Title:Syndrome of Inappropriate Antidiuresis and Diabetes Insipidus as Two
Sides of the Same Coin in Hypothalamic Lymphoma: A Case Report
Volume: 23
Issue: 5
Author(s): Mormando Marilda, Lauretta Rosa, Telera Stefano, Bianchini Marta, Chiefari Alfonsina, Natalino Fiammetta, Puliani Giulia and Appetecchia Marialuisa*
Affiliation:
- Oncological Endocrinology Unit, IRCCS Regina Elena National Cancer Institute, Rome, Italy
Keywords:
Lymphoma, hypothalamic neoplasms, diabetes, insipidus, inappropriate ADH syndrome, electrolytes.
Abstract:
Background: Hypothalamic-pituitary region lymphoma is rare and diabetes
insipidus (DI) represents one of the most common endocrine manifestations. We report the
first case of hypothalamic lymphoma associated with both the syndrome of inappropriate
antidiuresis (SIAD) and DI.
Case Presentation: A 64-year-old woman with a history of stage IV large B-cell non-Hodgkin
lymphoma, underwent atypical right lung resection for pulmonary nodules. A few days
after surgery, the patient presented severe normovolemic hyponatremia and serum
hypo-osmolarity, therefore, we suspected a paraneoplastic syndrome (SIAD) related to the
lung neoplasm, histologically diagnosed as typical carcinoid. The brain magnetic resonance
imaging (MRI) showed a 9 mm lesion in the hypothalamic region that significantly
increased one month later with the onset of neurological symptoms. A trans-sphenoidal biopsy
showed localization of the large B-cell lymphoma. After surgery, the patient presented
with polyuria and polydipsia, so desmopressin therapy was started. In the following days,
serum osmolarity and sodium fluctuated between normal and low values, then DI was excluded,
and SIAD became more likely. Desmopressin therapy was discontinued and
hyponatremia was treated with sodium infusion. Hypothalamic lymphoma was treated with
chemotherapy and radiotherapy with substantial shrinkage. The hyponatremia persisted
during anticancer treatments and improved only after radiotherapy, confirming
paraneoplastic SIAD.
Conclusion: Lymphomas of the hypothalamic region can cause electrolyte imbalance for
various causes. The differential diagnosis between SIAD, DI and impaired thirst centers may
not be straightforward and the electrolyte disorders must be evaluated step by step in all
different stages of the disease.
