Extranodal MALT lymphoma masquerading as a cavernous hemangioma: A diagnostic and surgical challenge

Orbital extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) is a rare malignancy that typically presents as a painless, slowly growing orbital mass. It can closely mimic other benign orbital tumors, including cavernous hemangiomas, leading to diagnostic and surgical challenges. We present the case of a 69-year-old male patient with a three-week history of progressive left lateral orbital pain, mild proptosis, and diplopia on lateral gaze. MRI revealed a 1.7 cm well-circumscribed, homogenously enhancing mass in the lateral intraconal orbit, initially suggestive of a cavernous hemangioma. The patient underwent a left orbitotomy with osteotomy, during which the lesion exhibited atypical intraoperative behavior by retracting into the orbit. The excised tumor tissue was sent for histopathologic evaluation, which revealed MALT lymphoma. The patient was referred to hematology/oncology for further management. This case highlights the diagnostic challenge of distinguishing MALT lymphoma from benign orbital tumors, such as cavernous hemangiomas. MALT lymphoma typically involves the extraconal space, but this case highlights that it can present intraconally, with imaging features on MRI resembling the features of cavernous hemangioma. Advanced imaging and histopathology remain crucial for more accurate initial diagnoses and treatment planning. In conclusion, orbital MALT lymphoma can masquerade as a benign tumor, necessitating a broad differential diagnosis.