G.Z. Mukhametshina1, 2, Z.A. Afanasyeva1, 2, I.I. Galiev1
1Kazan State Medical Academy — branch campus of the FSBEI FPE RMACPE MOH Russia, Kazan
2Republican Clinical Oncology Dispensary named after Professor M.Z. Sigal, Kazan
Galiev I.I. — 2nd-year resident of the Department of Oncology, Radiology and Palliative Medicine
11 Mushtari St., 420012 Kazan, e-mail: i1naz_16@mail.ru, ORCID ID: 0000-0001-7858-5238
Abstract. Small-cell neuroendocrine carcinoma of the esophagus (SCCE) is a rare and highly aggressive subtype of gastrointestinal neuroendocrine neoplasms (NENs), accounting for less than 1% of all malignant esophageal tumors. The disease is characterized by rapid symptom progression, early metastasis, and an unfavorable prognosis comparable to that of small-cell lung cancer. Paraneoplastic syndromes typical of neuroendocrine neoplasms may predominate over local symptoms, necessitating their correction to prevent severe complications. According to the literature data, hyponatremia is a common electrolyte disorder in oncology patients and may substantially complicate the clinical course, worsen prognosis, and reduce treatment tolerability. One of the key mechanisms of hyponatremia in oncology is the syndrome of inappropriate antidiuretic hormone secretion (SIADH), which is frequently observed in small-cell carcinomas. We present a clinical case of a patient with small-cell neuroendocrine carcinoma of the esophagus complicated by SIADH.
Key words: neuroendocrine carcinoma; small-cell neuroendocrine carcinoma of the esophagus; SCCE; syndrome of inappropriate antidiuretic hormone secretion; SIADH; hyponatremia; paraneoplastic syndrome