a 45-year - old man presented with binocular diplopia in primary gaze for 1 year without any other ocular or general complaints . pupillary reflexes were normal , slit - lamp examination was unremarkable and there was no proptosis ( hertel exophthalmometry readings : 11 mm both eyes ) , ptosis or eyelid swelling . orthoptic evaluation showed 10-prism diopter right eye hypotropia and 6-prism diopter right eye esotropia on cover test for near fixation . the elevation and abduction of the right eye were clinically restricted . hess charting of the right eye showed restricted elevation in abduction ( 12 ) and restricted abduction ( 5 ) . hess charting of the left eye showed increased elevation in adduction ( 9 ) and increased adduction ( 4 ) [ fig . 1 ] . computed tomographic ( ct ) scan of the orbit demonstrated bilateral symmetrical enlargement of the medial rectus and inferior rectus muscle bellies [ fig . 2 ] . physical examination revealed enlarged hands , coarse facial features and macrognathia [ fig . 3 ] . diagnosis of acromegaly was suspected and magnetic resonance imaging ( mri ) was performed , demonstrating a pituitary macroadenoma ( 12 mm ) within a deformed sella turcica [ fig . an elevated serum igf - i level and the failure of gh suppression after an oral glucose load biochemically confirmed the diagnosis of acromegaly . endocrinological work - up also revealed an associated non - insulin - dependent diabetes mellitus . thyroid gland was clinically enlarged and ultrasonography demonstrated a multinodular goiter . repeated thyroid function tests ( thyroid - stimulating hormone , free triiodothyronine , free thyroxine ) were normal . thyroid peroxidase antibody , thyroglobulin antibody and thyroid - stimulating hormone receptor antibody levels were normal . the results of the cover test and hess screen test remained unchanged during a 2-year follow - up . ( a and b ) axial and coronal ct scans demonstrate bilateral enlargement of the medial rectus and inferior rectus muscle bellies coarse facial features and macrognathia mri scan with gadolinium illustrates a pituitary macroadenoma ( arrow ) within a deformed sella turcica the clinical features of acromegaly develop insidiously over decades , often resulting in a delay of 710 years in diagnosis after the estimated onset of symptoms . early recognition is essential as effective therapies can prevent disease progression and return the lifespan to normal . decreased vision or visual field defects are the main presenting complaints that lead to the work - up and diagnosis of acromegaly in 5.7% of the patients . diplopia could be due to cranial nerve palsy or hemifield slide phenomenon . in our case , binocular diplopia was the presenting complaint that brought the patient to medical attention the diplopia was caused by the bilateral enlargement of the medial rectus and inferior rectus muscles and increased on ductions away from the mechanically restricted muscles . the extraocular muscles may be involved as part of the generalized organomegaly associated with acromegaly . muscle biopsy specimens of the quadriceps muscle in acromegaly showed a hypertrophy of type 1 fibers and atrophy of type 2 fibers . a pubmed search revealed two cases that have been reported previously with extraocular muscle enlargement as the presenting feature of acromegaly in combination with bilateral lower eyelid swelling or ptosis . clinically significant motility defects were previously unrecognized in patients with gh - secreting pituitary tumors . extensive endocrinological work - up was performed and all tests were negative regarding graves - basedow disease , the most common cause of extraocular muscle enlargement.[24 ] although we can not entirely exclude this disease , repeated laboratory testing during a 2-year follow - up was carried out and remained negative . gh and igf - i excess causes thyroid overgrowth , which is usually considered a typical aspect of the organomegaly developing in acromegaly . multinodular goiter is detected in 65% of patients and nodular goiter is toxic in 14% of patients . the most common nonthyroid causes of extraocular muscle enlargement are inflammatory , vascular , neoplastic and infectious processes . based on clinical presentation and ct scan of the orbit , the existence of these disorders is very unlikely . to our knowledge , this is the first report of a patient with acromegaly with binocular diplopia due to restrictive extraocular myopathy as the initial clinical complaint .
a 45-year - old man presented with binocular diplopia in primary gaze for 1 year . 
 orthoptic evaluation showed 10-prism diopter right eye hypotropia and 6-prism diopter right eye esotropia . the elevation and abduction of the right eye were mechanically restricted . 
 this was associated with systemic features suggestive of acromegaly . magnetic resonance imaging ( mri ) of the brain demonstrated a pituitary macroadenoma . 
 an elevated serum insulin - like growth factor i level and the failure of growth hormone suppression after an oral glucose load biochemically confirmed the diagnosis of acromegaly . computed tomography ( ct ) of the orbit demonstrated bilateral symmetrical enlargement of the medial rectus and inferior rectus muscle bellies . 
 all tests regarding graves - basedow disease were negative . 
 although rare , diplopia due to a restrictive extraocular myopathy could be the presenting symptom of acromegaly .