potential Seeding From Fine-Needle Aspiration of an Axial Osteosarcoma: A Case Report

This report describes the first potential case of seeding after fine-needle aspiration (FNA) of a rib osteosarcoma in a dog. An 8-year-old, 28-kg female spayed Golden Retriever was presented to her primary veterinarian with a 3-week history of a 3-cm firm, unpainful, immobile mass arising from the 9th rib. The mass was aspirated and submitted for cytological examination. A subcutaneous nodule developed several days after the FNA was performed in a location immediately overlying but distinct from the primary rib tumor on palpation. Both the primary mass and the newly diagnosed subcutaneous nodule were biopsied and were consistent with an osteosarcoma. Although it cannot be ruled out that the subcutaneous lesion was metastatic, seeding was a reasonable explanation based on where the new mass was located and how quickly it appeared after the FNA was performed. The aim of this case report was to describe the possibility of tumor seeding during FNA for osteosarcoma. It is the authors' opinion that utility of cytological diagnosis of bone tumors outweighs the risk of possible seeding and should continue to be used as a routine diagnostic test for the diagnosis of aggressive bone lesions.

Recent Advances in the Discovery of Biomarkers for Canine Osteosarcoma

Canine osteosarcoma (OSA) is an aggressive malignancy that frequently metastasizes to the lung and bone. Not only has there been essentially no improvement in therapeutic outcome over the past 3 decades, but there is also a lack of reliable biomarkers in clinical practice. This makes it difficult to discriminate which patients will most benefit from the standard treatment of amputation and adjuvant chemotherapy. The development of reliable diagnostic biomarkers could aid in the clinical diagnosis of primary OSA and metastasis; while prognostic, and predictive biomarkers could allow clinicians to stratify patients to predict response to treatment and outcome. This review summarizes biomarkers that have been explored in canine OSA to date. The focus is on molecular biomarkers identified in tumor samples as well as emerging biomarkers that have been identified in blood-based (liquid) biopsies, including circulating tumor cells, microRNAs, and extracellular vesicles. Lastly, we propose future directions in biomarker research to ensure they can be incorporated into a clinical setting.

A Holistic Approach to Bone Tumors in Dogs and Cats: Radiographic and Histologic Correlation

The skeletal system is a common site for neoplasia in dogs and cats, and primary bone tumors may develop from any of the mesenchymal tissues present in bone. Imaging and histopathology are routinely used in the diagnosis of bone tumors, and the 2 techniques are highly complementary. While imaging may be highly suggestive of a specific diagnosis and treatment may be instituted based on this, definitive diagnosis requires histopathology of either incisional or excisional biopsies or an amputation specimen. However, there are a number of diagnostic dilemmas when the pathologist interprets bone biopsy samples, such as distinguishing reactive bone and tumor bone, fracture callus and tumor bone, different benign fibro-osseous lesions, and different types of bone sarcoma. This review outlines the characteristic radiographic and histologic changes associated with these diagnostic problems to aid in resolving them. When a holistic approach is taken to evaluation of the signalment, history, and clinical, radiologic, and microscopic features, a diagnosis may be possible. The pathologist is greatly assisted in the interpretation of bone samples by having access to imaging and should routinely request either the images or the imaging reports if they are not received from submitting veterinarians.

Outcome and prognosis for canine appendicular osteosarcoma treated with stereotactic body radiation therapy in 123 dogs

Canine appendicular osteosarcoma is commonly treated with limb amputation; however, limb-sparing options are frequently desired or necessary for a subset of patients. We evaluated 123 patients and 130 sites treated with stereotactic body radiation therapy (SBRT). Eighty-two out of 98 dogs (84%) had maximum lameness improvement at a median of 3 weeks for a median of 6 months duration. Histopathologic evaluation of available samples from amputation or necropsy revealed >80% tumor necrosis in 50% of limbs consistent with local disease control. Of evaluable patients, 41% fractured and 21% pursued an amputation after treatment. Fine needle aspirate (n = 52) and needle core biopsy (n = 28) did not result in increased fracture risk compared to those without tumor sampling (n = 50). Median survival time (MST) was 233 days and time to first event was 143 days. Gross tumor volume and planned target volume were significantly inversely associated with survival and tumor location was significantly associated with survival. Dogs with salvage amputation had a significantly longer MST compared to those without (346 vs 202 days; P = .04). The presence of metastatic disease at the time of treatment in 15 dogs did not significantly impact survival time (200 vs 237 days without metastasis; P = .58). Skin side effects correlated significantly with dose with 33% of patients with acute grade 3 effects developing consequential late grade 3 effects. While SBRT improves lameness in most patients, further investigation is needed to identify candidates with minimal early fracture risk prior to initiating therapy.

