Abstract
RATIONALE: Occurrence of granulosa cell tumors (GCTs) in the eye are rare and may be diagnosed by imaging examination and immune-histochemical studies. Two common signs of a rectus muscle tumor are the proptosis of the eye ball and the complaint of bi-ocular diploma. PATIENT CONCERNS: A 45-year-old man visited our ophthalmology department with an about a 3-year history of vertical diplopia. His visual acuity when looking forward was normal but was severely low when gazing upward. DIAGNOSIS: Histopathological analysis demonstrated that the encapsulated tumor contained large nested or cord-like cells with small nuclei and abundant eosinophilic cytoplasmic particles. Immunohistochemistry showed that tumor cells strongly expressed CD68, S100 and vimentin, were weakly positive for Ki67, and negative for CK. The tumor was diagnosed as a GCT. INTERVENTIONS: The tumor was surgically removed via a transconjunctival approach along inferior rectus muscle. OUTCOMES: The severe loss of acuity when gazing upward was ameliorated after surgery, but global mobility did not improve. Long-term follow-up was still needed. LESSONS: Ophthalmologists should be aware that when a patient's visual acuity is normal when looking forward but severely low when gazing upward, it may be a sign of a GCT of the inferior rectus muscle.