Paratesticular myofibroblastic lesion in a prepubertal child: a case report of a rare spindle cell tumor with testis-sparing management.

Paratesticular tumors are uncommon in the pediatric population and can represent a wide range of benign and malignant pathologies. We report the case of an otherwise healthy 2-year-old boy who presented with an asymptomatic right scrotal mass. Serial scrotal ultrasounds demonstrated a stable, well-circumscribed extratesticular lesion adjacent to the epididymal head with internal vascularity and normal bilateral testicular architecture. Serum tumor markers, including alpha-fetoprotein, beta-human chorionic gonadotropin, and lactate dehydrogenase, were within normal limits. There was no family history of malignancy or urologic conditions. Given persistent diagnostic uncertainty, surgical exploration was performed. Intraoperatively, a firm paratesticular mass arising from the tunica albuginea was identified and excised with preservation of the testis. Frozen section analysis revealed bland spindle cells without malignant features, allowing for testis-sparing management. Permanent histopathology demonstrated a well-circumscribed spindle cell lesion within a loose collagenous stroma with dystrophic calcifications. Immunohistochemistry showed positivity for smooth muscle actin and negativity for desmin, myogenin, MyoD1, β-catenin, S100, and anaplastic lymphoma kinase (ALK), supporting a diagnosis of benign myofibroblastic lesion, such as fibrous pseudotumor, and excluding inflammatory myofibroblastic tumor. To our knowledge, this case represents one of the earliest presentations of a benign paratesticular myofibroblastic lesion. This case underscores the importance of considering rare benign spindle cell lesions in the differential of paratesticular lesions in young children and the use of intraoperative frozen section to facilitate testis-sparing surgery and avoid unnecessary orchiectomy through careful multidisciplinary evaluation.