Rare Bone Metastasis of Neuroendocrine Tumors of Unknown Origin: A Case Report and Literature Review

BACKGROUND: The neuroendocrine tumor (NET) is rare, accounting for about 0.5% of all tumors. NETs have the characteristics of metastasis, especially lymph nodes, liver, spleen, and bone. CASE PRESENTATION: We report a 30‐year‐old man diagnosed with a NET with bone metastasis and presented with waist and leg pain. The imaging findings of this case showed multiple osteosclerosis and no apparent bone destruction. We collected the patient's previous examinations, including laboratory, imaging, and pathological examination to get a precise diagnosis. Given this case, we carried out symptomatic support treatment to relieve the patients' pain symptoms. CONCLUSION: Bone metastases from NETs of unknown primary site are rare in both clinical and imaging manifestations. The disease is mainly manifested as multiple osteosclerosis, accompanied by muscle soreness and pain. It is recommended to try chemotherapy for this disorder.