Hypoglycemia Observed on Continuous Glucose Monitoring Associated With IGF-2-Producing Solitary Fibrous Tumor

Unraveling the Whipple Triad: Non-Islet Cell Tumor-Induced Hypoglycemia

Tumor-induced hypoglycemia (TIH) is a rare paraneoplastic phenomenon resulting from several tumor types and mechanisms. Insulinomas are the most common cause of TIH. However, non-islet cell tumors can also trigger hypoglycemia by releasing insulin-like growth factor 2 (IGF-II) or its precursor. We present a case of a 56-year-old woman experiencing spontaneous hypoglycemia due to a pleural-based solitary fibrous tumor. Diagnostic evaluations revealed diminished C-peptide levels, increased IGF-II, and a 4-fold increase in the IGF-II: IGF-I ratio, indicative of non-islet cell tumor hypoglycemia. Localization imaging identified a left pleural mass, confirming the diagnosis. Preoperatively, the patient received intravenous dextrose and corticosteroids, but surgical resection was essential for the resolution of symptoms. The identified tumor, a benign solitary fibrous tumor, was successfully removed, leading to an immediate postoperative cessation of hypoglycemia. Six years post resection, the patient remains symptom free. Managing TIH necessitates an early diagnosis aiming for complete tumor resection, with alternative approaches considered when complete resection is not possible. This case highlights the importance of a systematic diagnostic and management approach for TIH, emphasizing the need to identify the underlying cause, particularly in people without diabetes.

Primary retroperitoneal solitary fibrous tumor: A case report

Primary retroperitoneal masses have numerous differential diagnoses, many of which are rare entities. These can be neoplastic or nonneoplastic. Among the rare conditions are solitary fibrous tumors, which can either be benign or malignant. It is a mesenchymal, spindle-cell tumor, reported first in 1931 as a pleural tumor by Klemperer et al. A 20-year-old lady, with abdominal pain for 6 months, was diagnosed with a retroperitoneal mass on the left lower abdomen on USG which was confirmed by an MRI scan of the abdomen. The patient underwent laparoscopy-assisted excision of the mass. The final histopathological reports and immunohistochemistry reports revealed a solitary fibrous tumor. Solitary fibrous tumors (SFTs) are rare tumors in the retroperitoneum. In our search, fewer than a hundred cases have been reported. It has a characteristic "patternless pattern" in a microscopic study. Adverse outcomes of SFTs are associated with atypical features in histology, such as nuclear pleomorphism, necrosis, increased cellularity, and mitoses >4/10 HPF and size more than 10 cm. The standard of care is surgical excision with clear margins. Open surgeries have been done traditionally; we present a case where we performed the excision laparoscopically.

Doege-Potter syndrome associated to metastatic solitary fibrous tumor

Solitary fibrous tumor (SFT) is a rare fibroblastic mesenchymal neoplasm with an estimated annual incidence of 0.35 per 100,000 individuals. Doege-Potter syndrome is a paraneoplastic syndrome related to solitary fibrous tumor clinically characterized by hypoglycemia, occurring in less than 5% of cases. Herein, we report a case of metastatic SFT associated with recurrent severe hypoglycemia. A 43-year-old male with a noncontributory medical history presented with a painless and progressive growing mass in the right thigh. The histological evaluation rendered the diagnosis of SFT, and tumor resection was performed. One year after the operation, on the oncological follow-up, he was admitted to the emergency unit, manifesting an early-morning seizure associated with a severe hypoglycemia. The laboratory findings of non-islet cell tumor hypoglycemia (NICTH) in the background of a relapsed metastatic solitary fibrous tumor were consistent with the diagnosis of Doege-Potter syndrome. Hepatic embolization associated with oral glucocorticoid was an efficient palliative treatment to control the hypoglycemic crisis and allow hospital discharge.

