Liposarcomas in dogs: 56 cases (1989–2000)

Surgical management of urethral obstruction secondary to perineal liposarcoma in a dog: a case report

BACKGROUND

Swelling of the perineal region in male dogs is most commonly caused by a perineal hernia. Clinical signs associated with perineal hernia are constipation, tenesmus or stranguria. This case report documents a rare cause of perineal swelling created by the growth of a malignant tumour leading to urethral obstruction and subsequent stranguria.

CASE PRESENTATION

An 11-year-old neutered male German Shepherd was presented for swelling in the perineal region and stranguria for three days. Complete blood count and serum biochemistry were unremarkable. Ultrasound revealed a heterogeneous mass in the perineal region. Retrograde urethrography showed a severe narrowing of the urethra caudal to the pelvis. A fine-needle aspirate of the mass was highly suspicious for liposarcoma. Staging was performed by computed tomography (CT) of the thorax and abdomen. Total penile amputation in combination with pubic-ischial pelvic osteotomy, transposition of the remaining urethra through the inguinal canal, V-Y-plasty cranial to the prepuce and preputial urethrostomy were performed to remove the tumour. Histopathology confirmed a well-differentiated liposarcoma with complete histological margins. Six months after the surgery the dog was doing well and there were no signs indicating local tumour recurrence.

CONCLUSIONS

Wide surgical excision is generally recommended for soft tissue sarcomas, however this is sometimes not feasible for large tumours. In the case reported here, tumour resection was achieved by a combination of several surgical techniques with a good clinical outcome.

Computed tomographic features of an axillary liposarcoma with hepatic metastasis

A geriatric dog presented for lethargy, dyspnea, and urinary incontinence. Thoracic radiographs demonstrated a large, mixed fat, and soft tissue opaque axillary mass and a pulmonary mass. Computed tomography (CT) further characterized these masses and revealed innumerable fat-attenuating hepatic masses and cranial mediastinal lymphadenopathy. Histopathology of the axillary and hepatic masses confirmed grade two primary axillary liposarcoma with hepatic metastasis. Cytology of the pulmonary mass was consistent with a pulmonary carcinoma. This is the first published CT description of fat-attenuating metastatic hepatic liposarcoma in a dog.

Prevalence of pulmonary nodules suggestive of metastasis at presentation in dogs with cutaneous or subcutaneous soft tissue sarcoma

OBJECTIVE

To investigate the prevalence of pulmonary nodules suggestive of metastasis at the time of initial presentation in dogs with cutaneous or subcutaneous soft tissue sarcomas (STSs) and no previous related thoracic diagnostic imaging.

ANIMALS

146 client-owned dogs with a cutaneous or subcutaneous STS.

PROCEDURES

Medical records were retrospectively searched to identify dogs with STSs that underwent initial thoracic diagnostic imaging when presented for referral examination between September 2014 and March 2018. Data collected included patient and tumor characteristics. Results were evaluated for dogs grouped on the basis of variables of interest (eg, STS grade, duration, or history).

RESULTS

Initial thoracic imaging was performed with CT (131/146 [89.7%]) or radiography (15 [10.3%]). Although the presence or absence of pulmonary nodules suggestive of metastasis on thoracic imaging was uncertain in 9 dogs, it was certain in the remaining 137 dogs, with nodules present in 16 (11.7%) dogs (5/77 [6%] with grade 1 STSs, 2/36 [6%] with grade 2 STSs, and 9/24 [38%] with grade 3 STSs). The odds of such pulmonary nodules being present on initial examination were higher (OR, 10.8 and 3.14, respectively) for dogs with grade 3 STSs (vs grade 1 or 2 STSs) and for dogs with an STS duration > 3 months (versus ≤ 3 months).

