Diplopia and extreme hyperamylasemia (>100,000 U/L) heralding aggressive IgG kappa myeloma: A case report and literature review.

RATIONALE: While the production of amylase by epithelial tumors has been well-documented, its association with multiple myeloma (MM) is exceedingly rare, with only a limited number of cases reported. Moreover, to our knowledge, the presentation of binocular diplopia as a prominent and primary clinical feature in patients with MM and concurrent hyperamylasemia has not been widely reported. PATIENT CONCERNS: This case report describes a 75-year-old man with immunoglobulin G kappa MM presenting with diplopia and extreme hyperamylasemia (>100,000 U/L) with normal lipase levels, a combination suggesting aggressive disease with extramedullary involvement. DIAGNOSES: Immunoglobulin G kappa-type MM and multiple organ dysfunction syndrome. INTERVENTIONS: The patient received the first cycle of the VD regimen, consisting of bortezomib (2.2 mg, intravenous infusion, once weekly) and dexamethasone (10 mg, intravenous drip, days 1 and 2). OUTCOMES: Despite aggressive treatment, the patient's condition deteriorated rapidly and ultimately succumbed to the disease in the early morning of the fourth week post-diagnosis. LESSONS: Patients with amylase-producing myeloma exhibit larger tumor burdens, more extensive extramedullary dissemination, and significantly shorter survival than typical MM cases. Binocular diplopia may indicate skull base extramedullary involvement. Unexplained hyperamylasemia with normal lipase should prompt malignancy screening. Early diagnosis is crucial given the rapidly fatal course.