Optic nerve head drusen mimicking optic nerve tumor.

Dear Editor,

Optic nerve head drusen (ONHD) are laminated hyaline bodies within the optic nerve head. Spectral-domain optical coherence tomography (SD-OCT) is a noninvasive optical imaging technique that provides high-resolution cross-sectional images of the retina, optic nerve head and retinal nerve fiber layer thickness. This technique thus offers several advantages in the diagnosis of ONHD through the direct visualization of ONHD and the analyses of retinal nerve fiber layer profiles [1,2,3]. Visual impairment due to ONHD is rare, thus its differential diagnosis from other serious diseases is very important. We found ONHD in a patient referred with diagnosis of optic nerve tumor.

A 45-year-old woman was referred for the evaluation of an optic nerve tumor found during routine visual acuity testing. Fundus examination showed yellowish amorphous material around the right optic disc (Fig. 1A). Fluorescein angiography showed hyperfluorescent staining around the optic disc (Fig. 1B). SD-OCT showed hyper-reflective retinal masses with irregular internal reflectance and posterior shadowing (Fig. 1C), compatible with ONHD.

Fig. 1

(A) Fundus photograph shows yellowish amorphous material around the optic disc. (B) Fluorescein angiography shows hyperfluorescent staining around the optic disc. (C) Spectral-domain optical coherence tomographic scan (Spectralis OCT; Heidelberg engineering, Heidelberg, Germany) showing hyper-reflective retinal masses (optic disc drusen, arrows) with irregular internal reflectance and posterior shadowing.

Differential diagnosis of yellowish amorphous material around the optic disc may include Leber's miliary aneurysm, Coats' disease, retinal cavernous hemangioma or ONHD [4]. Patients with Leber's miliary aneurysm and Coats' disease are typically young men [4]. Leber's miliary aneurysm, Coats' disease or retinal cavernous hemangioma show dilated capillaries and telangiectasia, most commonly located in the mid-periphery of superotemporal quadrants of the retina [4]. These findings are contrary to those in our patient, a middle-aged woman who presented with nasally-located peripapillary masses. In addition, fluorescein angiography tends to reveal leakage in patients with Leber's miliary aneurysm, Coats' disease or retinal cavernous hemangioma [4], in contrast to the staining findings of our patient.

Ultrasonography is considered the gold standard method for the diagnosis of ONHD; however, it definitely has worse resolution than SD-OCT. SD-OCT began a new era in the diagnosis of ONHD [1,2]. An association between older age and visible ONHD has been determined [3]. In agreement with this finding, the present patient was 45 years of age. ONHD can be complicated by hemorrhage [5] but does not usually require treatment.

In conclusion, ONHD should be considered in the presence of peripapillary masses, and SD-OCT can be helpful for such a diagnosis. Recognition of peripapillary masses as a symptom of ONHD will reduce the occurrence of unnecessary treatment.