A comparison of risk factors for metastasis at diagnosis in humans and dogs with osteosarcoma

Background

Canine osteosarcoma (OS) is a relevant spontaneous model for human OS. Identifying similarities in clinical characteristics associated with metastasis at diagnosis in both species may substantiate research aimed at using canine OS as a model for identifying mechanisms driving distant spread in the human disease.

Methods

This retrospective study included dog OS cases from three academic veterinary hospitals and human OS cases from the Surveillance, Epidemiology, and End Results program. Associations between clinical factors and metastasis at diagnosis were estimated using logistic regression models.

Results

In humans, those with trunk tumors had higher odds of metastasis at diagnosis compared to those with lower limb tumors (OR = 2.38, 95% CI: 1.51, 3.69). A similar observation was seen in dogs with trunk tumors compared to dogs with forelimb tumors (OR = 3.28, 95% CI 1.36, 7.50). Other associations were observed in humans but not in dogs. Humans aged 20‐29 years had lower odds of metastasis at diagnosis compared to those aged 10‐14 years (OR = 0.67, 95% CI: 0.47, 0.96); every 1‐cm increase in tumor size was associated with a 6% increase in the odds of metastasis at diagnosis (95% CI: 1.04, 1.08); compared to those with a white, non‐Hispanic race, higher odds were observed among those with a black, non‐Hispanic race (OR: 1.51, 95% CI: 1.04, 2.16), and those with a Hispanic origin (OR 1.35, 95% CI: 1.00, 1.81).

Conclusion

A common mechanism may be driving trunk tumors to progress to detectable metastasis prior to diagnosis in both species.

Comparative Assessment of the Accuracy of Cytological and Histologic Biopsies in the Diagnosis of Canine Bone Lesions

BACKGROUND

Osteosarcoma (OSA) should be differentiated from other less frequent primary bone neoplasms, metastatic disease, and tumor-like lesions, as treatment and prognosis can vary accordingly. Hence, a preoperative histologic diagnosis is generally preferred. This requires collection of multiple biopsies under general anesthesia, with possible complications, including pathological fractures. Fine-needle aspiration cytology would allow an earlier diagnosis with a significant reduction of discomfort and morbidity.

HYPOTHESIS/OBJECTIVES

The aim of this study was to compare the accuracy of cytological and histologic biopsies in the diagnosis of canine osteodestructive lesions.

ANIMALS

Sixty-eight dogs with bone lesions.

METHODS

Retrospective study. Accuracy was assessed by comparing the former diagnosis with the final histologic diagnosis on surgical or post-mortem samples or, in the case of non-neoplastic lesions, with follow-up information.

RESULTS

The study included 50 primary malignant bone tumors (40 OSAs, 5 chondrosarcomas, 2 fibrosarcomas, and 3 poorly differentiated sarcomas), 6 carcinoma metastases, and 12 non-neoplastic lesions. Accuracy was 83% for cytology (sensitivity, 83.3%; specificity, 80%) and 82.1% for histology (sensitivity, 72.2%; specificity, 100%). Tumor type was correctly identified cytologically and histologically in 50 and 55.5% of cases, respectively.

CONCLUSIONS AND CLINICAL IMPORTANCE

The accuracy of cytology was similar to histology, even in the determination of tumor type. In no case was a benign lesion diagnosed as malignant on cytology. This is the most important error to prevent, as treatment for malignant bone tumors includes aggressive surgery. Being a reliable diagnostic method, cytology should be further considered to aid decisions in the preoperative setting of canine bone lesions.