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that pulmonary staging was a low-yield diagnostic procedure for dogs with grade 1 or 2 cutaneous or subcutaneous STSs, especially when tumors had been present for ≤ 3 months.

p53 Expression in Canine Liposarcoma Correlates With Myxoid Variant and Higher Proliferative Activity

Canine liposarcoma is classified as well differentiated (WDL), dedifferentiated (DDL), myxoid (ML), and pleomorphic (PL). Overexpression of the protooncogene MDM2 has been reported in WDL and DDL, but little is known regarding the role of p53 in their tumorigenesis. The aim of this study was to assess p53 expression in canine liposarcoma and compare it with subtype, grade, mitotic count (MC), Ki67 labeling index (LI), and MDM2 expression. Forty-seven cases were included (13 WDL, 3 DDL, 7 ML, and 24 PL); 17 were MDM2-positive (13 WDL, 3DDL, and 1ML). Five were p53-positive (4 ML and 1 WDL) but DDL and PL were consistently negative. p53 expression correlated with higher Ki67-LI, higher MC, and myxoid histotype. No correlation was found with grade and MDM2 expression. Based on these results canine liposarcoma seems to embody a group of neoplasms whose subtypes, especially ML, may represent distinct diseases rather than morphological variants of the same entity.

Computed tomographic findings, surgical management and postoperative outcomes of large intermuscular lipomas in the hindlimb of 11 dogs

OBJECTIVE

Lipomas are benign adipose tissue tumours of mesenchymal origin and can originate in various locations. Intermuscular lipomas in the thigh can cause substantial hindlimb expansion in the dog. We describe the computed tomography findings, surgical management and the outcomes of 11 dogs with large intermuscular lipomas of the hindlimb.

DESIGN

Retrospective case series.

METHODS

Medical records between 2009 and 2019 of dogs presenting to The Animal Hospital at Murdoch University were reviewed. Inclusion criteria included dogs with a histologically confirmed, large hindlimb lipoma that was surgically excised following preoperative computed tomography (CT) imaging.

RESULTS

CT with intravenous contrast revealed a well-defined, smoothly marginated, fat attenuating mass with minimal vascularity, separating the muscle bellies of the caudal hindlimb. The mass was often in close proximity to the femoral artery and vein. All lipomas were marginally excised. At surgery, some lipomas were intimately associated with the sciatic nerve and some showed infiltration of, or attachment to, neighbouring muscle that could be excised en bloc with the lipoma. Postoperative closed-suction wound drainage was used in 6 of 11 dogs. One dog required revision surgery due to partial wound dehiscence. Long-term follow-up with owners reported good postoperative function of the affected hindlimb in all dogs. One dog developed an infiltrative lipoma in the same location 22 months post-excision.

CONCLUSION

Preoperative CT allowed a presumptive diagnosis of intermuscular lipoma and facilitated surgical planning for marginal excision. Large intermuscular lipomas of the hindlimb can be safely excised with minimal short-term complications, good long-term functional outcome and low likelihood of recurrence.

Primary Myxoid Liposarcoma of the Greater Omentum in a Rhesus Macaque (Macaca mulatta)

We here report a spontaneous case of primary myxoid liposarcoma of the greater omentum with subsequent transperitoneal recurrence. The primary mass was incidentally found during an exploratory laparotomy for a presumed diagnosis of trichobezoar or phytobezoar and was removed surgically. Histopathologic examination of the mass revealed the presence of a myxoid liposarcoma. Eleven months later, recurrence with severe transperitoneal sarcomatosis of the myxoid liposarcoma was noted and confirmed by necropsy and histopathology. A review of the literature revealed that liposarcoma in NHP conforms to the behavior and prognosis of this neoplasm in humans.

Canine sarcomas as a surrogate for the human disease

Pet dogs are becoming increasingly recognized as a population with the potential to inform medical research through their treatment for a variety of maladies by veterinary health professionals. This is the basis of the One Health initiative, supporting the idea of collaboration between human and animal health researchers and clinicians to study spontaneous disease processes and treatment in animals to inform human health. Cancer is a major health burden in pet dogs, accounting for approximately 30% of deaths across breeds. As such, pet dogs with cancer are becoming increasingly recognized as a resource for studying the pharmacology and therapeutic potential of anticancer drugs and therapies under development. This was recently highlighted by a National Academy of Medicine Workshop on Comparative Oncology that took place in mid-2015 (http://www.nap.edu/21830). One component of cancer burden in dogs is their significantly higher incidence of sarcomas as compared to humans. This increased incidence led to canine osteosarcoma being an important component in the development of surgical approaches for osteosarcoma in children. Included in this review of sarcomas in dogs is a description of the incidence, pathology, molecular characteristics and previous translational therapeutic studies associated with these tumors. An understanding of the patho-physiological and molecular characteristics of these naturally occurring canine sarcomas holds great promise for effective incorporation into drug development schemas, for evaluation of target modulation or other pharmacodynamic measures associated with therapeutic response. These data could serve to supplement other preclinical data and bolster clinical investigations in tumor types for which there is a paucity of human patients for clinical trials.

