Botryoid rhabdomyosarcoma of the urinary bladder in a filly

Current Use of Equine Laparoscopy in Urogenital Disorders: A Scoping Review of the Literature from 2000 to 2021

(1) Background: Laparoscopic surgery replaced traditional invasive techniques for the treatment of common urogenital disorders in equids. The aim of this review is to evaluate applications and the development of urogenital laparoscopy from 2001 to 2021. (2) Methods: A scoping review of literature was undertaken according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines for scoping reviews on three databases (NCBI-PubMed, Web of Science-Thompson Reuters, and SciVerse Scopus). (3) Results: A total of 452 papers were identified. After duplicate removal and title screening, 181 papers underwent abstract screening. Of these, 160 + 10 papers (cited by others) were assessed for eligibility according to the PICOs. A total of 132 papers were considered eligible. Most of the research was focused on ovaries and testes, followed by urinary bladder and general articles about laparoscopy in horses. We identified 43 original studies (33%, RCT, NoRCT, and experimental trials), 39 case series/retrospective studies (29%), 37 case reports (28%), and 13 reviews (10%, narrative or systematic). (4) Conclusions: Gonadal disorders were the most investigated. Hand-Assisted Laparoscopic Surgery (HALS) and laparoscopic-assisted surgery represent valuable options for more challenging conditions (uterine and urinary bladder disorders).

Vaginal Rhabdomyosarcoma in a Dog

A 10-year-old, female, mongrel showed hemorrhage from vulva. By magnetic resonance image (MRI) and endoscopic examination, a multipapillary mass with a grape-like appearance was found around the urethral opening. Histologically, the mass consisted of variable-sized round-, spindle-to-polygonal-shaped tumor cells including many multinuclear cells. Mitotic figures were also frequently observed. In some areas, that tumor cells were loosely arranged, with intercellular myxoid components. immunohistochemically, these tumor cells were strongly positive for vimentin and focally positive for desmin but negative for myoglobin. Thus, the case was diagnosed as a relatively poorly differentiated botryoid rhabdomyosarcoma by the macroscopic, histopathologic, and immunohistochemical identification. This is the first report of botryoid rhabdomyosarcoma developing in the vagina of a dog.

A Comparative Review of Canine and Human Rhabdomyosarcoma With Emphasis on Classification and Pathogenesis

Rhabdomyosarcomas are a diverse group of malignant mesenchymal neoplasms exhibiting variable levels of differentiation toward skeletal myocytes. Neoplastic cells may resemble relatively undifferentiated myoblasts, satellite cells, or more differentiated elongated spindle cells and multicellular myotubes. In veterinary medicine, classification into subtypes and variants is based on an outdated system derived from human pathology and is solely based on histologic characteristics. In contrast, classification of human rhabdomyosarcoma is based on histologic, immunohistochemical, and molecular diagnostic techniques, and subclassification has clinical and prognostic relevance. Relevance of tumor subtyping has not been established in veterinary medicine. Recent discoveries of components of the molecular pathogenesis and genomes of human rhabdomyosarcomas have led to new diagnostic techniques and revisions of the human classification system. The current classification system in veterinary medicine is reviewed in light of these changes. Diagnosis of rhabdomyosarcoma using histopathology, electron microscopy, and the clinical aspects of human and canine rhabdomyosarcomas is compared. The clinical features and biologic behavior of canine rhabdomyosarcomas are compared with canine soft tissue sarcomas.

Rhabdomyosarcoma in 8 Horses

This multi-institutional report describes 8 cases of rhabdomyosarcoma in horses. Four neoplasms were in the tongue and other areas of the mouth or head, 2 were in the abdominal wall, and 1 each was in right shoulder muscles and heart. Four rhabdomyosarcomas that were less than 10 cm in diameter were treated by surgical excision or radiation with no recurrence. Two neoplasms greater than 10 cm in diameter in the abdominal wall and the right shoulder were considered inoperable and led to decisions to euthanize the horses. Two neoplasms were incidental findings at necropsy. All the neoplasms were classified as embryonal except for 1 pleomorphic rhabdomyosarcoma. These 8 cases were evaluated with 9 published case reports of equine rhabdomyosarcoma. For all cases, the most common sites were limb muscles (5/17) and tongue (4/17). Metastasis was reported in 4 of the previously published cases; none was found in this study.

Poorly differentiated leiomyosarcoma of the urogenital tract in a horse

CASE DESCRIPTION

A 2-year-old Thoroughbred filly was evaluated because of hemorrhage from the vulva and suspected hematuria of 5 days' duration.

CLINICAL FINDINGS

A primary coagulopathy was ruled out on the basis of results of hematologic testing. Vaginoscopy and cystoscopy revealed a large bleeding mass in the bladder that extended into the vagina, causing marked obliteration of normal urogenital structures and difficulty in urination. Histologic examination of endoscopic and surgical biopsy specimens revealed a poorly differentiated neoplasia likely of mesenchymal origin. Chronic suppurative cystitis caused by Streptococcus zooepidemicus was also diagnosed.

TREATMENT AND OUTCOME

The tumor continued to grow despite treatment with doxorubicin and, within 45 days, was causing substantial discomfort and stranguria. Given the grave prognosis, the horse was euthanized. At necropsy, the tumor was found to have caused widespread destruction of the urinary bladder and to have invaded the broad ligament of the uterus. The mass was identified as a poorly differentiated leiomyosarcoma on the basis of results of histologic examination and immunohistochemical staining for alpha-actin.

CLINICAL RELEVANCE

Findings suggested that leiomyosarcoma should be considered in the differential diagnosis when examining horses with urogenital bleeding.

Congenital tumours and tumour-like lesions in domestic animals. 3. Horses. A review

The literature on congenital tumours and tumour-like lesions in horses was reviewed. Included were embryonic tumours and teratomas. Special attention was paid to the ubiquitous adenomatous hyperplasia of the placenta. It appears that temporal teratomas, interstitial hamartomas and placental adenomatous hyperplasia are unique in the horse. Benign teratoma of the undescended testis is far more frequent in the horse than in other species. In horses, as in calves and pigs, congenital skin tumours were of papillomatous, vascular and melanocytic types. The sporadic occurrence of congenital tumours in the horse did not provide an etiologic or pathogenetic clue. The possibility of oncogenic viruses in cases of congenital skin papilloma or malignant lymphoma could neither be proven, nor be excluded. Hereditary tumours were not encountered.

Transitional cell carcinoma of the urinary bladder in a Thoroughbred, with intra-abdominal dissemination

A 14-year-old Thoroughbred gelding with a history of acute onset of hematuria was presented for necropsy. Transitional cell carcinoma of the urinary bladder with intra-abdominal dissemination was diagnosed. Tumor masses were observed on the splenic capsule and surrounding the distal abdominal aorta. Tumor cells showed diffuse cytoplasmic reactivity for cytokeratin but were negative for epithelial membrane antigen, carcinoembryonic antigen, tumor-associated glycoprotein 72, and vimentin.