Adenoid cystic carcinoma of the orbit with bilateral cavernous sinus extension: A case report

INTRODUCTION AND IMPORTANCE: Adenoid cystic carcinoma (ACC) is an uncommon malignant epithelial tumor of the salivary and lacrimal glands. Orbital ACC is rare, originating commonly from the lacrimal gland, with only a few cases reported without lacrimal gland involvement. Deep orbital ACC may be associated with extension into skull base structures, and further intracranial invasion. CASE PRESENTATION: We report a 47-year-old gentleman who presented with insidious onset of bilateral proptosis, left ophthalmoplegia, and loss of vision. Imaging revealed left orbital infiltrative mass with intracranial invasion and bilateral cavernous sinus extension. The lacrimal gland was not involved clinically nor radiologically. Histopathology showed ACC with classical cribriform pattern. There was no evidence of primary source of tumor or metastasis. DISCUSSION: ACC of the orbit commonly originates from the lacrimal gland. Only a few cases of orbital ACC without lacrimal gland involvement were found in English literature. Workup for our patient did not reveal a primary source of tumor. Tumor may have risen from ectopic orbital lacrimal gland tissue, extension from non-orbital sites, or through perineural or hematogenous spread. Only one case of bilateral cavernous sinus extension has been previously reported. Treatment for advanced orbital ACC is exenteration in most cases. However, due to the advanced nature of disease in our patient, palliative radiotherapy was the treatment of choice. CONCLUSION: Orbital ACC of non-lacrimal origin is rare and is associated with high morbidity and mortality. Early recognition and treatment are key for preventing organ and life-threatening complications such as advanced intracranial spread.