Use of endoscopic-guided electrocautery ablation for treatment of tracheal liposarcoma in a dog

CASE DESCRIPTION A 7-year-old 44-kg (97-lb) neutered male Great Pyrenees was referred for evaluation because of episodic dyspnea with cyanosis of 1 to 2 weeks' duration. Three days prior to evaluation, the clinical signs had worsened, including 1 episode of collapse. CLINICAL FINDINGS Thoracic radiography and CT revealed a well-delineated soft tissue mass, located approximately 1.5 cm cranial to the carina and occupying almost 90% of the tracheal lumen. A CBC and serum biochemical analysis were performed, and all results were within reference limits. TREATMENT AND OUTCOME Tracheoscopy confirmed the presence of a broad-based bilobate mass that was protruding from the right dorsal aspect of the trachea and occupied almost the entire tracheal lumen. The mass was successfully resected by endoscopic-guided electrocautery ablation. Findings of histologic evaluation were consistent with a diagnosis of liposarcoma. Immediately following the ablation procedure, the previously noted clinical signs of respiratory tract disease resolved. On follow-up examination 12 months later, no regrowth of the mass was evident on thoracic helical CT and tracheoscopy. CLINICAL RELEVANCE Endoscopic-guided electrocautery ablation of tracheal liposarcoma was a safe and effective minimally invasive treatment for the dog of this report. The procedure was brief and appeared to be well tolerated, resulting in immediate improvement of clinical signs.

Liposarcoma of the spermatic cord in a Toy Poodle

Liposarcoma of the spermatic cord is extremely rare in dogs and humans. This report describes the clinical signs, typical diagnostic imaging including ultrasound and computed tomography, and treatment of a liposarcoma of the spermatic cord of a Toy Poodle confirmed by histological examination after a surgical procedure. This case highlights the importance of preoperative diagnostic imaging and histopathological examination in dogs with an inguinal or scrotal mass.

Immunoreactivity of Canine Liposarcoma to Muscle and Brown Adipose Antigens

Liposarcoma, rhabdomyosarcoma, and hibernoma share some overlapping histologic and immunohistochemical features. Although immunohistochemistry (IHC) is commonly used in the diagnosis of these neoplasms, expression of muscle markers has been reported in human liposarcoma and canine hibernoma in addition to rhabdomyosarcoma. Thus, these neoplasms are a diagnostic challenge but important to distinguish because of differences in prognosis and treatment. Rhabdomyosarcoma and liposarcoma are both malignant, but rhabdomyosarcoma has a higher potential for metastasis. In contrast, hibernomas are benign with low risk of recurrence. This study investigated expression of the muscle markers desmin, myogenin, and α-smooth muscle actin (α-SMA) and the brown fat marker uncoupling protein 1 (UCP1) in 25 cases of canine liposarcoma using IHC. Oil red O histochemistry was performed to confirm the presence of lipid and the diagnosis of liposarcoma in cases that were not well-differentiated. The 25 cases included 15 well-differentiated, 5 pleomorphic, 3 myxoid, and 2 dedifferentiated subtypes of liposarcoma. By IHC, 23 of 25 expressed UCP1, 7 of 25 expressed α-SMA, 7 of 25 expressed desmin, and 3 of 25 expressed myogenin with no clear relationship of antigen expression and tumor subtype. These findings clarify the immunohistochemical profile of canine liposarcoma and suggest overlap in the expression of several muscle antigens and UCP1 between liposarcoma, hibernoma, and rhabdomyosarcoma.

Well-differentiated inflammatory liposarcoma with metastasis in a 6-y-old cat

Liposarcomas are rare malignant tumors showing adipocytic differentiation. We report a well-differentiated liposarcoma in a 6-y-old, male neutered cat with a prominent inflammatory component and metastatic spread to the lungs. The patient was initially presented because of fever, lethargy, and a firm subcutaneous inguinal mass. A Tru-cut biopsy of the mass revealed a mixture of well-differentiated adipocytes and lymphoplasmacytic-histiocytic inflammation, interpreted as panniculitis. The mass was surgically excised but recurred 4 mo later. A second excisional biopsy yielded similar histologic findings. A third recurrence of the mass was associated with lung nodules. Histopathology of the recurring and metastatic masses confirmed the diagnosis of well-differentiated inflammatory liposarcoma with pulmonary metastases. The neoplasm had an intense inflammatory component, which obscured the underlying features of liposarcoma and made differentiation from steatitis difficult. This inflammatory variant of a well-differentiated liposarcoma should be considered as a differential in tumorous steatitis-like lesions.