Cytology of Bone

Cytology of bone is a useful diagnostic tool. Aspiration of lytic or proliferative lesions can assist with the diagnosis of inflammatory or neoplastic processes. Bacterial, fungal, and protozoal organisms can result in significant osteomyelitis, and these organisms can be identified on cytology. Neoplasms of bone including primary bone tumors such as osteosarcoma, chondrosarcoma, fibrosarcoma, synovial cell sarcoma, and histiocytic sarcoma and tumors of bone marrow including plasma cell neoplasia and lymphoma and metastatic neoplasia can result in significant bone lysis or proliferation and can be diagnosed effectively with cytology.

An Unusual Case of Metastatic Seminoma in a Dog

An 8 yr old, reportedly castrated male Boston terrier presented with a history of generalized hyperesthesia and intermittent shifting leg lameness. Physical examination revealed a caudal abdominal mass and bilateral shoulder pain. A complete blood count, serum biochemistry panel, and urinalysis were unremarkable. Thoracic radiographs demonstrated bony proliferation and lysis of the third sternebra, an expansile lesion of the left tenth rib, and lucency in both proximal humeral metaphyses. Abdominal radiographs and ultrasound revealed a soft tissue mass within the caudoventral right abdomen. Ultrasonography also revealed an enlarged lymph node within the right retroperitoneal space. Exploratory laparotomy identified the mass as a retained testicle. A cryptorchidectomy, lymph node biopsy, and bilateral percutaneous core biopsies of the proximal humeri were performed. Histopathologic examination revealed malignant seminoma of the testicle with metastasis to lymph node and bone. Adjuvant chemotherapy was recommended, but it was declined by the owner. All follow-up was lost. This case highlights a unique case for causative hyperesthesia secondary to a novel site of metastasis from malignant seminoma. Metastasis to bone has not been reported in humans or dogs and represents a very unusual and aberrant variant of the normally relatively benign biological behavior of seminoma in the dog.

Clinical outcome of 42 dogs with scapular tumors treated by scapulectomy: a Veterinary Society of Surgical Oncology (VSSO) retrospective study (1995-2010)

OBJECTIVE

To report signalment, clinical signs, preoperative staging tests, histologic diagnosis, surgical, and oncologic outcomes including postoperative limb use, in dogs with scapular tumors treated by scapulectomy.

STUDY DESIGN

Retrospective case series

ANIMALS

Dogs (n = 42) with scapular tumors.

METHODS

Medical records (1995-2010) from 6 hospitals were searched for dogs with scapular tumors treated by scapulectomy. Data retrieved were: signalment, weight, percentage of scapula removed, histologic diagnosis, postoperative limb use, adjunctive therapy, disease free interval (DFI), and survival time (ST). Individual variables were modeled with a Cox proportional hazard model accounting for censoring to determine risk factors for decreased DFI and ST. For categorical variables, Kaplan-Meier survival plots as well as mean and median survival times (MSTs) were calculated.

RESULTS

Subtotal scapulectomy was performed in 18 dogs (42.9%). Osteosarcoma (OSA) was diagnosed in 27 dogs (64.3%). Limb use was evaluated immediately after surgery in 41 dogs. Information on limb use at other times (1, 2, 3, and >3 months) postoperatively was also available for some dogs and was good to excellent overall. Only adjunctive chemotherapy had a positive significant effect on DFI (P = .00011) and ST (P = .0003).

CONCLUSION

Canine scapular tumors can be treated effectively by scapulectomy and limb use is fair to excellent for most dogs. OSA was the most common scapular tumor. Overall prognosis for scapular OSA is similar to appendicular OSA at other sites and use of adjunctive chemotherapy prolonged the overall DFI and MST.

