Cushing's syndrome as presentation of an ACTH-producing pulmonary tumour
Pedro Rodrigues1, José Luís Castedo1, Eduardo Cernadas2, Davide Carvalho1 & José Luís Medina1
Introduction: Ectopic Cushings syndrome is a rare disease, with a reported incidence of 0.1/million per year. This disorder accounts for approximately 1217% of patients with ACTH-dependent Cushings syndrome. Small cell lung carcinoma is responsible for about 20% of cases, although ectopic ACTH hypersecretion occurs in only 0.52% of these tumours. Hypercortisolaemia is usually severe and of rapid onset. Optimal treatment is surgical excision of the tumour, although not always possible. Prognosis is poor in most cases, with a short mean survival.
Case report: We report a 52-year-old male patient admitted to the hospital in 1993 with a 6-month history of hypertension and temporal headaches. He presented plethoric facies, central obesity and wide and red skin striae. Laboratory assays showed high plasma ACTH and markedly elevated urinary cortisol excretion that was not suppressed with high dose dexamethasone administration. Pituitary MRI and adrenal glands CT scans were normal. No central-peripheral ACTH gradient was observed in the bilateral inferior petrosal sinus catheterism. Thoracic CT scan showed a 1.7 cm nodule in the superior lobe of the left lung. Pulmonary fine needle citology and immunocytochemical and ultrastructural studies led to the diagnosis of an ACTH-producing neuroendocrine carcinoma. He was initially submitted to chemotherapy and, in 1995, started octreotide, presenting a favorable clinical response. Last octreotide scintigraphy (May 2009) showed persistence of a small enhanced nodule in the left pulmonary parenchyma. He is on treatment with octreotide LAR (long acting release) having the disease clinically controlled.
Discussion: We highlight the ectopic ACTH secretion as a rare feature of neuroendocrine lung carcinoma and its favorable evolution, 16 years after it was diagnosed.