Well-differentiated liposarcoma with chondroid metaplasia in the auricle of a dog

A 13-year-old spayed female dog had a mass in the left auricle. Grossly, connection between the mass and original auricular cartilage was not recognized. The mass was unencapsulated and contained multiple islands of mature hyaline cartilage and neoplastic adipocytes. The neoplastic cells comprised predominant mature adipocytes, scattered lipoblasts and irregular round to spindle cells with moderate atypia. The atypical cells occasionally had lipid droplets. A diagnosis of well-differentiated liposarcoma (WDL) with chondroid metaplasia was made. This is the first report for liposarcoma with chondroid metaplasia in the auricle of domestic animals.

Co-occurrence of a metastatic mammary liposarcoma and an ovarian sex-cord stromal tumor in a dog

Sarcoma arising in the mammary gland is a rare tumor in dogs, and primary liposarcoma with metastatic behavior has never been previously reported among canine mammary tumors. A 14-year old female poodle had a mammary mass diagnosed as pleomorphic liposarcoma. Two years following surgical removal, the tumor recurred in the mammary gland with lymph node metastases. In addition, a sex-cord stromal tumor was identified in the ovary. Immunohistochemistry was performed on both tumors that were positive for oestrogen and progesterone receptors. Moreover, the ovarian tumor was positive for calretinin. This is the first report to the authors' knowledge, of the co-occurrence of a pleomorphic liposarcoma of the mammary gland and an ovarian sex-cord stromal (gonadostromal) tumor in the dog.

Splenic liposarcoma in dogs: 13 cases (2002-2012)

OBJECTIVE

To describe the clinical signs, diagnostic findings, surgical management, and outcome in dogs with splenic liposarcoma.

DESIGN

Retrospective case series.

ANIMALS

13 client-owned dogs with splenic liposarcoma.

PROCEDURES

Medical and pathology records of dogs with a histopathologic diagnosis of splenic liposarcoma from 2002 to 2012 were reviewed for the following data: clinical signs, CBC, biochemical profile, thoracic and abdominal imaging, surgical management, histologic grade, and outcome (local recurrence, distant metastasis, and survival time). Telephone interviews were conducted with referring veterinarians.

RESULTS

The median survival time (MST) was 623 days (range, 1 to 1,283 days). In 5 dogs that died of splenic liposarcoma, survival times ranged from 42 to 369 days. Metastasis at the time of surgery was a negative prognostic indicator: the MST was 45 days for dogs with metastasis and 767 days for dogs without metastasis. Dogs with grade 1 splenic liposarcoma had a significantly greater MST (1,009 days), compared with dogs with grade 2 or 3 splenic liposarcoma (MST, 206 and 74 days, respectively).

CONCLUSIONS AND CLINICAL RELEVANCE

Results confirmed that splenic liposarcoma is a rare differential diagnosis in dogs with a splenic mass. Survival time was influenced by preoperative clinical stage and histologic grade.

Tyrosine Kinase Receptor Expression in Canine Liposarcoma

The expression of tyrosine kinase receptors is attracting major interest in human and veterinary oncological pathology because of their role as targets for adjuvant therapies. Little is known about tyrosine kinase receptor (TKR) expression in canine liposarcoma (LP), a soft tissue sarcoma. The aim of this study was to evaluate the immunohistochemical expression of the TKRs fibroblast growth factor receptor 1 (FGFR1) and platelet-derived growth factor receptor–β (PDGFRβ); their ligands, fibroblast growth factor 2 (FGF2) and platelet-derived growth factor B (PDGFB); and c-kit in canine LP. Immunohistochemical labeling was categorized as high or low expression and compared with the mitotic count and MIB-1–based proliferation index. Fifty canine LPs were examined, classified, and graded. Fourteen cases were classified as well differentiated, 7 as myxoid, 25 as pleomorphic, and 4 as dedifferentiated. Seventeen cases were grade 1, 26 were grade 2, and 7 were grade 3. A high expression of FGF2, FGFR1, PDGFB, and PDGFRβ was identified in 62% (31/50), 68% (34/50), 81.6% (40/49), and 70.8% (34/48) of the cases, respectively. c-kit was expressed in 12.5% (6/48) of the cases. Mitotic count negatively correlated with FGF2 ( R = –0.41; P < .01), being lower in cases with high FGF2 expression, and positively correlated with PDGFRβ ( R = 0.33; P < .01), being higher in cases with high PDGFRβ expression. No other statistically significant correlations were identified. These results suggest that the PDGFRβ-mediated pathway may have a role in the progression of canine LP and may thus represent a promising target for adjuvant cancer therapies.

