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Department of Ophthalmology, Blanton Eye Institute, Houston Methodist Hospital, Houston, TXDepartment of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, TXDepartments of Ophthalmology and Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, NYDepartment of Ophthalmology, Baylor College of Medicine, Houston, TX
Department of Ophthalmology, Blanton Eye Institute, Houston Methodist Hospital, Houston, TXDepartment of Ophthalmology, Baylor College of Medicine, Houston, TXDepartment of Ophthalmology and Visual Sciences, The University of Texas Medical Branch, Galveston, TXUT MD Anderson Cancer Center, Houston, TXDepartment of Ophthalmology, University of Iowa Hospitals and Clinics, Iowa City, IADepartments of Ophthalmology, Neurology, and Neurosurgery, Weill Cornell Medical College, New York, NY
Internuclear ophthalmoplegia (INO) is caused by a lesion in the medial longitudinal fasciculus (MLF). It is characterized clinically by an ipsilateral adduction deficit (e.g., adduction deficit or lag) and a dissociated, horizontal, abducting nystagmus of the contralateral eye on attempted horizontal gaze. A similar clinical presentation not attributable to a lesion in the MLF, called a pseudo-INO, is usually caused by myasthenia gravis. We present a rare case of an apparent INO resulting from rectal adenocarcinoma metastasis to the orbit. To our knowledge, there are only 13 other reports of orbital metastasis resulting from colorectal cancer (of which only 6 were rectal cancer).
We believe that this is the first reported case mimicking an apparent INO.
Case
A 69-year-old male patient presented with a 3-week history of double vision, headache, and left eye pain. He had hypertension and hyperlipidemia. His medications were verapamil and over-the-counter nonsteroidal anti-inflammatory drugs. One month before presentation, he reported anorexia, polydipsia, polyuria, and weight loss. He had a 15 pack-year smoking history but had quit tobacco use 30 years previously. He drank 1–2 ounces of whiskey every other day. Family history was positive for coronary artery disease in his father.
Neuro-ophthalmology examination showed a visual acuity of 20/20 OU. The pupils were isocoric without a relative afferent pupillary defect. External examination showed no ptosis or lid retraction. Motility examination revealed a significant bilateral and asymmetric upward gaze restriction OU, OD > OS (Fig. 1). There was a primary position exotropia of about 10 prism diopters (PD) with a significant underaction of adduction of the right eye and an incomitant exotropia (>40 PD of exotropia) in right gaze. There was lid retraction in attempted gaze to the right, which was believed to be caused by mechanical restriction and exaggerated effort. Exophthalmometry showed bilateral proptosis. Intraocular pressure measurements, visual field testing, slit-lamp biomicroscopy, and ophthalmoscopy were normal OU.
Fig. 1Ocular movements exhibit a left adduction deficit (pseudo-internuclear ophthalmoplegia) upon rightward gaze, restriction of upward gaze, and exotropia OD > OS in primary gaze.
Laboratory testing showed mildly elevated serum leukocyte counts and elevated liver function studies, including alkaline phosphatase and alanine/aspartate aminotransferase levels. A hepatitis panel was negative. Findings of thyroid function studies were normal.
Brain computed tomography (CT) scan without contrast and magnetic resonance imaging (MRI) with/without contrast as well as diffusion weighted images were normal and showed no lesion of the MLF, and there was no evidence of stroke.
Review of the orbital and brain CT scan showed a small nodular mass involving the posterior aspect of the left medial rectus muscle (Fig. 2). Orbital MRI with/without contrast exhibited an 8 mm enhancing mass involving the left medial rectus and an 8 mm mass involving the right superior oblique. An additional 13 mm mass was noted in the left masseter muscle.
Fig. 2Axial T1-weighted magnetic resonance imaging of the orbit with contrast, revealing an 8 mm enhancing mass involving the left medial rectus (red circle) and a similar mass involving the right superior oblique. Also note that there is no lesion in the dorsal midbrain or medial longitudinal fasciculus to account for a true internuclear ophthalmoplegia. The lid retraction in gaze right was believed to be caused by mechanical restriction and effort.
CT scans of the chest, abdomen, and pelvis revealed multiple spiculated pulmonary nodules; lytic lesions of the iliac crest, lumbar spine, and thoracic vertebrae T3 vertebral body; and hypodense lesions scattered throughout the liver. Wall thickening was noted in the right aspect of the rectum. Positron emission tomography–CT imaging showed hypermetabolic osseous lesions consistent with the abnormalities noted on the body CT scan and prominent uptake in the skeletal muscles.
Colonoscopy revealed a rectal mass that was biopsied and indicated a small focus of low-grade moderately differentiated adenocarcinoma of the colon (Fig. 3). Additional biopsies of a soft tissue mass from the right lateral thigh, the liver, and the right orbital mass revealed infiltration by similarly graded masses. The various biopsies showed the same histologic characteristics and stained positive for CDX-2 and CK-20 and negative for CK7 and TTF1, indicating metastatic colorectal adenocarcinoma.
Fig. 3Histopathology of rectal biopsy showing neoplastic glands infiltrating the submucosal stroma (A) and with intravascular permeation (arrows) (B), consistent with a low-grade moderately differentiated adenocarcinoma of the colon (hematoxylin and eosin stain; original magnification 20×).
Typically, an acute, isolated, unilateral or bilateral adduction deficit with an incomitant exotropia, especially in the setting of a dissociated horizontal abducting nystagmus on contralateral gaze, is an INO. In our patient, there was a subtle asymmetric bilateral upgaze restriction and the presence of lid retraction in attempted adduction OS. This was believed to be caused by mechanical restriction and exaggerated effort to adduct the eye rather than aberrant regeneration of the lid. We believe that this might be an additional clinical clue to the diagnosis of possible orbital disease in patients with similar ophthalmoplegia. In our case, however, the patient had findings mimicking an INO but was found to have multiple orbital masses that proved to be rectal carcinoma metastasis. Orbital metastases are rare (2%–3% of cancer patients), and these patients may present with diplopia, pain, visual loss, proptosis, and eyelid swelling.
Of the 13, only 6 cases involve rectal carcinoma as the primary tumour. However, it has been hypothesized that gastrointestinal carcinoid tumours have a propensity to metastasize to the extraocular muscles.
Treatment of orbital metastatic disease is primarily aimed at preserving visual function and palliating pain. Radiotherapy is the mainstay treatment, but treatment can also include corticosteroids, chemotherapy, hormonal therapy, and surgery.
To our knowledge, this is a rare and unique presentation of metastasis as an apparent INO. Orbital metastasis from colorectal carcinoma is uncommon but should be considered in cases of mass effect in the orbit.
Disclosure
The authors have no proprietary or commercial interest in any materials discussed in this article.
References
Cherif E.
Ben Hassine L.
Azzabi S.
Khalfallah N.
Orbital metastasis as the inaugural presentation of occult rectal cancer.
Only treatment affecting the orbital metastasis is noted.
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