Metastatic neuroendocrine carcinoma of the small intestine presenting as temporomandibular disorder.

Background: Neuroendocrine carcinomas (NECs) are rare tumors from hormone-secreting neuroendocrine cells, often within the gastrointestinal tract. The authors report what is, to their best knowledge, the first case of a small intestine NEC metastasizing to the temporomandibular joint (TMJ).

Case description: A 60-year-old man came to the oral medicine, oncology, and orofacial pain clinic with a chief concern of left-sided jaw pain. Clinical examination revealed left TMJ arthralgia and deep masseter myalgia, and results of imaging showed both osteoblastic and osteolytic changes in the left TMJ. A comprehensive diagnostic approach, including detailed history, clinical evaluation, and advanced imaging techniques, such as positron emission tomography computed tomography, was used to establish an accurate diagnosis.

Practical implications: This case highlights the importance of considering metastasis in differential diagnosis of TMJ pain in patients with NEC, underscoring collaboration between oncology and orofacial pain specialists for accurate diagnosis and effective management.