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Diabetes/Prediabetes/Hypoglycemia

(9.01) A case of Doege-Potter Syndrome from an insulin growth factor (IGF)-II secreting “high risk” retroperitoneal solitary fibrous tumor

Friday, May 10, 2024
10:30 AM – 10:45 AM CDT
Location: ePoster Showcase, Empire Ballroom Foyer, Level 2

    Submitter(s)

  • Sheryl Thant Yu Htoo, MD

    Clinical Fellow
    Zucker School of Medicine/Northwell at Lenox Hill Hospital
    Hicksville, New York, United States

Introduction : Doege-Potter syndrome is a rare paraneoplastic condition characterized by non-islet-cell tumor hypoglycemia (NICTH) secondary to hyper-secretion of IGF-II.  Surgical resection has been shown to be curative for benign tumors.  However, consensus guidelines for treatment of malignant tumors are still lacking. 

Case(s) Description : A 69-year-old male with no past medical history was brought to the hospital after being found agitated and altered at home. He had been reportedly experiencing unexplained transient episodes of erratic behavior and diplopia over the past 4 to 6 months. On presentation, he was found to be markedly hypoglycemic with blood glucose 40mg/dL, undetectable serum insulin <1uU/ml, and suppressed c-peptide 0.6ng/ml (1.1-4.4).  He required continuous D10 infusion at >100ml/hr to maintain normoglycemia.  Given there was no biochemical evidence of insulinoma, no history of diabetes or gastric surgery, no clinical evidence of sepsis, renal/hepatic failure or poor oral intake, we were concerned of an extra-pancreatic process causing the sustained hypoglycemia. Therefore, CT abdomen/pelvis was obtained which showed a 13.6x10.3x12.6 cm heterogeneously enhancing retroperitoneal mass spanning from the aortic bifurcation inferiorly toward the dome of the bladder.  On MRI, the mass was partly cystic and had solid areas demonstrating avid contrast enhancement and diffusion restriction.  Our primary suspicion at this time was NICTH from the retroperitoneal mass. CT chest was negative.  Further investigations showed an IGF-II level of 952ng/ml (333-967), IGF-I of 33ng/ml (29-245) and IGF binding protein (IGFBP)-3 of 1726ug/l (1926-5487). The elevated IGF-II to IGF-I ratio of >10:1 and the suppressed IGFBP-3 level supported our working diagnosis of an IGF-II secreting neoplasm in the retroperitoneum. After additional biochemical studies indicated that the tumor was not a paraganglioma, the patient underwent midline laparotomy and en-bloc resection of the mass.  His blood glucose normalized post-operatively, IGF-II level decreased to 377ng/ml, serum insulin and c-peptide levels improved to 10.8uU/ml and 2.0ng/ml respectively. The mass was histopathologically profiled as a solitary fibrous tumor with high-risk features (mitotic rate 4/10 HPFs with evidence of necrosis), thus confirming the diagnosis of Doege-Potter syndrome.

Discussion : We present an interesting case of an elderly patient with severe hypoglycemia secondary to IGF-II secretion by a malignant retroperitoneal tumor. The initial biochemical work-up showed an undetectable insulin level at the time he was hypoglycemic, thereby ruling out an insulinoma. Abdominal imaging revealed a large retroperitoneal tumor, to which surgical resection of the tumor resulted in resolution of the hypoglycemia, with normalization of the serum insulin, c-peptide and IGF-II levels. While surgical resection has been shown to be effective for most cases of Doege-Potter syndrome, consensus guidelines for post-operative management (i.e. surveillance and possible neo-adjuvant chemotherapy) of malignant fibrous tumors with high metastatic potential are lacking.