Oesophageal leiomyosarcoma in dogs: surgical management and clinical outcome of four cases

Retrospective immunohistochemical investigation of suspected non-visceral leiomyosarcoma in dogs

Visceral leiomyosarcoma is well described in dogs, but information about non-visceral locations and prevalence is lacking. The diagnosis of leiomyosarcoma is challenging without a gold standard, and often includes the use of immunohistochemical (IHC) stains. We used defined histopathologic patterns, histochemical staining, and IHC staining for smooth muscle actin (SMA), desmin, and laminin to characterize suspected non-visceral leiomyosarcoma in dogs at a single academic institution. In a retrospective search, we identified 24 dogs with a definitive or suspected histologic diagnosis of leiomyosarcoma in a non-visceral location. Histopathology results and clinical details were obtained. Biopsy sections were reviewed by a single pathologist using standardized histologic criteria, including light microscopic appearance, immunohistochemistry (more than two-thirds of neoplastic cells labeled with SMA and desmin or laminin), and histochemical staining (minimal-to-mild matrix deposition by Masson trichrome). Of the 24 cases of possible non-visceral leiomyosarcomas, 4 were consistent with a definitive diagnosis of non-visceral leiomyosarcoma (3) or leiomyoma (1) based on the established criteria. Only the leiomyoma had more than two-thirds of neoplastic cells label with all 3 markers; all 3 leiomyosarcomas had more than two-thirds of neoplastic cells label with SMA and laminin. Our data highlight the uncommon nature of non-visceral leiomyosarcoma and the importance of IHC for their diagnosis. A definitive diagnosis could not be made based on SMA alone, and desmin was not useful in this cohort. Further studies are needed to clarify the histopathologic, IHC, and clinical features of canine non-visceral SMA-positive mesenchymal tumors.

Endoscopic Biopsies and Histopathological Findings in Diagnosing Chronic Gastrointestinal Disorders in Dogs and Cats

Nowadays, endoscopic examination is a diagnostic tool gaining popularity in the management of gastrointestinal disorders in dogs and cats. Direct accessibility of the lumen of gastrointestinal tract combined with the mucosal biopsy provides a great diagnostic potential. Using endoscopy and endoscopically guided biopsy, one can conduct both macro- and microscopic assessment of lesions and perform many specialist adjunct examinations. Histopathological examination of mucosal biopsy specimens collected from the stomach and intestines allows us to distinguish between types of inflammations and to diagnose ulcerative, polypoid, and cancerous lesions.

Esophageal leiomyoma in a dog causing esophageal distension and treated by transcardial placement of a self-expanding, covered, nitinol esophageal stent

CASE DESCRIPTION A 10-year-old spayed female Rottweiler was referred for evaluation because of a 2-month history of regurgitation and weight loss, despite no apparent change in appetite. The dog had received antiemetic and antacid treatment, without improvement. CLINICAL FINDINGS Physical examination revealed a low body condition score (2/5), but other findings were unremarkable. Diffuse, global esophageal dilatation was noted on plain thoracic radiographs, and normal motility was confirmed through videofluoroscopic evaluation of swallowing. Transhepatic ultrasonographic and CT examination revealed a circumferential, intraparietal lesion in the distal portion of the esophagus causing distal esophageal or cardial subobstruction and no metastases. Incisional biopsy of the lesion was performed, and findings of histologic examination supported a diagnosis of esophageal leiomyoma. TREATMENT AND OUTCOME In view of numerous possible complications associated with esophageal surgery, the decision was made to palliatively treat the dog by transcardial placement of a self-expanding, covered, nitinol esophageal stent under endoscopic guidance. Two weeks after stent placement, radiography revealed complete migration of the stent into the gastric lumen. Gastrotomy was performed, and the stent was replaced and fixed in place. Twenty-four months after initial stent placement, the dog had a healthy body condition and remained free of previous clinical signs. CLINICAL RELEVANCE Diffuse benign muscular neoplasia should be considered as a differential diagnosis for acquired esophageal dilatation in adult and elderly dogs. In the dog of this report, transcardial stent placement resulted in resolution of the clinical signs, with no apparent adverse effect on digestive function. The described procedure could be beneficial for nonsurgical treatment of benign esophageal tumors in dogs.

Oesophageal angioleiomyosarcoma in a cat

A female spayed domestic longhair cat aged 3 years and 9 months was referred for investigation of regurgitation and weight loss of 2 months' duration. Thoracic radiographs revealed a soft tissue mass within the cranial mediastinum causing focal oesophageal dilation. Computed tomography confirmed a contrast-enhancing mass located cranial to the heart base, possibly originating from the oesophagus. Exploratory thoracotomy revealed an intramural soft tissue mass within the ventral oesophageal wall. Surgical excision of the mass and reconstruction of the oesophagus around an oesophageal tube was performed successfully. Histopathological examination of the mass was compatible with a spindle cell tumour with a prominent vasoformative component. Immunohistochemistry was positive for α-smooth muscle actin and von Willebrand factor protein, and negative for CD117/c-kit protein. Both histopathological and immunohistochemical findings confirmed the diagnosis of an angioleiomyosarcoma. The cat was clinically well 6 months postoperatively. To our knowledge, this is the first report of an oesophageal angioleiomyosarcoma in a cat.

Persistent Regurgitation in Four Dogs with Caudal Esophageal Neoplasia

Esophageal neoplasia is an uncommon, but important, consideration for acute and chronic regurgitation and megaesophagus in dogs. The diagnosis can be challenging, and treatment options are often limited. This case series describes four dogs with regurgitation secondary to caudal esophageal masses. All dogs presented with regurgitation, and three of the four dogs had radiographically apparent megaesophagus. In all dogs, ancillary diagnostics revealed the presence of a caudal esophageal mass resulting in esophageal obstruction, and all mass lesions were histopathologically confirmed to be neoplastic. Treatment responses were variable, with one dog still alive 37 mo postdiagnosis at the time of manuscript preparation.