Orbital myxoma: A case report

INTRODUCTION

Myxomas are rare, benign neoplasms of mesenchymal origin.[1] Although benign, these tumors are locally aggressive with a high rate of recurrence following conservative resection.[1] Their relative infrequency, variable location, and insidious growth present a diagnostic challenge.

Myxomas have been described throughout the body, but within the head-and-neck region, they most often occur in the mandible and less commonly in the maxilla.[1,4,7] Intraosseous myxomas outside of these regions are exceedingly rare. We describe the clinical presentation, diagnostic evaluation, and surgical management of a middle-aged male who presented with chronic sinusitis and a supraorbital intraosseous myxoma.

MATERIALS AND METHODS

We report a case of a 53-year-old male who presented with a history of chronic sinusitis after the failure of three courses of antibiotics. Initial symptoms included 3 months of purulent rhinorrhea, hyposmia, cough, and bifrontal headache.

Physical examination was unremarkable and extraocular movements were intact.

Computed tomography and magnetic resonance imaging were subsequently obtained. Imaging revealed a 2.4 × 2.7 × 2.2 cm expansile lesion involving the bony superior and lateral orbit [Figure 1a-d].

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Figure 1:: (a and b) Coronal and axial views of non-contrast computed tomography sinus revealing a 2.4 × 2.7 × 2.2 cm expansile lesion involving the bony superior and lateral orbit. There are cortical thinning and loss of portions of the cortical margin, expansion into the left anterior cranial fossa table, and a central matrix with chondroid density, (c and d) T2 coronal and axial magnetic resonance imaging demonstrating the T2 hyperintense and T1 hypointense lesion involving the greater wing of the sphenoid, lateral orbital wall, and orbital roof. Faint dural enhancement of the left anterior cranial fossa overlying the mass was also noted.

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Operative biopsy through an infrabrow approach was done in conjunction with functional endoscopic sinus surgery. With respect to the biopsy, dissection was carried along the periosteum of the superior-lateral orbital rim until the lesion was encountered approximately 1.5 cm posterior to the superior orbital rim. The lesion was soft and friable compared to the surrounding bone. Specimen was sent for pathology. Frozen specimens were reported to be positive for low-grade spindle cell neoplasm. Permanent pathology later revealed intraosseous myxoma [Figure 2].

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Figure 2:: H and E stained sections of the biopsied lesion. (a) Histopathologic analysis of biopsy specimens revealed a hypocellular tumor composed of spindle, stellate, and polyhedral cells within a myxoid stroma, (b) Low-power image reveals reactive woven bone within the myxoma. Immunohistochemistry was positive for vimentin and CD68 and negative for BER-EP4, SMA, S100, MSA, CAM-5.2, PAN-CK, CD34, CD138, and CD1A. These findings were consistent with intraosseous myxoma.

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He received definite resection through the left orbitozygomatic craniotomy and gross total resection was achieved. Tumor was densely adherent to periorbita and dura; involved tissue was resected. Reconstruction of orbital roof and lateral orbital wall was done through frontal bone autograft and titanium plating.

The patient recovered well. No residual bony lesions have been identified on postoperative imaging [Figure 3].

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Figure 3:: (a) Axial and (b) coronal cuts of postoperative computed tomography head without contrast following resection of the left superior orbital rim and lateral orbital wall bony mass lesion show no residual bony lesion. Expected small area of the left frontal and soft-tissue extra-axial gas is also noted on sagittal view.

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RESULTS AND DISCUSSION

Myxomas are uncommon, benign, mesenchymal neoplasms that usually arise from soft tissues, most commonly from the left atrium of the heart.[11] They are rarely seen in the bones of the head-and-neck region, usually occurring in the mandible and less commonly in the maxilla.[4] Myxomas of the maxillary sinus can secondarily invade the orbit and skull base, as illustrated in this case. To the best of our knowledge, there have only been 29 previously reported cases of myxoma of the orbit.[2,5-8,10,13,15-19,21,23-25,27-29,31]

Typically slow-growing, painless masses, these tumors may become quite large before detection, typically presenting with slowly progressive painless proptosis. Our patient did not present with proptosis, instead, the mass was only discovered during the work-up of chronic sinusitis.

Radiographic characteristics of myxoma include[1,4,7] well-circumscribed lesions, soft-tissue density, bubbly, trabeculated appearance, and bony destruction with cortical thinning and/or dehiscence [Figure 1a]. Imaging is most beneficial for initial evaluation and preoperative planning, rather than diagnosis.

Definitive diagnosis depends on histopathology and is pivotal to eliminate the possibility of a sarcomatous component. Many reactive and neoplastic processes may show prominent myxoid degeneration and must be separated from the benign myxoma.[3] Microscopically, true myxomas appear as stellate or spindle-shaped cells with small, pyknotic nuclei.[26] Surrounding the cells is a loose myxoid or mucoid stroma rich in hyaluronidase, through which delicate reticulin fibers run.[26] In contrast, sarcomas undergoing myxoid degeneration display areas of increased cellularity, pleomorphism, mitotic activity, and a rich vascular network.[22] Myxomas stain positively for vimentin as well as partial positivity for S-100 and muscle-specific actin.[14,20]

Wide local excision with safety margins is the recommended treatment for both primary and recurrent cases due to the radioresistant and locally invasive nature of myxomas.[7,9,12,30]

Regardless of location, complete resection is indicated, as recurrence rates are high with conservative surgical management. Myxomas of the head and neck have recurrence rates as high as 28% with conservative surgical interventions, including enucleation and curettage, in contrast to 6% for local or wide excision.[1]

CONCLUSION

Our case presented above illustrates a unique surgical challenge given its proximity to both the orbit and middle cranial fossa. A multidisciplinary approach with otolaryngology and plastic surgery was utilized to achieve complete resection and reconstruction with desired outcome.