Non-hyperinsulinemic hypoglycemia in a patient with a gastrointestinal stromal tumor

Primary Functioning Neuroendocrine Tumor of the Appendix with Hypoglycemia Syndrome: A Case Report and Review of Neuroendocrine Tumors

INTRODUCTION

Primary neuroendocrine tumors (NETs) of the appendix are uncommon, but when present are usually not hyperfunctioning. This case represents an extraordinarily rare primary hyperfunctioning NET of the appendix with a clinical presentation of symptomatic hypoglycemia in an otherwise healthy man.

CASE PRESENTATION

A previously healthy 34-year-old man was found to be symptomatically hypoglycemic in early 2018. After the workup, the apparent explanation was a tumor in his midappendix, for which he was referred to our surgical oncology service for resection. The patient's clinical course is described in detail, including imaging, as well as surgical and pathologic descriptions of the appendiceal NET.

DISCUSSION

A literature review demonstrates no other case series or reports of a primary hyperfunctioning NET of the appendix presenting with hypoglycemic crisis. The symptoms of tumor-induced hypoglycemia more typically arise with islet cell tumors, such as pancreatic NETs or insulinomas. We believe this case represents a nonislet cell tumor-induced hypoglycemia. This patient's elevated serum proinsulin level preoperatively implies secretion of proinsulin by the tumor. However, tumor-induced hypoglycemia caused by proinsulin has been described previously only in pancreatic tumors. This unique case adds knowledge to the possible glycemic endocrine effects of nonpancreatic NETs, specifically those that arise primarily in the appendix.

Late Onset of Non-islet Cell Tumor Hypoglycemia Managed via Multidisciplinary Treatment in a Patient with a Solitary Fibrous Tumor

Solitary fibrous tumor (SFT) is a rare subtype of soft tissue sarcoma (STS). We herein describe a case of late onset of non-islet cell tumor hypoglycemia (NICTH) that was managed via multidisciplinary treatment in a patient with SFT. A 67-year-old man previously diagnosed with SFT 4 years prior to this presentation and treated with several rounds of surgery, presented with massive tumors. Eighteen months following his prescribed chemotherapy, the patient developed hypoglycemia. He was diagnosed with NICTH, after confirming the presence of high molecular weight insulin-like growth factor-2. This case suggests that paraneoplastic syndrome can occur even in cases of rare cancers, such as STS.

Hypoglycaemia in a 63-year-old female with a large, recurrent, metastatic gastrointestinal stromal tumour (GIST)

INTRODUCTION

Non-islet cell tumour-induced hypoglycaemia (NICTH) is rare, with few cases reported in patients with gastrointestinal stromal tumour (GIST).

CASE REPORT

A 63-year-old Chinese female with known metastatic GIST presents with persistent hypoglycaemia. Investigations revealed a likely diagnosis of NICTH, and she underwent debulking surgery. There was complete resolution of her hypoglycaemia post-operatively

DISCUSSION

NICTH should be considered in patients with GIST and hypoglycaemia. Surgical debulking is recommended as part of the management of NICTH.

Insulin-like growth factors and insulin-like growth factor-binding proteins in relation to disease status and incidence of hypoglycaemia in patients with a gastrointestinal stromal tumour

OBJECTIVE

Patients with a gastrointestinal stromal tumour (GIST) suffering from non-islet cell tumour-induced hypoglycaemia (NICTH), being associated with increased plasma levels of pro-insulin-like growth factor (IGF)-IIE[68-88], have been reported occasionally. We studied the clinical relevance of pro-IGF-IIE[68-88] and other IGF-related proteins in GIST patients.

PATIENTS AND METHODS

Twenty-four patients were included. Plasma samples were collected before 1 week and median 5 months after start of treatment with imatinib, and levels of IGF-I, total IGF-II, pro-IGF-IIE[68-88], insulin-like growth factor-binding protein (IGFBP)-2, -3 and -6 were determined. GIST specimens from 17 patients and tumour cyst fluid from two patients were analysed for IGF-II and IGFBP-2.

RESULTS

Before treatment and/or during follow-up, 3 of 24 (13%) patients showed increased plasma levels of pro-IGF-IIE[68-88]. All three developed NICTH. Overall, patients with metastatic disease, elevated serum lactate dehydrogenase activity or total tumour size >12 cm had the highest pro-IGF-IIE[68-88] levels. Most patients had increased plasma IGFBP-2 levels and these levels were significantly higher in patients with progressive disease. (Pro-)IGF-II was expressed in 82% of GISTs and IGFBP-2 only in one case.

CONCLUSION

We identified pro-IGF-IIE[68-88] as a marker that may be used in the surveillance of GIST.

Insulin-like growth factor (IGF) 1 and 2 help to predict disease outcome in GIST patients

BACKGROUND

The expression of the insulin-like growth factor (IGF) system has never been studied in gastrointestinal stromal tumors (GISTs).

PATIENTS AND METHODS

We studied the immunohistochemical expression of IGF1 receptor (IGFR-I), IGF1 and IGF2 in 94 samples of GISTs. IGF1 and IGF2 expression was scored in three classes: negative (N), moderate (M) and strong (S), according to staining intensity and extent.

RESULTS

IGFR-I was overexpressed in all cases. IGF1 and IGF2 expression was absent in 25 and 48 cases, moderate in 29 and 16 cases and strong in 40 and 30 cases, respectively. Strong IGF1 expression significantly correlated with higher mitotic index (P = 0.0001), larger (P = 0.01), higher risk (P = 0.0002), metastatic (P = 0.0001) and relapsed (P = 0.04) GISTs. Strong IGF2 expression correlated with higher mitotic index (P = 0.05) and higher risk GISTs (P = 0.001). The Kaplan-Meier analysis (N versus M versus S) showed a significant worsening of the disease-free survival (DFS) with the increase of IGF1 (P = 0.02) and IGF2 (P = 0.02) expression. In the subgroup of patients with operated high-risk GISTs, there was a better trend in DFS for patients affected by GISTs with negative IGF1 and IGF2.

CONCLUSIONS

The expression of IGF1 and IGF2 seems to predict relapse in GIST patients.