Lymphomas are indeed complex malignancies with diverse clinical and pathological characteristics. Non-Hodgkin's lymphoma (NHL) is particularly notable for its varying presentations, with a significant number of cases manifesting as lymphadenopathy. The extranodal involvement in about one-third of NHL cases highlights the importance of recognizing atypical presentations. In this case, we present a 59-year-old male patient with non-Hodgkin lymphoma in the right buccal mucosa.

A 59-year-old male patient with a history of allergic asthma and gastroesophageal reflux disease presented to our clinic with swelling in the right maxillary region lasting more than one year. The patient did not have any B symptoms. A biopsy of the right buccal mucosa revealed extranodal marginal zone non-Hodgkin lymphoma. Immunohistochemistry showed: CD20(+), CD43(+), CD38 positive in plasma cells, diffuse BCL2(+), suboptimal BCL6(+), and a proliferation index of 5% reported with Ki67. An MRI of the orbit demonstrated a mass lesion extending from the right maxillary region into the temporal fossa, with partial external protrusion from the right cheek. After intravenous contrast administration, diffuse enhancement was observed in the right lateral wall of the sphenoid sinus, which was in close proximity to the right cavernous sinus and caused contrast retention at these levels, extending into the subcutaneous adipose tissue of the right temporal region. The right globe appeared exophthalmic. Simultaneous laboratory parameters were normal, with a beta-2 microglobulin level of 1.65 mg/L and LDH of 180 U/L. An F-18 PET-CT scan showed irregular soft tissue densities in the right maxillary region exhibiting hypermetabolism (primary disease). Several lymph nodes in the right cervical chain showed relative hypermetabolism (possible metastasis). The treatment plan was decided upon in consultation with the ear, nose, and throat and neurosurgery departments regarding potential involvement of the central nervous system.

Non-Hodgkin's lymphomas comprise a varied group of malignancies that primarily affect lymph nodes. Extranodal NHL represents approximately 20-30% of all reported cases. Among the extranodal sites, the head and neck region is the second most frequently involved area, after the gastrointestinal tract. Intraoral non-Hodgkin lymphoma accounts for only 0.1% to 5% of all cases.

In summary, our case emphasizes the importance of considering lymphomas in the differential diagnosis of rare malignant lesions in the oral cavity. It is believed that prompt referral for histopathological and immunohistochemical examinations can facilitate early diagnosis and appropriate treatment.