Hit the mark with diffusion-weighted imaging: metastases of rhabdomyosarcoma to the extraocular eye muscles
1 Department of Paediatric Radiology, Institute of Diagnostic and Interventional Radiology, Josef-Schneider-Straße 2, Wuerzburg 97080, Germany
2 Department of Neuroradiology, Institute of Diagnostic and Interventional Radiology, Josef-Schneider-Straße 11, Wuerzburg 97080, Germany
3 Department of Paediatrics, Josef-Schneider-Straße 2, Wuerzburg 97080, Germany
4 Department of Nuclear Medicine, Oberduerrbacher Straße 6, Wuerzburg 97080, Germany
5 Institute of Pathology, Josef-Schneider-Straße 2, Wuerzburg 97080, Germany
BMC Pediatrics 2014, 14:57 doi:10.1186/1471-2431-14-57Published: 27 February 2014
Rhabdomyosarcoma is the most frequent malignant intraorbital tumour in paediatric patients. Differentiation of tumour recurrence or metastases from post-therapeutic signal alteration can be challenging, using standard MR imaging techniques. Diffusion-weighted MRI (DWI) is increasingly considered a helpful supplementary imaging tool for differentiation of orbital masses.
We report on a 15-year-old female adolescent of Caucasian ethnicity who developed isolated bilateral thickening of extraocular eye muscles about two years after successful multimodal treatment of orbital alveolar rhabdomyosarcoma. Intramuscular restricted diffusion was the first diagnostic indicator suggestive of metastatic disease to the eye muscles. DWI subsequently showed signal changes consistent with tumour progression, complete remission under chemoradiotherapy and tumour recurrence.
Restricted diffusivity is a strong early indicator of malignancy in orbital tumours. DWI can be the key to correct diagnosis in unusual tumour manifestations and can provide additional diagnostic information beyond standard MRI and PET/CT. Diffusion-weighted MRI is useful for monitoring therapy response and for detecting tumour recurrence.