A Case of Pediatric Paratesticular Rhabdomyosarcoma with Epididymitis
A 10-year-old boy presented to the outpatient department of urological services with painful swelling in the scrotum on the right side that had lasted for 2~3 days. The medical history of the patient was unremarkable. Physical examination revealed a mild tenderness and erythema of the hemi-scrotum on the right side. Scrotal ultrasound at presentation reportedly demonstrated that the right epididymis showed massive swelling (4 cm×3 cm) with marked increased vascularity and suspicious for severe epididymitis with the need to diagnose the epididymal tumor like as adenomatoid tumor differentially. Therefore, the boy was discharged with antibiotics and instructions to follow up in case symptoms persisted. After 2 weeks, he returned to the outpatient department with persistent pain and swelling. He was hospitalized for further evaluation and an exploratory operation. Laboratory evaluation showed mild leukocytosis and normal lactate dehydrogenase, α-fetoprotein, and β-human chorionic gonadotropin. The surgical findings indicated that there was no abscess in the right scrotum but mild adhesion due to inflammation except hard epididymal mass. We conducted excisional biopy for the mass. The pathologist determined that although the tissue specimen was not large enough to confirm diagnosis, the hard mass was at least low grade sarcoma. Subsequently abdominopelvic computed tomography and chest radiography revealed no metastases. Magnetic resonance imaging of the testis showed a large epididymal mass (5 cm×4 cm×6 cm) on the right side was well-demarcated and heterogeneously enhanced (). The following week, the patient underwent right radical orchiectomy and hemiscrotectomy given tumor inavsion of the scrotal wall. Macroscopic examination showed that the large epididymal mass was an enlarged and well-demarcated yellow myxoid solid tumor (5.5 cm×4.5 cm) with hemorrhagic change and focal necrosis. Normal testicular tissue was expelled peripherally (). The tunica albuginea and testis had not been invaded by the tumor, and the surgical margin was also negative. Microscopic examination demonstrated a highly cellular tumor composed of rhabdomyoblasts and pleomorphic cells with ovoid hyperchromatic nuclei and containing eosinophilic cytoplasm (). As seen on an immunohistochemical stain, the tumor was diffusely and strongly positive for desmin and MyoD1. In conclusion, because there was no evidence of metastasis, the patient was classified into group I of the Intergroup Rhabdomyosarcoma Study (IRS). He underwent 3 cycles of adjuvant chemotherapy (VAC regimen: vincristine 1.5 mg/m2 on day 8 IV; dactinomycin 1.5 mg/m2 on day 8 IV; and cyclophosphamide 150 mg/m2 IM on day 1~7). At 1 year of follow-up, we found him to be disease free.