Using cytology to increase small animal practice revenue

Diagnostic cytology is a useful, noninvasive test with practical foundations in high-quality medicine and applications to practice building. Cytology will generate practice revenue whether assessed in-house or sent to a clinical pathologist. Thorough in-house evaluation is adequate in some cases, but expert opinion is important in many cases. Specimen slides should at least be reviewed in-house for assessment of cellularity and potential artifacts before submission to a reference laboratory. Reference laboratories also provide special stains and advanced molecular diagnostics to help further characterize many neoplastic processes, search for organisms, identify pigments, and address other important aspects of the lesion.

The impact of pamidronate and chemotherapy on survival times in dogs with appendicular primary bone tumors treated with palliative radiation therapy

OBJECTIVE

To assess survival times in dogs that received palliative radiation therapy (RT) alone, and in combination with chemotherapy, pamidronate, or both for primary appendicular bone tumors and determine whether the addition of these adjunctive therapies affects survival.

STUDY DESIGN

Retrospective case series.

ANIMALS

Dogs (n = 50) with primary appendicular bone tumors.

METHODS

Dogs were divided into the following treatment groups: RT alone, RT + chemotherapy, RT+ pamidronate, and RT+ chemotherapy + pamidronate. Dogs were considered for analysis if they had a known euthanasia date or follow-up data were available for at least 120 days from the time of diagnosis. Survival time was defined as the time from admission to euthanasia. Cox proportional hazard models and Kaplan-Meier survival functions were used. A P value of less than .05 was considered significant.

RESULTS

Fifty dogs were considered for survival analysis. Median survival times (MSTs) were longest for dogs receiving RT and chemotherapy (307 days; 95% CI: 279, 831) and shortest in dogs receiving RT and pamidronate (69 days; 95% CI: 47, 112 days). The difference in MST between dogs who received pamidronate and those who did not in this population was statistically significant in a univariate (P = .039) and multivariate analysis (P = .0015). The addition of chemotherapy into any protocol improved survival (P < .001).

CONCLUSIONS

Chemotherapy should be recommended in addition to a palliative RT protocol to improve survival of dogs with primary appendicular bone tumors. When combined with RT ± chemotherapy, pamidronate decreased MST and should not be included in a standard protocol.

Foreign body reaction to a retained surgical sponge (gossypiboma) mimicking an implant associated sarcoma in a dog after a tibial plateau levelling osteotomy

A dog was presented with the complaint of an acute onset left pelvic limb lameness three years after a right tibial plateau levelling osteotomy had been performed. Radiographs taken at the time of presentation showed signs that were consistent with a diagnosis of an implant associated sarcoma. At revision surgery, a retained surgical sponge was identified, leading to a diagnosis of a gossypiboma. This is the first reported case of a gossypiboma as a complication of a tibial plateau levelling osteotomy surgery.

Getting to the point: indications for fine-needle aspiration of internal organs and bone

The technique of fine-needle biopsy (fine-needle aspiration or fine-needle fenestration) for cytologic evaluation can be extended to many sites beyond the traditional lymph node and skin. Intra-abdominal, intrathoracic, and bone lesions can be easily and rapidly evaluated cytologically. Percutaneous fine-needle aspiration and fine-needle fenestration are useful, accurate, and inexpensive techniques with a rapid turnaround time, and outpatient applicability. For most pets, these minimally invasive techniques do not require anesthesia or analgesia. Although risks are inherent with any invasive procedure, complications are uncommon even with visceral and intrathoracic fine-needle biopsy. Attention to appropriate technique and close patient monitoring minimize the morbidity and improve the diagnostic utility. The low cost, low risk, minimal invasiveness, and high diagnostic yield make fine-needle biopsy particularly attractive to clients. In combination with ultrasound guidance and newer staining techniques, these diagnostic procedures are invaluable to the veterinary clinician.

