We describe a patient with Doege-Potter syndrome (solitary fibrous tumor of the 
pleura presenting with hypoglycemia) and illustrate several important lessons 
learned from the case. Seven years after the initial diagnosis, the tumor showed 
significant growth and developed a high-grade undifferentiated component. 
Solitary fibrous tumors do grow and cannot be deemed benign. Resection should be 
considered in all patients who are candidates for operation upon diagnosis. Our 
case also serves as a reminder of this rare syndrome, inasmuch as early 
recognition of the association of hypoglycemia with these tumors may have 
allowed for earlier diagnosis and avoidance of extensive tests in our patient.