A solitary fibrous tumor in the pelvic cavity of a patient with Doege-Potter syndrome: a case report

BACKGROUND

A solitary fibrous tumor (SFT) is a mesenchymal lesion, which commonly develops in the thorax. Non-islet cell hypoglycemia is a rare paraneoplastic phenomenon caused by an extra-pancreatic tumor. We report a rare case of a pelvic SFT with severe hypoglycemia, which was considered to be Doege-Potter syndrome.

CASE PRESENTATION

A 72-year-old man was referred to our hospital for treatment of hypoglycemia and a large pelvic tumor. His blood glucose level was 52 mg/dl; serum insulin level, 1.0 μIU/ml; C-peptide level, 0.2 ng/ml; and insulin-like growth factor-I (IGF-I) level, 31 ng/ml. Contrast-enhanced computed tomography (CT) showed a 13-cm mass in the pelvic cavity. Magnetic resonance imaging (MRI) revealed a lobulated tumor with iso- and high-intensity areas combined in T2-weighted images. No clear invasion to any adjacent organs was identified. The tumor was resected, and hypoglycemic symptoms disappeared immediately. Pathological diagnosis was an SFT with malignant potential that secreted IGF-II and caused hypoglycemia. There has been no tumor recurrence during the 1 year of follow-up.

CONCLUSION

Non-islet cell tumor hypoglycemia should be considered in the differential diagnosis of patients presenting with tumors and hypoglycemia.

The Diagnostic Value of IGF-2 and the IGF/IGFBP-3 System in Silver-Russell Syndrome

BACKGROUND/AIMS

Recently, we have described a family of 4 members presenting with intrauterine and postnatal growth failure, low IGF-2 levels, and signs of Silver-Russell syndrome (SRS) who carried a genomic IGF2 mutation. Here, we assess the value of IGF-2 in relation to SRS.

METHODS

We collected data from 48 SRS children and 48 short children born small for gestational age (SGA) seen at our center. The SRS children were 4.6 ± 2.0 years of age, and the SGA children were 4.8 ± 1.8 years of age. All patients were prepubertal and growth hormone naive. An 11p15 ICR1 loss of methylation (11p15LOM) was present in 22, maternal uniparental disomy of chromosome 7 (upd(7)mat) in 7, and IGF2 genomic mutation (IGF2mut) in 3 patients. Growth factors were measured by in-house radioimmunoassays.

RESULTS

The median IGF-2 standard deviation scores (SDSs) were: IGF2mut -1.75, upd(7)mat -1.69, nonsyndromic SGA -1.52, 11p15LOM -0.61, and clinical (tested negative) -0.55. The median IGF-2:IGF-1 concentration ratio was 2.57 in IGF2mut compared to 5.44 in 11p15LOM (p = 0.036), 7.84 in clinical, and 7.98 in upd(7)mat. Upd(7)mat patients had significantly lower IGF-1 and IGFBP-3 SDSs than patients with 11p15LOM (p ≤ 0.002).

CONCLUSION

Serum IGF-2 in combination with IGF-1 and IGFBP-3 can add to the clinical signs of SRS patients and help to perform targeted genetic testing. Further studies are needed.

Subcutaneous glucagon infusion and continuous glucose monitoring enable effective management of hypoglycemia in a patient with IGF-2-producing hemangiopericytoma

Background

Ectopic insulin-like growth factor (IGF)-2 production is a rare complication of an array of epithelial and mesenchymal tumors, and can clinically manifest as life-threatening hypoglycemia.

