Granular Cell Tumor of the Orbit: Review of the Literature and a Proposed Treatment Modality

Abstract

To document a unique case of granular cell tumor of the orbit, located lateral to and abutting the optic nerve, that benefited from treatment with proton beam irradiation, with a comprehensive review of the literature on granular cell tumor of the orbit.Methods: Clinicopathologic case report with detailed imaging features and histopathologic and immunohistochemical evaluation for cytoplasmic tumor biomarkers differentiating granular cell tumor (GCT) from it mimicking lesions with relevant literature citations. The authors reviewed 20 cases of orbital GCT from 2011 to 2020 in addition to 40 cases from 1948 to 2011 and included a summary of imaging and clinical features, outcomes, and recommended treatment modalities.Results: A 32-year-old man with 1-year history of left retrobulbar pain and diplopia on lateral gaze, intermittent left eyelid swelling, and a tonic left pupil was found to have a fusiform intraconal mass extending toward the orbital apex and abutting the optic nerve. Histopathologic and immunohistochemical investigations collectively supplied data diagnostic of a GCT with an initial low proliferation rate. GCT is a soft tissue neoplasm that originates in the nervous system and can occur anywhere in the body. This enhancing tumor is isointense to gray matter on T1-weighted MRI, hypointense on T2. After an incisional biopsy, the patient's symptoms persisted, and follow-up imaging several months later revealed further growth of the mass. The impossibility of complete surgical removal prompted the decision to treat with proton beam radiation therapy, which resulted in substantial regression in the size of the residual tumor. Most frequently involving the inferior rectus muscle (42%), orbital GCT is usually benign with only 4 reported cases of malignant orbital GCT (7%). Wide surgical resection with complete removal is usually curative for benign orbital GCT, and proton beam radiation therapy can aid in tumor shrinkage.Conclusions: GCT should be considered in the differential diagnosis when encountering patients with mass lesions RESULTSClinical History. A 32-year-old male was initially seen at another institution with a history of left retrobulbar pain. He also complained that his left pupil was larger than the right. CT at the time demonstrated a fusiform intraconal mass located lateral to and abutting the optic nerve. It

Granular Cell Tumor in the Medial Rectus Muscle: A Case Report

“…We report a case of granular cell tumor in the medial rectus muscle. Granular cell tumor developing in the orbit is rare, and there had been 60 reported cases of orbital granular cell tumor so far [1].…”

“…Our case was an 80-year-old female, and the mean age of presentation is found to be 44 years [1]. Overall, granular cell tumors predominantly occur in females [1-3], but there is an equal distribution between sexes in cases with orbital granular cell tumor [1].…”

“…Our patient showed restriction of adduction and abduction in accordance with involvement of the medial rectus muscle. In approximately 70% of the cases with orbital granular cell tumor, a lesion directly involves the extraocular muscles [1, 6]. As the tumors have neural origin and develop in association with small-to-medium-sized nerves, predilection for involvement of the extraocular muscles is due to dense neural supply to the muscles [1].…”

“…In approximately 70% of the cases with orbital granular cell tumor, a lesion directly involves the extraocular muscles [1, 6]. As the tumors have neural origin and develop in association with small-to-medium-sized nerves, predilection for involvement of the extraocular muscles is due to dense neural supply to the muscles [1]. Positive S100 immunohistochemical stain implies the neurogenic nature of granular cell tumor [1].…”

“…As the tumors have neural origin and develop in association with small-to-medium-sized nerves, predilection for involvement of the extraocular muscles is due to dense neural supply to the muscles [1]. Positive S100 immunohistochemical stain implies the neurogenic nature of granular cell tumor [1]. The most frequently involved muscle is the inferior rectus muscle, followed by the medial and superior recti muscles [1, 6].…”