Esophageal neuroendocrine carcinoma complicated with unexpected hyperprocalcitonin: Case report and literature review

RATIONALE: Neuroendocrine tumors (NETs) with hyperprocalcitonin are relatively rare with a low incidence rate. PATIENT CONCERNS: An afebrile 63-year-old male with persistent low back pain unexpectedly presented with an extreme hyperprocalcitonin. Radiological assessment revealed thickening of the esophageal wall with vertebral bone destruction and liver lesions. Endoscopy showed an irregular-shaped esophageal lesion which turned out to be poorly-differentiated NETs. DIAGNOSIS: Esophageal NETs with multiple metastases. INTERVENTIONS: The patient was treated with chemotherapies, and was evaluated by procalcitonin level and radiology within follow-up. OUTCOME: The procalcitonin levels were altered in line with the therapeutic response and disease progression during the treatment course. LESSONS: Increased procalcitonin occurs in several malignancies with neuroendocrine components, such as NETs of the digestive system.