PURPOSE: To report a case of Cushings syndome caused by ectopic ACTH secretion related to a thymic carcinoid presented with trombositopenia.
CASE: years old male presented with fatigue, skin rash. At presentation, physical findings showed Cushingoid appearance, with moon face, hyperpigmentation, easy bruising and buffalo hump. His laboratory findings showed platelet: 90.000 (150.000450.000), ACTH: 609 pg/ml (046 pg/ml), baseline cortisol level 60.8 μgr/dl (6.219 μgr/dl), potassium: 2.4 mEq/l (3.55 mEq/l), midnight cortisol level: 57.17 μgr/dl, urine cortisol level: >1000 μgr/24 hour. Serum cortisol levels failed to supress after low and high dose dexamethasone (DST) (1 mg: >60 μgr/dl, 8 mg: 42 μgr/dl), therefore confirming the diagnosis of ectopic ACTH production. Laboratory evaluation for trombositopenia showed, normal eritrocyte series, deficient trombocyte. PT, aPTT and FDP were normal, fibrinojen: 606 mg/dl (<350). Megacaryocyte level was elevated and platelet count was normal in bone marrow aspiration. His sella MRI was normal, thorax CT showed 2×1.5 cm lesion at anterior mediastinum, and surrenal hyperplasia on his abdomen CT. His octreoscan was normal. There was a hypermetabolic focus in anterior mediastinum and bilaterally adrenal gland on his 5FDG PET/CT. Under the diagnosis of ectopic ACTH production in anterior mediasten, he underwent mediastinotomy and thymectomy. Pathological examination showed ACTH, chromogranin and synaptophsin positive thymic benign carcinoid. After the operation his cortisol levels returned to normal (corisol:11 μgr/dl, ACTH: 54 pg/ml) and low dose DST was 1.6 μgr/dl. Three weeks after the operation his platelet count was 411.000, with exclusions of other causes of tromposytopenia and reversal of platelet counts to normal after the operation we concluded that his trombosytopenia was due to a paraneoplastic immune trombocytopenic purpura (ITP).
CONCLUSION: Thymic ACTH secreting carcinoid tumors are rare phenomenon of ectopic Cushings syndome. To our knowledge this is the first case of ectopic Cushings disease with paraneoplastic ITP.