[Unilateral exophthalmos caused by a prolactin producing ectopic pituitary adenoma: case report]

We report a case of a patient with a prolactin (PRL) producing ectopic pituitary adenoma presenting a unilateral exophthalmos.

This 70-year-old woman presented an ophthalmologist with progressive left-sided exophthalmos over the previous 2 months. Bone window CT scan revealed extensive bony destructions of the skull base including the clivus, sphenoid sinus and medial aspect of the middle cranial fossa. Gd-DTPA MRI revealed an abnormal enhancement lesion in the sphenoid sinus, but no abnormal enhancement was seen in the sella turcica. Since these findings suggested malignant tumors of the cranial base, several biopsies through the transnasal route were carried out to confirm the diagnosis. This procedure caused the complication of cerebrospinal fluid (CSF) leakage. Because the biopsy specimen revealed a PRL producing adenoma (serum PRL-level 645.7 ng/ml), the patient was admitted to our department. On admission neurological examination showed an exophthalmos with external ocular movement disorders and disturbance of visual acuity on the left side. She underwent transsphenoidal surgery to remove the tumor and to reconstruct the sphenoid sinus and the sellar floor. Surgical exploration revealed a yellowish and soft tumor underneath the normal mucous membrane in the sphenoid sinus. The sellar floor was destructed extensively, but the dura mater of the pituitary fossa was intact except for a small pin-hole which was thought to be produced during the several biopsy procedures. No surgical procedure was applied to the intrasellar region. The sphenoid sinus was packed with a piece of fascia and fat applied with the aid of fibrin glue to prevent CSF leakage.

The patient followed a satisfactory postoperative course. Her visual acuity disturbance and exophthalmos disappeared one year after surgery. Postoperative serum PRL level remained high (66.9 ng/ml), but, subsequently, was normalized (9.5 ng/ml) with a bromocriptine therapy (15 mg daily).

As far as we are aware, this is the first case report of an ectopic pituitary adenoma causing unilateral exophthalmos. Although it is extremely rare, pituitary adenomas should be kept in mind in a differential diagnosis of exophthalmos.