Case presentation

A 49-year-old woman with 13-year history of metastatic hemangiopericytoma, previously treated with multiple rounds of chemotherapy and palliative radiation, presented to the emergency department after a hypoglycemic seizure. On arrival, glucose was 18 mg/dL (1.0 mmol/L) and required continuous dextrose infusion for maintenance within normal limits. Insulin was <2.0 μU/mL, C-peptide 0.1 ng/mL, and beta-hydroxybutyrate <0.2 mmol/L. Random cortisol was 21 μg/dL; sulfonylurea screen, and insulin antibodies were negative. IGF-2 level was 1320 ng/mL; IGF-1 was within normal limits and IGF binding protein (BP)-3 suppressed. Dexamethasone, started at 6 mg twice daily, allowed discontinuation of the glucose infusion. Given concern for nocturnal hypoglycemia, and patient interest in steroid-sparing anti-hypoglycemic regimen, she was also started on overnight continuous subcutaneous glucagon infusion via insulin pump. She was discharged with instructions to maintain a diet high in complex carbohydrates during the day, while utilizing glucagon pump at night. She was also started on continuous glucose monitoring system (CGMS) with an alarm to warn of hypoglycemia. Glucagon infusion rate was later titrated based on CGMS readings. Abdominal CT revealed increasing size of a right upper quadrant mass not previously subjected to radiotherapy. After radiation to this area, hypoglycemia improved, allowing further glucagon titration. In parallel, IGF-2 level declined to 380 ng/mL.

Conclusions

Ectopic IGF-2 production is a rare but often fatal complication of many cancers, and should be considered on the differential diagnosis in patients with malignancy and unexplained hypoglycemia. Once hypoglycemia is diagnosed, patients often have end-stage disease. While treatment of the causative tumor is the only definitive intervention, anti-hypoglycemia therapy is a life-saving, temporizing measure. In this case, the patient attained euglycemia and survived 3 months after presentation before ultimately succumbing to other malignancy-related complications. Given efficacy in management of hypoglycemia while awaiting definitive tumor-directed therapy, we submit nighttime subcutaneous glucagon infusion and CGMS are valuable additions to the physician’s armamentarium in managing this condition.

[Metabolic disorders as paraneoplastic syndromes]

Paraneoplastic syndromes are characterized by the tumor-induced release of peptide hormones and/or the initiation of immune phenomena, which elicit clinical changes and alterations in laboratory parameters independent of the tumor size and spread. In addition to neurological, endocrinal and rheumatological phenotypes, metabolic alterations play a special role in the clinical routine as they commonly present with acute symptoms in an emergency situation and necessitate immediate diagnosis and prompt initiation of treatment. Metabolic alterations within the framework of malignant diseases should be treated in a multidisciplinary team and it is often necessary to perform monitoring and treatment in an intensive care unit. This article focuses on the diagnostic and therapeutic options for metabolic disorders due to paraneoplastic syndromes, such as hypercalcemia, hypocalcemia, hyperglycemia, hypoglycemia and a special variant of tumor-induced metabolic disorders due to tumor lysis syndrome.

Retroperitoneal Solitary Fibrous Tumor: A "Patternless" Tumor

Introduction

Solitary fibrous tumor is a rare type of mesenchymal, spindle-cell tumor reported mostly in the pleura. Retroperitoneal occurrence is rare and histopathological diagnosis is challenging.

Case Presentation

A 55-year-old woman with nonspecific abdominal pain was found to have a retroperitoneal/pelvic mass adjacent to the upper rectum. The patient underwent surgical resection in clear margins of this pelvic tumor, entering the total mesenteric excision surgical plane. Final histopathology revealed a solitary fibrous tumor and the case is presented herein.

Discussion

Solitary fibrous tumor in the retroperitoneum is rarely found in the literature and to the best of our knowledge less than a hundred cases are described so far. Histopathological diagnosis is mostly based on a “patternless pattern” on microscopic examination, which is a storiform arrangement of spindle cells combined with a “hemangiopericytoma-like appearance” and increased vascularity of the lesion. Surgery is the mainstay of treatment and recurrence rates are generally low.

