Ocular Hypertropia Mimicking Inferior Rectus Palsy as an Atypical Presentation of Parameningeal Rhabdomyosarcoma in a Child.

Introduction: Rhabdomyosarcoma (RMS) originates from undifferentiated mesenchymal cells that give rise to striated muscles. The symptoms of para-meningeal RMS often resemble those of allergic rhinosinusitis, including nasal congestion, mucus discharge, headache, and occasional nosebleeds. We report a child with atypical clinical presentation of ocular hypertropia secondary to para-meningeal RMS.

Case presentation: A child presented with an upward deviation of the left eye. He had a history of blunt trauma to the face before 5 days. Computed tomography (CT) of the head revealed a soft tissue density involving the left maxillary sinus. The magnetic resonance imaging (MRI) showed a 37.6 mm x 38.4 mm lesion within the left maxillary sinus extending to the orbit, nasal cavity, and premaxillary and retro maxillary areas with a heterogeneous signal and mild heterogeneous enhancements. A biopsy and histopathology confirmed alveolar RMS. The child was treated with chemotherapy and radiotherapy.

Conclusion: Pediatric RMS with orbital extension mimicking benign conditions is challenging to diagnose and manage. Hypertropia following eye trauma can obscure severe underlying conditions, such as para-meningeal RMS. The inferior rectus lesion mimicking inferior rectus palsy stresses a thorough evaluation, including imaging and biopsy. Early and accurate diagnosis is crucial for the effective management of children with such aggressive malignancy.