Syndrome of inappropriate antidiuretic hormone secretion due to marginal zone lymphoma: responding to rituximab

Natural killer/T-cell lymphoma with concomitant syndrome of inappropriate antidiuretic hormone secretion: A case report and review of literature

We report a case of natural killer (NK)/T-cell lymphoma with concomitant syndrome of inappropriate antidiuretic hormone secretion (SIADH). The patient was a 64-year-old woman with a history of nasopharyngeal carcinoma of over 30 years. She was admitted with a chief complaint of intermittent fever for 2 mo. Palpation after admission indicated a swollen lymph node below the left jaw. Multiple imaging examinations on admission indicated multiple enlarged lymph nodes throughout the body. We performed a left submandibular lymph node biopsy, and the results revealed NK/T-cell lymphoma. A biochemical examination indicated Epstein-Barr virus positivity. At the same time, the patient developed hyponatremia. Based on her laboratory examination and clinical manifestation, decreased plasma osmolality, urine osmolality greater than plasma osmolality, lack of skin swelling, normal blood pressure, normal renal function, no adrenal function detected on serology, and no abnormalities in imaging examination of the adrenal glands, the likelihood of SIADH in the patient was high. After fluid restriction and administration of sodium chloride, the patient’s blood sodium level gradually increased. Subsequently, the immune function of the patient declined, there were severe symptoms of infection, and she died of respiratory failure. NK/T-cell lymphoma associated with SIADH has not, to our knowledge, been previously reported in PubMed. This case emphasizes the importance of monitoring serum ion levels, especially serum sodium, in patients with NK/T-cell lymphoma.

Syndrome of Inappropriate Antidiuretic Hormone Secretion in a Patient with Mucosa-associated Lymphoid Tissue Lymphoma

Syndrome of inappropriate antidiuretic hormone secretion (SIADH) may develop in association with several malignancies. However, as an immunohistochemical analysis is not performed in the majority cases, its true cause is often uncertain. We herein report a case of SIADH following chemotherapy due to tumor-derived ADH production in a patient with mucosa-associated lymphoid tissue (MALT) lymphoma. A retrospective immunohistochemical analysis demonstrated ADH expression by lymphoma cells. These findings highlight the importance of using an immunohistochemical analysis to determine ADH production by tumor cells in patients with SIADH. Such analyses play an important role in elucidating the pathogenesis of SIADH and determining the most appropriate treatment.