98th Annual Meeting DOG 2000

P 368

Osteoma of frontal sinus as a rare differential diagnosis of endocrine orbitopathy – a case report

L. Blomberg1, R. Gockeln1, B. Schwab2, B. Haubitz3, R. Winter1

Introduction: A 44-years-old female patient was send to our clinic with a diagnosis of an "endocrine orbitopathy with monolateral left exophthalmus" for an orbital decompressing surgery. She already had received several corticosteroid therapies and retrobulbar radiotherapy with a total dosis of 25 Gy. She had a known autoimmune thyroiditis.

Patient and Methods: The clinical examination showed the following results: visual acuity: OD: 0.9, OS: 0.7 (with best possible correction) Hertel`s exophthalmometer: OD 20 mm, OS 22 mm, a positive concomitant vertical deviation, lower position of OS of about 2 mm (Kestenbaum), diplopia at up gaze, a restricted motility of m. rectus sup. and m. obliquus inferior. At the upper orbital rim a painless, not movable mass could be palpated. MRI and spiral CT scan of the orbita showed a space occupying lesion, which grew through the orbital roof into the intraorbital space with a subsequent displacement of the ocular muscles. Endocrinologically, there was no hyper- or hypothyroidism detectable.

Results: Surgery was performed by an osteoplasty of the frontal sinus and occlusion of the osseous defect. Intraoperatively the diagnosis of a frontal sinus osteoma was established. The postoperative visual acuity remained stable. The exophthalmus, diplopia and the positive vertical deviation are improving.

Discussion: In case of resistance to a conventional therapy modality of endocrine orbitopathy, repeated orbital MRI and CT scans play a crucial role in the differential diagnosis of orbital pathology.

1Dept. of Ophthalmology, 2Department of ENT, and 3Dept of Neuroradiology, Medizinische Hochschule Hannover, Carl-Neuberg-Str. 1, D-30625 Hannover, Germany