A small intestine neuroendocrine carcinoma (SI-NEC) metastasized to the temporomandibular joint (TMJ) in a man. The case report, which is believed the first reported case of its kind, was published on March 11 in the Journal of the American Dental Association.
This case shines a light on how vital it is to consider metastasis in the differential diagnosis of TMJ pain in patients with neuroendocrine carcinoma, the authors wrote.
"To our knowledge, this is the first documented case of SI-NEC metastasizing to the condyle, highlighting the diagnostic and management challenges of a multifactorial orofacial condition," wrote the authors, led by Dr. Shaiba Sandhu, MS, of the Workman School of Dental Medicine at High Point University in North Carolina.
A 60-year-old man with chronic jaw pain
The man reported a dull to intense ache localized to the left TMJ and left ear for about 18 months. The pain, which was intermittent, was mostly aggravated when he was lying on the left side of his face.
The man had no history of typical TMJ symptoms, like jaw locking or clicking, teeth grinding, or head or neck trauma. He was undergoing chemotherapy for metastatic neuroendocrine carcinomas (NECs) and receiving antiresorptive therapy infusions with denosumab for bone metastases and hormone therapy as part of his treatment for the past nine years.
The patient underwent an exam that revealed no facial swelling or asymmetry, but his left TMJ and deep masseter were tender upon touch. Other function tests were normal.
However, a panoramic x-ray revealed a poorly defined reduction in density, with evident destruction of the anterior cortical boundary of the left condyle and condylar neck. Also, a generalized increase in density along the posterior aspect of the left condyle was seen adjacent to the poorly defined reduction.
Computed tomography (CT) showed eradication of the lateral aspect of the patient's left condyle, as well as an increase in density within the medial aspect of the condyle. In multiple axial sections, there was periosteal new bone formation along the lateral aspect of the man's condylar neck. Adjacent to the condyle, there were multiple, tiny, well-defined radiopacities within the soft tissue component, the authors wrote.
The asymptomatically exposed bone on the lingual aspect of the left jaw was diagnosed as stage I medication-related osteonecrosis of the jaw related to the man taking antiresorptive therapy with denosumab.
Based on the imaging, clinicians gave differential diagnoses for the patient's entity within his left TMJ area, including a primary TMJ tumor, such as osteosarcoma, metastatic NEC, or an aggressive-appearing benign inflammatory condition, they wrote.
However, a positron emission tomography (PET)-CT study showed a localized area of heightened radionuclide uptake. This PET-CT used the radioactive substance copper 64 dotatate to locate and visualize somatostatin receptor-positive NEC lesions. These types of tumors are overexpressed on this type of imaging. Therefore, the other diagnoses were excluded, confirming the diagnosis of metastatic SI-NEC of the man's left TMJ, the authors wrote.
To control the patient's TMJ symptoms, he was prescribed steroids, a muscle relaxant, and an antimicrobial rinse and was told to do jaw stretches. At a six-month follow-up, his TMJ symptoms were gone.
Due to widespread metastatic disease, the man continued to be treated with chemotherapy, as well as hormone and antiresorptive therapy, they wrote.
"Although the prognosis is typically poor in cases of condylar metastasis associated with widespread metastatic disease and is often indicative of advanced malignancy, our patient continues to survive," the authors wrote.
What clinicians need to know
Condylar metastases are extremely rare. They account for about 3.5% of all maxillofacial metastases, most of which stem from breast, prostate, and lung adenocarcinomas. Moreover, there have been some cases in which the cancer has spread from the condyle from the stomach, colon, liver, and pancreas, but until now, there had been no reported cases of metastases from the small intestine, they wrote.
In cases of persistent TMJ pain, swelling, or dysfunction that are unresponsive to standard therapies combined with atypical symptoms like malocclusion and sensory disturbances, clinicians should consider metastatic cancer to the TMJ.
"With the growing role of oral health care providers, including oral medicine and orofacial pain specialists, in oncology settings, it is critical for clinicians to be aware of metastatic lesions affecting the TMJ and their associated symptoms," Sandhu and colleagues wrote.
