A Case in Which the Endoscopic Denker's Approach Was Useful in the Diagnosis of IgG4-Related Ophthalmic Disease

Abstract

IgG4-related disease (IgG4-RD) is a chronic inflammatory condition characterized by elevated serum IgG4 levels, infiltration of IgG4-positive plasma cells, and fibrosis in various organs. We report the case of a 76-year-old man who presented with left-sided proptosis. Computed tomography revealed a mass lesion in the left orbit. An initial biopsy via a transnasal approach under local anesthesia was inconclusive. Although endoscopic sinus surgery was performed under general anesthesia, a definitive diagnosis could not be obtained. The lesion continued to enlarge, and subsequent ophthalmologic examinations revealed progressive optic nerve compression. Therefore, tumor resection was performed again under general anesthesia using the endoscopic Denker's approach. The tumor was successfully resected without complications. Histopathological findings led to a diagnosis of probable IgG4-related ophthalmic disease (IgG4-ROD). Following surgery, the residual lesion enlarged again; however, a three-day course of steroid pulse therapy resulted in reduction of the lesion and improvement of optic nerve compression. The patient has remained relapse-free. While 81% of IgG4-ROD cases involve the lacrimal gland, other orbital structures such as the pterygopalatine fossa, trigeminal nerve branches, extraocular muscles, orbital fat, eyelids, and nasolacrimal duct can also be affected. In cases without lacrimal gland involvement, the optimal approach for obtaining diagnostic biopsy specimens should be considered individually. Although there is no consensus on the required volume of tissue for diagnosis, we believe that aggressive resection of the central lesion is necessary for accurate diagnosis. The endoscopic Denker's approach facilitates wide exposure and resection of far lateral maxillary sinus lesions, enabling both decompression and definitive diagnosis, which can lead to appropriate subsequent treatment.

Keywords: endoscopic sinus surgery; optic nerve compression; orbital tumor; probable; steroids.

Figure 1. Clinical Photographs and Nasal Endoscopic Images

A: Frontal view showing mild left proptosis. B: Superior view also demonstrating mild left proptosis. C: Nasal endoscopy of the left superior nasal cavity showing the absence of the superior and middle turbinates. D: Endoscopic view of the left inferior nasal cavity, where the inferior turbinate appears slightly atrophic.

Figure 2. Paranasal Sinus CT Images

A: CT scan taken 15 years prior showing an intact medial orbital wall with no evidence of orbital mass; medial rectus and optic nerve appear normal. B: Initial CT at presentation revealing a 45 × 18 mm mass (arrowhead) along the medial wall of the left orbit, invading into the sinus and showing unclear margins with the medial rectus and optic nerve. C: Coronal CT eight months after first surgery showing tumor progression, with invasion into the medial rectus, superior oblique, and inferior rectus muscles; the mass occupies half of the orbit and compresses the optic nerve (arrowhead). D: Postoperative CT after second surgery showing substantial tumor removal; however, residual tumor remains in the anterior and lateral orbit (arrowhead).

Figure 3. Paranasal Sinus MRI Images

A: T1-weighted image showing isointense orbital mass (arrowhead) appearing to invade the medial rectus. B: T2-weighted image showing the mass as hypointense (arrowhead).

Figure 4. Intraoperative Views from the First Endoscopic Sinus Surgery

A: Observation of the medial orbital wall from the nasal cavity; nasal mucosa was removed to expose the tumor. NS: Nasal septum; Sb: Skull base; Ch: Choana; T: Tumor. B: Tumor incised with a crescent knife; no bleeding observed. C: Part of the orbital tumor was removed with forceps; the mass was white and firm.

Figure 5. Intraoperative Views from the Second Surgery Using the Endoscopic Denker's Approach

NS: Nasal septum; IT: Inferior turbinate; T: Tumor; NN: Nasal notch. A: Incision made anterior to the inferior turbinate at the level of the piriform aperture. B: Infraorbital nerve (arrowhead) and artery (arrow) identified; artery was cauterized and divided. C: Soft tissue around the nasal notch was dissected, and bone was drilled. D: Nasolacrimal duct (arrowhead) was displaced medially to expose the orbital floor. E: Orbital floor and remaining medial wall were drilled to widely expose the orbital tumor. F: Tumor was removed in segments, separated from the inferior rectus muscle (arrowhead). G: Tumor debulked, revealing the medial rectus muscle (arrowhead). H: Bone removal extended near the optic nerve; tumor was maximally resected, and the surgery was completed.

Figure 6. Histopathological Findings of the Excised Orbital Tumor

A: Dense fibrous connective tissue with focal aggregation of plasma cells (arrowhead). B: IgG4-positive plasma cells accounted for more than 50% of IgG-positive cells, with up to 25 cells per high-power field (HPF).