High-Grade Myxoid Liposarcoma (Round Cell Variant) in a Dog

A 10-year-old, neutered male, Basset hound had a 26 × 21 × 21 cm infiltrative mass on the left abdominal wall that did not extend into the peritoneal cavity based on radiographs and abdominal computed tomography. Cytological examination revealed moderate numbers of neoplastic round cells, which frequently contained numerous round, clear, cytoplasmic vacuoles. Histologically, the tumour was composed of two morphologically distinct cell populations forming a continuum of heterogeneously differentiated cells. The primary spindle-shaped population formed streams with abundant, lightly eosinophilic, alcian blue-positive, myxoid matrix. The second population was arranged in sheets and had a round cell appearance. Scattered within both populations were neoplastic cells containing variably sized, intracytoplasmic, osmium tetroxide-positive vacuoles (lipid). Multifocal large pools of mucin formed pseudocysts, and numerous small capillaries were present throughout the neoplasm. According to the current World Health Organization veterinary classification of liposarcomas, this neoplasm had morphological features of both the myxoid and pleomorphic variants of liposarcoma; however, it was analogous to the recently defined high-grade myxoid liposarcoma in man. Myxoid liposarcoma with round cells has not been described previously in dogs. This case highlights the need to potentially re-evaluate the current classification of liposarcomas in animals.

CASE REPORT: ENDOMETRIAL STROMAL SARCOMA AND LIPOSARCOMA IN AN AFRICAN HEDGEHOG (Atelerix albiventris)

A 2-year-7-month-old female intact African hedgehog was presented with a subcutaneous mass around the right side of the neck as well as an intra-abdominal mass found during palpation. Surgical excision and exploratory laparotomy were performed. A uterine mass was identified during laparotomy and ovariohysterectomy was performed. The botryoid mass measured [Formula: see text][Formula: see text]cm and was located in the right uterine horn. It had a meat-like texture and was yellow-white and dark red in color. The removed subcutaneous mass measured [Formula: see text][Formula: see text]cm. The mass was well-encapsulated and had a yellow-white homogeneous texture on the cut surface. Histologically, the myometrium was invaded by neoplastic cells and the tissue boundaries were not obvious. Neoplastic cells were arranged in a whirling or intersecting pattern, with strong angiogenesis present. Vacuolated nuclei were round and oval to cigar shaped, with one to multiple nucleoli present. Immunohistochemistry revealed a positive reaction for CD10, but a negative reaction for smooth muscle actin (SMA) and desmin in the uterine neoplastic cells. Histologically, well-differentiated adipocytes with sheets of undifferentiated polygonal neoplastic cells, which were characterized by vacuolated nuclei with prominent multiple nucleoli, were found in the subcutaneous mass. Neoplastic cells of the subcutaneous mass were positively stained with antibodies of MDM2 and estrogen receptor (ER), but failed to give a positive result for vimentin because the cross-species interaction was insufficient. The definitive diagnosis was endometrial stromal sarcoma and liposarcoma in an African hedgehog.

Round Cell Variant of Myxoid Liposarcoma in a Japanese Macaque (Macaca fuscata)

A 5-year-old, female, Japanese Macaque ( Macaca fuscata) was diagnosed with round cell variant of myxoid liposarcoma. At necropsy, multifocal to coalescing, reddish tan to white nodules, ranging from 0.5 to 1 cm in diameter, were noted throughout the omentum and retroperitoneum. Similar neoplastic nodules were also present in diaphragm, abdominal wall, and on hepatic capsule. Microscopically, neoplastic masses consisted of round to polyhedral cells, which had round, often eccentric nuclei and abundant eosinophilic granular and microvacuolated cytoplasm; Oil red O staining demonstrated large numbers of lipid droplets in the cytoplasm. Ultrastructurally, the cytoplasm of the tumor cells was packed with occasional lipid vacuoles and numerous enlarged mitochondria. Immunohistochemistry revealed tumor cells were positive for vimentin, while negative to cytokeratin, actin, and Factor VIII-related antigen. To the authors' knowledge, this is the first report of round-cell variant of myxoid liposarcoma in nonhuman primate.

