Multicentric Castleman disease with trismus

A 58-year-old man visited our hospital with trismus and anorexia in the past 1 month (Fig. 1A, B). Multicentric Castleman disease was suspected due to cervical and axillary lymphadenopathy on CT, a high inflammatory response and IL-6 level elevation. Lymph node biopsy revealed mantle zone development, interfollicular expansion, extensive plasma cell infiltration and cluster of differentiation 3-positive (CD3+) T cell accumulation, leading to the diagnosis of plasmacytic Castleman disease. CT findings could not explain the cause of trismus (Fig. 1C). PET-CT revealed increased fluorodeoxyglucose uptake in the right temporomandibular joint, implicating temporomandibular joint arthritis as the cause of trismus (Fig. 1D, arrow). Trismus rapidly improved after prednisolone and IL-6 inhibitor administration. Similar to RA, Castleman disease is a lymphoproliferative disease with IL-6–related systemic inflammation. Temporomandibular joint arthritis is an articular symptom of RA, but arthritis in Castleman disease has rarely been reported. Activation of CD3+ cells by IL-6 is a potential mechanism of arthritis [1]. CD3+ T cells were clearly observed in the lymph nodes in our patient, which indicates arthritis. We report a case of trismus associated with temporomandibular arthritis, which we consider to be highly representative of the pathophysiology of Castleman disease.