A Novel Method of Core Aspirate Cytology Compared to Fine-Needle Aspiration for Diagnosing Canine Osteosarcoma

There is little information in veterinary literature regarding the diagnostic accuracy of aspirate cytology for the diagnosis of canine osteosarcoma (OSA). The authors compared the diagnostic accuracy of a novel method of cytologic collection, termed core aspirate cytology (CA), with fine needle aspiration (FNA) and histopathology in 27 dogs with lytic and/or proliferative bone lesions. Alkaline phosphatase (ALP) staining was performed to confirm the diagnosis of OSA cytologically. OSA was accurately diagnosed in 85% and 95% of FNA and CA, respectively. ALP staining was 100% sensitive for the diagnosis of OSA. CA using a bone marrow biopsy needle allowed for penetration of cortical bone and aspirate cytology with a larger bore needle than FNA; however, there was no significant difference in diagnostic accuracy between techniques. Aspirate cytology with ALP staining was a safe, accurate, and minimally invasive diagnostic test for the evaluation of suspected OSA lesions in dogs.

Predictors of outcome in dogs treated with adjuvant carboplatin for appendicular osteosarcoma: 65 cases (1996-2006)

OBJECTIVE

To determine outcomes and prognostic factors for those outcomes in dogs with appendicular osteosarcoma treated with curative-intent surgery and adjuvant carboplatin.

DESIGN

Retrospective case series.

ANIMALS

65 client-owned dogs with appendicular osteosarcoma and no evidence of gross metastatic disease at the time of diagnosis.

PROCEDURES

Medical records of dogs that underwent limb amputation or distal ulnectomy and adjuvant carboplatin treatment for appendicular osteosarcoma were reviewed. Adverse effects of chemotherapy and findings regarding preoperative biopsy specimens and postoperative diagnostic imaging were recorded. Signalment, clinical history, and chemotherapy variables were evaluated for associations with outcome. Histologic grade and other variables were evaluated for association with outcome for 38 tumors that were retrospectively graded.

RESULTS

The median disease-free interval was 137 days (95% confidence interval [CI], 112 to 177 days). Median survival time was 277 days (95% CI, 203 to 355 days). The 1-, 2-, and 3-year survival rates were 36%, 22%, and 19%, respectively. None of the chemotherapy variables were associated with outcome. Preoperative proteinuria was the only clinical variable associated with poor outcome. Histologic features of tumors associated with a poor outcome were intravascular invasion, mitotic index > 5 in 3 microscopic hpfs, and grade III classification.

CONCLUSIONS AND CLINICAL RELEVANCE

Carboplatin administration was well tolerated and resulted in a disease-free interval and median survival time similar to those of other published protocols.

Osteosarcoma of the penile bone (os penis) in a dog

Osteosarcoma of the penile bone was diagnosed in a 5-year-old neutered male Rottweiler with recurrent dysuria. Imaging and cytological findings raised the suspicion for an osteosarcoma and ablation of the entire penis and scrotal urethrostomy was performed. The diagnosis was confirmed histologically. The dog recovered well and no postoperative signs of dysuria were observed. The dog survived without adjuvant chemotherapy for 12 months when multiple tumours in the thorax and abdomen led to it being euthanased. Penile osteosarcoma is a rare disease, but must be considered as a differential diagnosis in dogs presenting with dysuria. This is the second recorded case of a penile osteosarcoma in a dog, but the first with a detailed description of the diagnosis, treatment and outcome.

Oesophageal sarcomas in dogs: Histological and clinical evaluation

A histological grading system of oesophageal sarcomas has not been established. Thirty-two cases of oesophageal sarcomas have been reviewed for tumour characteristics and clinical outcome. Nineteen dogs underwent surgical intervention to remove oesophageal tumours; ten of them survived (median 278 days). Primary tumour types included osteosarcoma (47%), osteosarcoma with tumour giant cells (7%), fibroblastic osteosarcoma (13%), chondroblastic osteosarcoma (7%) fibrosarcoma (23%) and undifferentiated sarcoma (3%). Histological grade evaluation revealed 33% grade 1 sarcoma, 50% grade 2 and 17% grade 3. No correlation could be found between survival and signalment, duration of clinical signs, tumour type, tumour grade and chemotherapy. Chemotherapy was found to reduce lung metastases' histological scores in three cases (P=0.0007). Surgery seems to be the treatment of choice but the effect of chemotherapy warrants further investigation. Additional research of cases should be performed in order to further define prognostic factors of oesophageal sarcomas.