Metastatic Liposarcoma in a South African Fur Seal (Arctocephalus pusillus)

A 14-year-old female South African fur seal (Arctocephalus pusillus) was presented with a large skin mass on the right shoulder. At necropsy examination, multiple white nodules were found in the lungs, liver, spleen and right axillary lymph nodes. Histologically, the skin mass was composed of round to polygonal neoplastic cells with round to oval nuclei and variably sized cytoplasmic vacuoles. Cellular and nuclear atypia were prominent. Immunohistochemically, the neoplastic cells expressed vimentin, but not cytokeratins, S100 protein, adipophilin or desmin. The cytoplasmic lipid droplets stained positively with oil red O. Metastasis was seen in the lungs, liver, spleen and right axillary lymph nodes, with similar morphological features to the skin mass. Based on these findings, a diagnosis of a pleomorphic liposarcoma with systemic metastasis was made. No previous reports of metastatic liposarcomas have been published in marine mammals.

Histological Classification and Immunohistochemical Evaluation of MDM2 and CDK4 Expression in Canine Liposarcoma

Canine liposarcoma is an uncommon soft tissue sarcoma usually arising in the subcutis. While liposarcoma classification in dogs is based solely on histology, in humans it depends on the detection of genetic abnormalities that can lead to specific protein overexpression. This study is an immunohistochemical evaluation of MDM2 and CDK4 expression in canine liposarcoma designed to assess the correlation of these proteins with histologic type, grade, mitotic index and Ki67 labeling index and evaluate their utility in improving tumor classification. Fifty-three liposarcomas were retrospectively collected: 24 were well differentiated liposarcomas (WDL), 16 of which expressed MDM2 and 21 CDK4; 7 were myxoid liposarcomas (ML), 1 of which expressed MDM2 and 5 expressed CDK4; 18 were pleomorphic liposarcomas (PL), all were MDM2 negative and 12 expressed CDK4. Four tumors were morphologically consistent with dedifferentiated liposarcoma (DDL) a subtype described only in humans: 3 expressed MDM2 and 4 expressed CDK4. MDM2 expression correlated with histotype (highly expressed in WDL and DDL) and grade (highly expressed in grade 1 tumors). Histotype correlated with the Ki67 labeling index (lowest in WDL and highest in DDL). A revised classification, considering MDM2 expression, allowed 8 WDL to be reclassified as PL and correlated significantly with mitotic and Ki67 labeling index (both significantly lower in WDL and progressively higher in ML and DDL). These results partially parallel data reported for human liposarcomas, suggesting that WDL and DDL are distinct neoplastic entities characterized by MDM2 expression, which may represent a useful diagnostic and potentially prognostic marker for canine liposarcoma.

Liposarcoma or invasive lipomatosis in flower horn fish, hybrid cichlid: clinical, radiological, ultrasonographical and histopathological study

Liposarcoma or invasive lipomatosis affecting three indoor aquarium fish (flower horn fish, hybrid cichlid) is characterized, by the presence of mature adipocytes of variable sizes and by an invasive behaviour, which affected internal organs and eyes of all cases. Detailed macroscopic, radiological, ultrasonographical and histopathological features are presented. All fish had bilateral exophthalmia with some masses around the eyes. Ultrasonography confirmed the presence of hyperechoic masses in the eyes. Histopathology of all cases described the presence of variable-sized adipose cells in the eyes. The suggested diagnosis is well-differentiated liposarcoma or invasive lipomatosis. This is the first report of liposarcoma or invasive lipomatosis in flower horn fish, hybrid cichlid.

