Non-Hodgkin Lymphoma of the External Auditory Canal: A Rare Primary Involvement.

The authors describe a rare case of non-Hodgkin lymphoma (NHL) with primary involvement of the external auditory canal (EAC) and subsequent dissemination to the central nervous system, initially manifesting as a benign ear infection. This case highlights the importance of considering differential diagnoses in patients with persistent or worsening symptoms unresponsive to empirical treatment. A 53-year-old man presented with a one-week history of aural fullness, otalgia, and otorrhea in the left ear. The first examination of the EAC showed no masses or lesions, but the tympanic membrane was bulging and erythematous. A diagnosis of acute otitis media was established, and the patient started empirical antibiotic treatment. However, the patient's symptoms worsened during the course of therapy. A brain MRI revealed a lesion occupying the left EAC, extending to the retro-auricular region, surrounding the mastoid. The patient underwent an excisional biopsy of a postauricular lesion, and histological examination was compatible with diffuse large B-cell lymphoma. Chemotherapy was initiated, but at the end of the treatment, the disease progressed. The patient subsequently underwent second-line chemotherapy and was referred for a transplant consultation. In this case, the NHL of the EAC initially presented as an apparently benign ear infection, masking the underlying severity of the disease. In summary, NHL presents a significant challenge, not only because of their heterogeneous and non-specific clinical presentation which can delay diagnosis but also because of the difficulty in treatment. This report emphasizes the need for high clinical suspicion and a comprehensive diagnostic approach to improve the prognosis of patients with NHL in atypical locations.