Genitourinary Rhabdomyosarcoma with Systemic Metastasis in a Young Dog

Abstract

A 2-year-old intact female Golden Retriever presented due to rapidly progressing depression, ascites, dysuria, abdominal pain, and severe vaginal bleeding. At necropsy, the retroperitoneal space was expanded by multiple coalescing neoplastic nodules and the uterine wall was thickened with poorly defined neoplastic infiltrates. The urinary bladder was markedly thickened due to botryoid nodules exhibiting exophytic growth into the lumen. Metastases to lung, liver, kidney, and abdominal and thoracic lymph nodes were also noted. Microscopically, the genital tract and retroperitoneal masses were consistent with the alveolar subtype of rhabdomysarcoma, while the urinary bladder mass had characteristics of the embryonal subtype. Immunohistochemically, the neoplastic cells in all these tissue sites were intensely positive for desmin, sacromeric actin, and vimentin, while they were uniformly negative for cytokeratin and smooth muscle actin. Phosphotungstic acid hematoxylin stain revealed cross-striations in the cytoplasm of scattered neoplastic cells. Based on the gross findings, histopathology, and immunohistochemistry, genitourinary rhabdomyosarcoma with multisystemic metastases was made.

Poorly Differentiated Uterine or Cervical Sarcoma in a Young Dog

“…In the previously mentioned survey of tumors in dogs less than 1 year of age, hemanigosarcoma and osteosarcoma were the most frequently recognized sarcomas with only one case of an undifferentiated sarcoma reported [3]. Interestingly, rhabdomyosarcomas were not reported in this study; however, this tumor has primarily been described in dogs over 1 year of age [1,[5][6][7].…”

“…In young dogs, this tumor has been reported to arise in many tissues including the uterus [1,[4][5][6][7]. In the previously mentioned survey of tumors in dogs less than 1 year of age, hemanigosarcoma and osteosarcoma were the most frequently recognized sarcomas with only one case of an undifferentiated sarcoma reported [3].…”

Alveolar rhabdomyosarcoma in a dog confirmed using myogenin immunohistochemistry: a case report

“…To the authors' knowledge, in dogs, four cases of alveolar rhabdomyosarcoma (Seibold Sarnelli et al 1994;Kim et al 1996;Bae et al 2007) have been reported, which occurred in the gingiva, urinary bladder, genital tract, retroperitoneal cavity, left maxillary area and greater omentum, and these cases were confirmed via myoglobin immunohistochemistry. Myogenin is considered as the most critical marker for human rhabdomyosarcoma (Dias et al 2000).…”

“…Most rhabdomyosarcoma cases reported previously were confirmed by using an anti-myoglobin antibody (Seibold 1974;Sarnelli et al 1994;Kim et al 1996;Bae et al 2007). However, myogenin is also considered as the most critical marker for human alveolar rhabdomyosarcoma (Dias et al 2000).…”

Establishment and Characterization of Canine Rhabdomyosarcoma Cell Line CMS-C

“…It is locally invasive with moderate metastatic potential, and metastatic sites include the lungs, liver, spleen, kidneys and adrenal glands [2,13]. Based on its histopathologic features, canine RMS is classified into embryonal, botryoid, alveolar, and pleomorphic types [2,3,13]. Histological diagnosis of RMS is frequently difficult, and therefore, immunohistochemical staining may be frequently required to support the diagnosis [2,13].…”