A 39-year-old male patient suffered from pain in the right temporo-mandibular-joint (TMJ) region for more than one year particular when chewing. He was suspected of having a parotis gland tumor and was admitted to the ENT Department. Three months prior to admission there was an increasing swelling. MRT contrast enhanced scan proofed a partly cystic partly soft tissue dense tumor in the regions of the masseter and pterygoideus medialis muscles and the cranial parts of the parotic gland. Ultrasound scan confirmed these findings and showed in addition a suspect lymph node at level II. Electroneurography of the facial nerve was without pathology. Biopsies revealed no pathologies. With persisting pain the patient was transferred to the Department of Oral and Maxillofacial Surgery. History and clinical examination revealed: regular use of chewing gum for several years, pain and clicking in the TMJ and use of a dental splint without relief after removal of the wisdom teeth 28 and 38. Special radiographic diagnostics did not show any pathology but the swelling was persisting. Open joint surgery and histology proofed a chronic synovialitis of the TMJ. In the follow-up after 7 months the patient was free of pain and complaints. This case demonstrates the necessity of interdisciplinary collegial communication to optimally treat patients that suffer from pathologies at the borders of the specialised fields in the head and neck region.