The co-existence of a myxoid liposarcoma and leiomyoma in the same ovarian mass of a dog

A 15-year-old, female mixed-breed dog presented with abdominal distention. An exploratory laparotomy revealed a large left ovarian mass (20 × 15 × 12 cm). Histopathological examination of the mass revealed a mixed myxoid liposarcoma and a well-differentiated leiomyoma. Four months after surgical removal of the mass, the dog died due to multiorgan metastasis. The metastasis was composed solely of the liposarcoma component. The liposarcoma component was Alcian Blue- and Oil red O-positive, and demonstrated immunoreactivity with S-100, adipophilin and vimentin. Electron microscopy revealed that the tumor cell cytoplasms were packed with lipid vacuoles and dilated rough endoplasmic reticulum. To our knowledge, this is the first report of myxoid liposarcoma and leiomyoma co-existing in a canine ovary.

Pathological characterization of primary splenic myxoid liposarcomas in three dogs

Non-angiomatous-non-lymphomatous sarcomas (NANLs) represent 23%-34% of canine primary splenic sarcomas. Splenic liposarcomas account for 2%-6% of NANLs but myxoid variants are rarely reported and information on their behaviour is fragmentary. An 8-year-old male crossbreed (case 1), a 12-year-old female French bulldog (case 2), and an 11-year-old crossbreed (case 3) underwent splenectomy after the detection of a splenic nodule. Histology, histochemistry, immunohistochemistry, and transmission electron microscopy (TEM) were performed. Bundles of spindle-to-polygonal cells containing occasional cytoplasmic oil-red-O positive vacuoles embedded in an Alcian blue-positive extracellular matrix were observed. Aggregates of round cells were detected in cases 1 and 3. All tumours were vimentin positive and actin, desmin, Factor VIII, and S100 negative. The TEM evidenced different maturational stages of adipose cells (lipoblasts, intermediate, and undifferentiated). All the cases developed hepatic metastases and were euthanized. Disease free interval was 2 months in cases 1 and 3, and 21 months in case 2. The presence of a neoplastic embolus in case 1 and areas of round cell differentiation in cases 1 and 3 represented the sole prognostic indices.

Liposarcoma in animals: literature review and case report in a domestic pig (Sus scrofa)

Liposarcomas are malignant tumors of adipocytes. The current report describes a liposarcoma in a 2.5-year-old, mixed-breed commercial sow that was detected during meat inspection. On gross examination, a firm, whitish, multinodular, 20 cm ×10 cm mass was observed in the perirenal area along with smaller nodules multifocally scattered within the renal parenchyma. Histological examination revealed an anaplastic sarcoma with clear intracytoplasmic lipidic vacuoles that were positive for Sudan black staining. Most of the cells were also positive for S100 and vimentin immunohistochemistry. Based on these results, a diagnosis of a perirenal liposarcoma was established. To the authors' knowledge, no previous reports of liposarcomas in pigs have been published. This report also includes a review of the literature published on animal liposarcomas.

Canine Perivascular Wall Tumors

Canine perivascular wall tumors (cPWTs) arise from vascular mural cells and are included among soft tissue sarcomas (STSs). Most prognostic studies are performed on canine STSs as a general group and regardless of their specific histotype. The aim of this study was to identify pathological parameters and profiles with prognostic impact for cutaneous/subcutaneous cPWTs. Anatomical location, type of growth, surgical margins, and size and depth of the tumor were collected in 56 cPWTs. The association between each pair of variables was evaluated by χ2 test. Multiple correspondence analysis (MCA) was performed to describe the multivariate association of variables and was followed by cluster analysis to identify specific pathological profiles. The prognostic impact of variables and profiles was assessed by Cox regression model. Size and depth were significantly associated with increased relapse probability. Cases with complete surgical margins did not recur. Other single variables were not significantly associated with relapse. Cluster analysis on MCA considering site, depth, margins, and type of growth identified 3 pathological profiles associated with PWT relapse and having a high prognostic impact. Major prognostic factors for cPWTs were tumor size, depth of growth, and pathological profiles.

Anatomic distribution and clinical findings of intermuscular lipomas in 17 dogs (2005-2010)

Intermuscular lipomas (IML) in dogs can be associated with ominous clinical signs, especially in the thoracic limb. However, the prognosis is excellent following surgical excision. There is a paucity of information in the veterinary literature regarding IML. Our objective was to describe the anatomical location, imaging techniques, and clinical findings in a series of dogs that were diagnosed and treated for IML. The prevalence of thoracic versus pelvic limb IML was not different. Most IML of the thoracic limb were located in the axilla. Operative time for IML of the thoracic and pelvic limb averaged 60 minutes. Complications were rare after marginal surgical excision and recurrence was not seen in any of the cases in this report. Intermuscular lipomas of the axilla are as common as IML of the caudal thigh. Surgical treatment of both axillary and caudal-thigh IML is associated with an excellent prognosis in dogs.

