Introduction:Representing approximately 30-40% of all non-Hodgkin lymphoma, the diffuse large B-Cell lymphoma (DLBCL) is the most common subtype of malignant lymphoma. It typically arises from nodal origin but an affection of any organ or tissue could in principle be possible. Approximately one third of all DLBCL is of extra-nodal origin. Most commonly, they are found in the gastrointestinal or genitourinary tract, skin and soft tissues or bone, while a primary tumor arising from paranasal sinus and nasal cavity is rare. Because of its rarity, early-stage symptoms for malignant lymphoma of the paranasal sinus are insufficiently described in the existing literature. Therefore, an early diagnose still remains challenging.

Material: In this report, we present the case of a 89 year old male patient with sudden onset of diplopia and vision disturbance of the left eye as well as left frontal and orbital pain. The CT scan showed a tumor mass of the left frontal sinus with invasion of the naso-orbitoethmoid region.

Results: The biopsy was taken and the specimen diagnosed for a DLBCL. The Patient was then referred to the oncology department for combination chemotherapy.

Discussion: By describing the clinical presentation of DLCBL of the frontal sinus and its diagnostic process, we aim to increase physician awareness and familiarity with this rare pathology.

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