Very late recurrence of B-cell acute lymphoblastic leukemia masquerading as a pituitary tumor.

Involvement of the pituitary gland by leukemic infiltration is exceedingly rare. Here, we describe a very late recurrence of B-cell acute lymphoblastic leukemia masquerading as a pituitary tumor and review the literature for previously reported cases. Our female patient presented 13 years after completion of therapy for B-ALL with headache, amenorrhea, galactorrhea and a pituitary mass. Subsequent studies revealed recurrence of her leukemia, and the pituitary lesion resolved after induction chemotherapy. Our case highlights the importance of considering leukemic infiltrate in the differential diagnosis of pituitary mass, particularly in a patient with a history of hematologic malignancy, sparing unnecessary surgical intervention and informing endocrine evaluation. In addition, the case also highlights difficulties with characterizing this recurrence as a very late relapse or clonal evolution of the original leukemia.