Endocrine Abstracts

A 52-year-old male patient with no past medical history of interest was admitted to our Endocrinology Unit with a clinical course developed in the last month of sudden polyuria, nocturia and polydipsia (8 liters/day) associated with bilateral low back and leg pain, a right-side nasal congestion with eye swelling and paresthesia. Physical examination revealed a doubtful thickening of the nasal mucosa and several two-cm- scattered erythematous disseminated skin lesions. Blood samples showed basal sodium levels between 146-148 mEq/dl. A Miller test confirmed the diagnosis of Central Diabetes Insipidus (CDI) with a urine osmolality of 444 mOsm/kg that raised to 720 mOsm/kg after desmopressin. Anterior pituitary hormone levels were within normal range. A pituitary MRI showed a focal 10x7x10 mm posterior lesion with extension towards to the pituitary stalk, along with bilateral mucous thickening in ethmoid cells and occupation of nostrils, especially in the right side. During admission, the patient presented worsening of nasal symptoms, solid and liquid dysphagia and advance of skin lesions, which were biopsied. Oral desmopressin was started at a dose of 90 mg/day and subsequently moved on to 240 mgc/day due to persistent polyuria. Infectious processes, germinoma, autoimmune and associated granulomatous disease were ruled out. Due to symptomatology and imaging tests, a diagnostic lumbar puncture was performed, showing infiltration of 66% NK cells by flow cytometry in CSF. Similar findings were observed in skin biopsy with cutaneous infiltration by T cells with CD3 epsilon, CD 7, CD56, granzyme and perforin positive immunophenotype, positive ISH EBER and ki-67 > 90 %. An 18-FDG-glucose- PET-TC showed extensive supra and infradiaphragmatic nodal invasion with splenic, pituitary, nasosinusal, spinal cord and lumbosacral root cord and probable hepatic, adrenal, cutaneous and bone involvement. According to Pink Scale a diagnosis of high score extranodal T/NK lymphoma, nasal type stage IV with cutaneous and central nervous involvement was stated. The patient started a chemotherapy treatment (SMILE protocol) that included dexamethasone, methotrexate, ifosfamide, l.asparaginase and etoposide with clinical improvement and radiological resolution of brain lesions three months afte the diagnosis.

Conclusion: The diagnosis of central DI always makes it necessary to rule out infectious, autoimmune, infiltrative and hematological diseases. Extranodal NK/T lymphoma (nasal type) is a rare neoplasm with an aggressive behavior, first reported here in presenting with CDI, in which early diagnosis and treatment is essential.