Rosai-Dorfman disease in the larynx

Rosai-Dorfman disease in the larynx Dear Editor: The article “Rosai-Dorfman disease with isolated laryngeal involvement” in the October 2012 issue10 is very interesting, and we found it useful in helping us reach the diagnosis in a case of Rosai-Dorfman disease (RDD) of the larynx. Our experience with this case led us to formulate an opinion about the correct interpretation of the rarity of this localization in the larynx. Reports indicate that 43% of patients with RDD exhibit extranodal disease, with the head and neck region being one of the most common extranodal areas involved.2,3 Within the head and neck, the most common locations are the nasal cavity, paranasal sinuses, and orbit; laryngeal involvement is extremely rare, as only 16 cases have been reported in the literature.4,5 Our opinion is that localization of RDD in the larynx is rare, as indicated by a review of the literature, but it can be explained by the anatomy of the larynx itself. The larynx, despite the absence of lymph nodes, has endolymphatic tissue, which is located in the soft tissues, as part of the MALT (mucosa-associated lymphoid tissue) system. The MALT system is present in different locations of the human body, predominantly in the submucosal region, and is an important part of the immune system. In the larynx, the MALT system is prevalent in the supraglottic region and is present in each of the subsites of the larynx, as well.6 RDD is therefore localized in the intranodal and extranodal (MALT system) lymphatic system. According to the literature, RDD of the larynx is rare, but when you consider that 43% of patients with an extranodal manifestation of RDD have involvement of the MALT system, which is widely represented in the larynx, it is our opinion that the larynx should be considered as a possible location of the disease. Hence, it is not uncommon, and therefore should not be considered a rare organ disease.