Acute lymphoblastic leukemia with large molecular ACTH production.

Ectopic hormone production is very rare in hematological malignancy. Here, we describe an interesting case of acute lymphoblastic leukemia (ALL) with adrenocorticotropic hormone (ACTH) production. A 47-year-old man was admitted to our hospital with a 7-month history of hyperpigmentation. The plasma level of ACTH was markedly elevated without a circadian rhythm and the level of cortisol was normal. Examination of bone marrow aspiration revealed ALL, and no other disease as a cause of the elevated ACTH was detected. Sephadex G-75 chromatography of plasma ACTH extract revealed the existence of an abnormally large molecular ACTH (probably proopiomelanocortin) in addition to authentic 1-39 ACTH. Ectopic ACTH of low biological activity is considered to be the reason for a discrepancy in the plasma levels of ACTH and cortisol. Shortly after remission induction chemotherapy, blast cells in the peripheral blood disappeared, and the plasma level of ACTH became normal, leading to an improvement of skin pigmentation. These clinical findings and laboratory data suggested that leukemia cells in this case may produce the ACTH.