Misdiagnosis of primary pleomorphic rhabdomyosarcoma of the right thigh in a young adult: A case report

Abstract

Abstract. Pleomorphic rhabdomyosarcoma (PRMS) is a rare type of soft tissue tumor accounting for <2% of all adult sarcomas. The present study describes a case of a 28-year-old male patient with primary PRMS of the right thigh. The patient was initially diagnosed with a schwannoma and underwent conservative therapy at a local hospital. At the 6-month follow-up, the patient reported a marked increase in the size of the mass. Finally, the patient underwent fine-needle aspiration and total tumor resection. The tumor measured 11x9x5 cm³ in size and was located in the vastus intermedius muscle. According to histological and immunohistochemical findings, a diagnosis of PRMS was confirmed by an expert pathology consultant. Postoperative follow-up at 3 months revealed no evidence of recurrent disease or residual side effects from therapy. However, it is imperative that such cases are closely monitored following surgery, in order to evaluate the long-term efficacy of the procedure, since misdiagnosis may increase the risk of recurrence and metastasis. The present case is noteworthy due to the misdiagnosis of PRMS, the large size of the mass and the young age of the patient. IntroductionRhabdomyosarcoma (RMS) is a highly malignant type of soft tissue tumor with skeletal muscle differentiation. The incidence of RMS is ~43 cases per 10 million each year for individuals under the age of 20 (1). In patients with localized disease, the relapse-free survival rate has improved to 70-80% (2). However, the prognosis for patients with metastases is relatively poor, with a 5-year survival rate of only 30% (3). Diagnostic methods for RMS include clinical and laboratory examination, imaging analysis, pathological diagnosis and immunohistological examination (4). RMS has been divided into 3 main subtypes: Embryonal, alveolar and pleomorphic RMS (PRMS). The most common subtypes are the embryonal and alveolar subtypes (5). Primary PRMS is relatively rare and primarily affects adults, with a peak incidence in the fifth decade of life (6-9). It most commonly arises in the deep soft tissues of the extremities. Due to the similarities in clinical manifestations and imaging features between PRMS and other soft tissue tumors, PRMS is often misdiagnosed (10). The present study presents a case of PRMS that was misdiagnosed as schwannoma. This misdiagnosis resulted in the progression of the mass, and only following fine-needle aspiration and histological and immunohistochemical analysis was the tumor origin confirmed to be the skeletal muscle, and a final diagnosis of PRMS of the right thigh was provided. The present study was approved by the Ethics Review Committee of The First Affiliated Hospital of Nanchang University (Nanchang, China), and written informed consent was obtained from the patient. Case reportIn August 2014, a 28-year-old male patient presented to the Orthopedic Clinic of Taihe County People's Hospital (Ji'an, China) with a chief complaint of swelling in his right thigh for 1 month. According to the local district general hospital...

Primary alveolar rhabdomyosarcoma of retrorectal-presacral space in an adult patient

“…[ 6 ] The tumors may appear isointense and low signal intensity to surrounding skeletal muscle on T1-weighted MRI, high and heterogeneous signal on T2-weighted images and contrast-enhanced to variable degrees on T1-weighted sequences. [ 15 , 16 ] Alveolar subtypes, in particular, may show areas of hemorrhage and necrosis as well. [ 17 ] But, in the case presented here, CT of the abdomen showed a sharply defined solid-cystic mass with irregular density in retrorectal-presacral space.…”

Pleomorphic rhabdomyosarcoma of the submandibular gland: Diagnosis on a cytology sample

“…Due to controversial diagnostic criteria and similarities in clinical and imaging features between PRMS and other tumours, PRMS is often misdiagnosed. It mostly occurs in the deep soft tissue of the extremities and rarely in the head and neck region. Herein, we present a rare case of PRMS in the submandibular gland diagnosed by fine‐needle aspiration cytology (FNAC) and ancillary methods.…”

“…PRMS is often misdiagnosed or missed entirely owing to its nonspecific clinical and radiological findings . In addition, currently, there is no established diagnostic and therapeutic approach for PRMS.…”