Intradiploic Meningioma in the Lateral Orbital Wall: A Case Report

Orbital wall tumor is rare, but a variety of primary and secondary tumors involving the orbital wall have been reported [1,2]. Intradiploic meningioma is another rare tumor [3,4]. We treated a rare case of intradiploic meningioma in the lateral orbital wall.

A previously healthy 46-year-old man presented with gradually appearing exophthalmos and tearing in the left eye. The patient had no remarkable personal or family history. Although he had left exophthalmos, he showed full eye movement and normal visual acuity. Computed tomography (CT) revealed an intradiploic low-density tumor in the lateral orbital wall (Figure 1A). MRI revealed an iso-T1, high-T2 homogeneous tumor inside the lateral orbital wall (Figure 1B). The tumor showed homogenous enhancement (Figure 1C). Thallium-201 single-photon emission computed tomography (Tl SPECT) showed mild uptake into the tumor in an early image and washout in delayed image(Figure 2A, B). Technetium-99m Bone scintigraphy revealed hot uptake only in the tumor (Figure 2C).

We conducted a biopsy of the tumor before extensive surgical removal. Pathological diagnosis of the biopsy samples revealed that the tumor was psammomatous meningioma. Three weeks later, the patient underwent total tumor resection under general anesthesia. The periorbita, dura, and orbital contents were all intact and preserved. The lateral orbital wall was reconstructed using a titanium plate. The patient's postoperative course was uneventful, and the exophthalmos disappeared. Postoperative MRI and CT scans confirmed total removal of the tumor. The final pathological diagnosis of the resected tumor was also benign psammomatous meningioma. No recurrence has been observed to date.

Crawford et al. reviewed 36 reported cases of intradiploic meningioma. Orbital and frontoparietal regions are the most common locations of intradiploic meningioma [3]. Sphenoorbital meningiomas are intraosseous meningiomas at the base of the anterior and middle cranial fossa, involving the sphenoid wing and orbit associated with a intracranial carpet-like, soft tissue component [5,6]. In our case, the tumor located only in lateral orbital wall. And the tumor has no intracranial carpetlike soft tissue component. Classic triad of spheno-orbital meningiomas are ptosis, visual impairment and ocular paresis. In our case these symptoms were not observed. So the tumor in our case is not spheno-orbital meningioma. A literature review revealed that only 8 cases of intradiploic meningioma of the orbital wall have been reported in English literature [7-13] (Table 1). In all the reported cases of orbital intradiploic meningioma, except the present case, the tumor originated
at the orbital roof.

All the tumors were surgically removed, and no recurrence has been reported. The reconstruction methods have been mentioned only in 2 reports [10,11]. In these studies, the researchers used free calvarial bone flap graft for orbital reconstruction. Our case is the first reported case involving the use of a titanium plate for orbital reconstruction after intradiploic meningioma removal. The use of titanium plates has been associated with the risk of infection and deformity. Autologous bone transplantation necessitates another skin incision and removal of normal bone. In the case of malignant tumors, there is a possibility of recurrence and repeat surgery. We discussed with the patient and selected titanium plate reconstruction. The cosmetic and medical outcomes were satisfactory.

MRI was performed only in 2 patients. Nuclear medicine studies were conducted only in 2 patients. Tl SPECT findings of orbital intradiploic meningioma have not been previously reported. Tl SPECT is a functional imaging technique that facilitates diagnosis of tumor malignancy and activity [14]. An early Tl SPECT image mainly shows tumor blood flow, and a delayed image mainly shows tumor malignancy and activity [15]. The Tl SPECT findings in our patient were comparable to those of patients with benign meningioma showing high blood flow and low malignancy.

Rapidly growing skull tumors, such as chondrosarcoma, sometimes occur in the orbital wall [1,2]. Chondrosarcoma is an aggressive tumor with a high tendency for recurrence and is capable of distant metastasis. The orbital chondrosarcoma should be removed together with the eye ball and the orbital contents to prevent local recurrence. Our patient had normal visual acuity and eye movement. Pathological diagnosis of our patient's biopsy sample revealed that the tumor was an intradiploic meningioma. Therefore, eyeball removal was not required, and we could preserve his eye and normal vision.

Competing interests

The authors declare that they have no competing interests.

Publication history

Received: 22-May-20112 Accepted: 12-July-2012
Published: 16-July-2012