Intraosseous lipoma in the ulna and radius of a two-year-old Leonberger

This report describes a case of intraosseous lipoma in a two-year-old Leonberger. The dog was presented with a history of ten month lameness in the right forelimb. A massive swelling from the elbow to the carpus of the right forelimb was visible. Treatment with anti-inflammatory medications by the local veterinarian for ten months was unsuccessful and the dog was presented at the university clinic. Radiographic images showed that the diaphyseal part of the ulna was affected by extensive cyst-like osteolysis. Furthermore, the distal metaphysis of the radius showed cyst-like osteolytic changes. The soft-tissue mass and parts of the ulna periosteum were surgically resected. Histopathological analysis of the mass in combination with clinical, surgical and radiographic findings was diagnostic for an intraosseous lipoma. The dog had a good long-term outcome as it was free of any signs of recurrence at the follow-up examinations performed after 18 months and after five years. To the authors' knowledge, this is the first description of intraosseous lipoma in a dog.

Liposuction for removal of lipomas in 20 dogs

OBJECTIVES

To review the success rates for liposuction of lipomas in dogs, report early complications and medium-term outcomes and formulate recommendations on the most appropriate candidates for liposuction.

METHODS

Retrospective study of 20 dogs with 76 lipomas diagnosed by cytology, in which dry liposuction was attempted. Case records were reviewed for number and size of the lipomas, efficacy of liposuction, frequency and types of complication and likelihood of recurrence.

RESULTS

Liposuction was successful in removing 73 of 76 lipomas (96%). Simple, encapsulated lipomas less than 15 cm in diameter were most easily removed, with minimal risk of complication. Giant lipomas contained fibrous trabeculae that hindered liposuction and resulted in poor fat retrieval. Giant lipomas were also associated with a high risk of bruising, haematoma and seroma, especially when inguinal in location. Regrowth was noted at follow-up between 9 and 36 months in 28% of lipomas.

CLINICAL SIGNIFICANCE

Liposuction may be less invasive and more attractive to owners than conventional surgery for lipomas up to 15 cm in diameter. Liposuction is not recommended for infiltrative or giant inguinal lipomas. Regrowth can be expected in a high proportion of lipomas, which should be considered when choosing liposuction over conventional excision.

Pericardial lipoma in a geriatric dog with an incidentally discovered thoracic mass

An intrathoracic mass was discovered as an incidental finding in a 14-year-old, spayed, female Rottweiler cross during evaluation of urinary incontinence. Computed tomography suggested a pericardial or pleural location and high adipose content of the mass. The mass was removed via lateral thoracotomy with partial pericardectomy and was diagnosed as a pericardial lipoma. The dog recovered well, and there was no evidence of recurrence approximately one year later. Adipose tumours of the heart and its associated structures are rare in dogs and have been associated with both successful and fatal outcomes.

Liposarcoma in the nasal cavity of a cow

Liposarcomas are rare neoplasms in domestic animals, but have been reported to occur in many species. In humans, liposarcoma is one of the most common malignant mesenchymal tumors. Classification of liposarcomas in humans has been well established and categorization by type can be of prognostic value; no such unique classification scheme has been established for liposarcomas in animals. Liposarcoma of the head and neck in humans are uncommon, and are rarely reported in the nasal cavity, sinuses, and nasopharynx. To our knowledge, a liposarcoma has never been reported in the nasal cavity of a domestic animal. In this report we describe a liposarcoma that developed in the nasal cavity of a cow, with local invasion into the oral cavity.

Combined Use of Surgery and Radiation in the Treatment of an Intradural Myxoid Liposarcoma in a Dog

An intradural-extramedullary myxoid liposarcoma of the high cervical spine was diagnosed in a 9-year-old, spayed female Cavalier King Charles spaniel that was presented for a 2-month history of cervical pain and tetraparesis. Radiation therapy applied after surgery resulted in complete remission of the neurological deficits. The tumor recurred 18 months after surgical excision. A second surgery and another course of radiotherapy again resulted in complete remission of the clinical signs. The dog was euthanized 11 months after the second surgery because of tumor recurrence.