Your Diagnosis, Please
A previously healthy 12-year-old girl from the United Arab Emirates (UAE) was admitted to a tertiary care hospital in Singapore for evaluation and treatment of gradually increasing left eye proptosis and subsequent blurred vision at extreme points of conjugate gaze. Three months earlier, she had presented to physicians in the UAE with left eye protrusion 1 day after the sap from a fig had splashed directly into her left eye. Her eye became red and itchy. Despite rinsing her eye out immediately, she noticed proptosis the next day.
Two months later, the family traveled to India, where computed tomography scan and magnetic resonance imaging were performed, revealing a left retro-orbital space-occupying lesion, the appearance of which was suggestive of an orbital rhabdomyosarcoma. Excisional surgery was recommended at that time, but her parents declined and decided to seek another medical opinion at our hospital in Singapore. She had no associated eye or facial pain, paresthesia or numbness. She had no headache, fever, appetite loss, weight loss or systemic symptoms. There was no other preceding illness or traumatic injury to the left eye. She had an unremarkable perinatal history, normal developmental milestones and a complete immunization history. There was no history of exposure to animals or unpasteurized milk. She was the seventh child of nonconsanguineous parents. There was no significant family history.
On examination, she appeared well and comfortable. Vital signs showed a tympanic temperature 36.8°C, heart rate of 90 beats/min, respiratory rate of 18 breaths/min, blood pressure of 95/58 mm Hg and oxygen saturation of 99% in ambient air. She had no clubbing, pallor or jaundice. There was no goiter. She was thin for her age: height was 142 cm (10th to 25th percentile), weight was 28.8 kg (3rd centile). Physical examination showed marked unilateral proptosis of her left eye with diplopia on upward and downward gaze. Pupillary response, extraocular movements and visual fields were intact. Fundoscopy showed bilateral normal optic discs. The patient had no other focal neurologic deficits. She had bilateral small, nontender, mobile and firm cervical lymphadenopathy. There was no supraclavicular, axillary or inguinal lymphadenopathy. Cardiac, respiratory, abdominal and skin examinations were normal.
Initial laboratory studies showed white blood cell count of 4.44 × 109/L (differential count of 42.5% neutrophils, 24.1% lymphocytes, 13.1% monocytes, 19.4% eosinophils, 0.9% basophils), hemoglobin of 12.9 g/dL and platelet count of 212 × 109/L. Erythrocyte sedimentation rate was 26 mm/h, and C-reactive protein was <5 mg/L. Complete liver panel, renal panel and fasting glucose blood tests were normal. Cerebrospinal fluid protein, glucose, cell count and culture results were normal. Bone marrow aspirate revealed no metastatic infiltration, and normocellular eosinophilia comprising 20% of all nucleated cells. HIV antibody test was negative. Repeat magnetic resonance imaging of the orbits and brain revealed a large mass lesion centered on the left sphenoid portion of the skull base, extending to involve the orbit, pterygo-palatine fossa, masticator space and intracranial space (Fig. 1). PET computed tomography showed no fluorodeoxyglucose-avid lesions elsewhere. Biopsy of the orbital mass was performed.