Oral cavity malignant lymphomas are exceptionally rare, highly aggressive, and most commonly a sign of relapse—a 10-year retrospective analysis in a single institution

Background Malignant non-Hodgkin lymphoma (NHL) represents approximately 5% of all malignancies of the head and neck region and is the third most common after squamous cell carcinoma (SCC) and salivary gland tumors. NHL originates from the B or T cells of lymphatic tissue. Only 24% of NHL affect extranodal locations. The head and neck region is the second most common site of extranodal manifestation. Only 0.1% to 5% present in the oral cavity, of which the majority are diffuse large B-cell lymphomas (DLBCLs). Intraoral cases manifestations appear as part of progressive or recurrent disease after treatment failure. Primary NHLs in the oral cavity are exceptionally rare. In our study, we conducted a retrospective clinicopathologic analysis of all cases of intraoral soft tissue malignant lymphomas. Case Summary Between 2008 and 2018, there were 11 cases of intraoral soft tissue NHLs, including extremely rare cases, such as natural killer/T-cell palatal lymphoma, mantle cell lymphoma, Burkitt lymphoma that transformed into DLBCL, and mycosis fungoides (cutaneous T-cell lymphoma) of the tongue. All patients were negative for human immunodeficiency virus infection. Age range was 14 to 77 years. The presentation of lesions was diverse, ranging from swellings mimicking dental abscesses to deep ulcers mimicking SCCs and even deep fungal infections. Thus, a fast and accurate differential diagnosis was of high importance. In some of the patients, the oral cavity was the primary site of the disease, which, in part, was a sign of relapse or part of disseminated illness. The most common location was the hard palate. In greater than 90% of cases, intraoral lymphoma was the first sign of relapse. Of these patients, 55% died within 6 months of the oral manifestation of NHL; therefore, early detection of intraoral relapses is critical and highly important. Conclusions Oral mucosal manifestation of NHL is rare and, in most cases, the first sign of relapse. Many NHLs can present in oral soft tissues, and most are fatal, so clinicians should take NHL into consideration when making their differential diagnosis. NHL lesions can mimic periodontal disease, acute abscess, or even other malignancies.