Girl evaluated for long-standing strabismus, ptosis

Previous surgery failed to correct the patient’s ocular alignment.

Mark E. Patron

Andre J. Witkin

A 12-year-old girl presented to the pediatric ophthalmology and strabismus service at the New England Eye Center for evaluation of long-standing strabismus and right eyelid ptosis.

The patient had been diagnosed with congenital esotropia as a child and underwent strabismus surgery for this condition. She was left with residual esotropia and received spectacles to correct the hyperopic component. Her parents noted that her strabismus was never fully corrected but had been stable until age 9 years, when she began to develop a left hypertropia. She subsequently underwent left superior rectus recession for the hypertropia and left lateral rectus resection for the residual esotropia by an outside surgeon. Her parents stated that her ocular alignment had not improved since the surgery and that a pre-existing right ptosis had progressively worsened (Figure 1).

The patient’s medical history was unremarkable. She was a product of twin gestation with otherwise normal birth history. Family history was negative for strabismus and positive for Graves’ disease. She had a history of amblyopia and hyperopia in her left eye.

Figure 1. The patient’s ocular alignment had not improved after prior surgery, and a pre-existing right ptosis had progressively worsened. Images: Swanic M, Strominger MB, Kapadia MK

Examination

Visual acuity was 20/20 in the right eye and 20/40 in the left amblyopic eye. Glasses prescription was +3 D in both eyes. She had minimal stereopsis on Titmus testing, in which she identified only two of the nine target images. Motility examination revealed restricted elevation of the right eye with full motility of the left eye. The patient had no afferent pupillary defect. Color vision was full in both eyes. Hertel measurements showed mild proptosis with measurements of 19 mm in the right eye and 16 mm in the left eye. Prism cover testing showed a relatively comitant 10 DD left hypertropia in all fields of gaze.

What is your diagnosis?

Left hypertropia, right proptosis

A patient presenting with this abnormal constellation of findings, including ocular motility disturbances, proptosis and worsening ptosis, requires careful evaluation.

Careful attention to motility quickly revealed that the left hypertropia was actually secondary to a process causing an elevation deficit in the contralateral eye. The presence of proptosis and ptosis suggested the possibility of a mass lesion. A short differential diagnosis of a space-occupying lesion in this age group includes encephalocele, mucocele, dermoid cyst, rhabdomyosarcoma, optic nerve glioma, metastatic tumor and lacrimal gland tumor.

The proptosis and motility disturbance could be suggestive of Graves’ disease. However, this diagnosis would be unlikely in a patient of this age group and also would be unlikely to cause ptosis. The patient underwent MRI imaging and also had thyroid function tests ordered as an initial workup.

Test results

Thyroid function tests, as expected, were negative. MRI of the orbit showed a large mass lesion in the region of the right lacrimal gland (Figures 2 to 4). The mass can be seen compressing the globe and displacing the superior rectus muscle. At this point, the patient was referred to the oculoplastics service for further evaluation of the lesion.

Figures 2-4. MRI of the orbit showed a large mass lesion in the region of the right lacrimal gland.

The oculoplastic surgeon elected to perform an excision of the lesion in combination with the neurosurgery department. The lesion was too large to be removed by lateral orbitotomy, so neurosurgery assisted with a craniotomy approach. This approach made for good exposure of the lesion, allowing it to be removed in its entirety without breaking its capsular component (Figure 5).

Figure 5. The lesion was removed with a craniotomy approach, allowing it to be removed in its entirety without breaking its capsular component.

On histopathological examination, the lesion had a pseudocapsule and was primarily made of ductules with a double cell layer (Figure 6). The smooth muscle actin stain of the mesenchymal tissue was positive, showing the tissue’s myoepithelial cell lineage (Figure 7). This constellation of findings led to a diagnosis of pleomorphic adenoma.

Figure 6. Histopathological examination showed the lesion had a pseudocapsule and was primarily made of ductules with a double cell layer.

Figure 7. The smooth muscle actin stain of the mesenchymal tissue was positive, showing the tissue’s myoepithelial cell lineage.

Discussion

Lacrimal gland tumors comprise only 10% of space-occupying orbital lesions; 80% of these tumors are inflammatory or lymphoid, while 20% are epithelial. More than half of these epithelial lesions — about 55% — are benign. Pleomorphic adenoma is the most common benign tumor, while adenoid cystic carcinoma is the most common malignant epithelial lesion.

Pleomorphic adenoma is uncommon in this age group. However, there have been six prior case reports in the literature of pleomorphic adenoma afflicting the pediatric population. The youngest patient was diagnosed at age 6 years. The median age at diagnosis of pleomorphic adenoma is 35 years.

Pleomorphic adenoma is a slow-growing tumor, and CT scan typically shows a round mass that may remodel bone but rarely erodes it. Pleomorphic adenomas have a pseudocapsule, meaning that no epithelial lining separates them from surrounding tissue. In contrast, adenoid cystic carcinoma does not have a capsule and can erode bone on CT scan.

Since undergoing excision of her lesion, the patient’s proptosis and motility have improved considerably. She is still being followed at present.

References:

• Bernardini FP, Devoto MH, Croxatto JO. Epithelial tumors of the lacrimal gland: an update. Curr Opin Ophthalmol. 2008;19(5):409-413.
• Fenton S, Sie Go DM, Mourits MP. Pleomorphic adenoma of the lacrimal gland in a teenager, a case report. Eye. 2004;18(1):77-79.
• Lai T, Prabhakaran VC, Malhotra R, Selva D. Pleomorphic adenoma of the lacrimal gland: is there a role for biopsy? Eye. 2009;23(1):2-6.
• Laskawi R, Schott T, Schröder M. Recurrent pleomorphic adenomas of the parotid gland: clinical evaluation and long-term follow-up. Br J Oral Maxillofac Surg. 1998;36(1):48-51.
• Shields JA, Shields CL, Scartozzi R. Survey of 1264 patients with orbital tumors and simulating lesions: The 2002 Montgomery Lecture, part 1. Ophthalmology. 2004;111(5):997-1008.

• Matthew Swanic, MD, Mitchell B. Strominger, MD, and Mitesh K. Kapadia, MD, PhD, can be reached at New England Eye Center, Tufts University School of Medicine, 750 Washington St., Box 450, Boston, MA 02111; 617-636-4219; fax: 617-636-4866; Web site: www.neec.com.

• Edited by Mark E. Patron, MD, and Andre J. Witkin, MD. Drs. Patron and Witkin can be reached at New England Eye Center, Tufts University School of Medicine, 750 Washington St., Box 450, Boston, MA 02111; 617-636-4219; fax: 617-636-4866; Web site: www.neec.com.