Levels of glucose-regulatory hormones in patients with non-islet cell tumor hypoglycemia: including a review of the literature

Non-islet cell tumor hypoglycemia (NICTH) is one of the causes of spontaneous hypoglycemia. The pathogenesis of NICTH is thought to be an excessive production by tumors of big insulin-like growth factor (IGF)-II. This study investigated the levels of glucose-regulatory hormones in patients with NICTH with high serum levels of big IGF-II (big IGF-II group) and compared these with profiles of patients with spontaneous hypoglycemia with normal IGF-II (normal IGF-II group). Circulating IRI, CPR, ACTH, cortisol, GH, and IGF-I levels measured during hypoglycemic episodes were examined retrospectively in 37 patients with big IGF-II producing NICTH and 6 hypoglycemic patients with normal IGF-II. The hormone profile data of 15 patients with NICTH from published case reports were reviewed and included in the analyses. Mean plasma glucose levels (36 vs. 29 mg/dL), serum IRI (0.53 vs. 0.37 μIU/mL), CPR (0.15 vs. 0.20 ng/mL), IGF-I SDS (-3.55 vs. -3.18 SD) and ACTH levels (27.3 vs. 33.8 pg/mL) were not significantly different between the big and normal IGF-II groups. However, mean serum GH (0.85 vs. 9.62 ng/mL) and plasma cortisol levels (16.2 vs. 34.5 μg/dL) were significantly lower in the big IGF-II group than in the normal IGF-II group (both p<0.05). In conclusion, although the magnitude of the decrease in insulin and IGF-I levels did not differ between spontaneous hypoglycemic patients caused by other etiologies, patients with NICTH tended to have low basal GH levels during hypoglycemic episodes. These differences in hormone profile may be helpful for selecting patients who require analysis of IGF-II.

Paraneoplastic endocrine syndromes

The majority of neoplasms are responsible for symptoms caused by mass effects to surrounding tissues and/or through the development of metastases. However, occasionally neoplasms, with or without endocrine differentiation, acquire the ability to secrete a variety of bioactive substances or induce immune cross-reactivity with the normal tissues that can lead to the development of characteristic clinical syndromes. These syndromes are named endocrine paraneoplastic syndromes when the specific secretory components (hormones, peptides or cytokines) are unrelated to the anticipated tissue or organ of origin. Endocrine paraneoplastic syndromes can complicate the patient's clinical course, response to treatment, impact prognosis and even be confused as metastatic spread. These syndromes can precede, occur concomitantly or present at a later stage of tumour development, and along with the secreted substances constitute the biological 'fingerprint' of the tumour. Their detection can facilitate early diagnosis of the underlying neoplasia, monitor response to treatment and/or detect early recurrences following successful initial management. Although when associated with tumours of low malignant potential they usually do not affect long-term outcome, in cases of highly malignant tumours, endocrine paraneoplastic syndromes are usually associated with poorer survival outcomes. Recent medical advances have not only improved our understanding of paraneoplastic syndrome pathogenesis in general but also enhanced their diagnosis and treatment. Yet, given the rarity of endocrine paraneoplastic syndromes, there is a paucity of prospective clinical trials to guide management. The development of well-designed prospective multicentre trials remains a priority in the field in order to fully characterise these syndromes and provide evidence-based diagnostic and therapeutic protocols.

Spontaneous hypoglycemia: diagnostic evaluation and management

Spontaneous hypoglycemia is a puzzling clinical problem and an important reason for referral to endocrinologists. Several clinical conditions such as insulinomas, non-insulinoma pancreatogenous hypoglycemia syndrome, insulin autoimmune syndrome, postprandial hypoglycemia (reactive hypoglycemia), non-islet cell tumor hypoglycemia, primary adrenal insufficiency, hypopituitarism, and critical illness can be associated with spontaneous hypoglycemia. Rarely, in patients with mental health issues, factious hypoglycemia from extrinsic insulin use or ingestion of oral hypoglycemic agents can obfuscate the clinical picture for clinicians trying to identify an organic cause. In those presenting with Whipple's triad (symptoms ± signs of hypoglycemia, low plasma glucose, and resolution symptoms ± signs after hypoglycemia correction), a 72-h supervised fast test with measurement of plasma insulin, c-peptide, pro-insulin, and beta-hydroxybutyrate levels, coupled with plasma/urine sulphonylurea screen, forms the first step in diagnostic evaluation. A mixed meal test is preferable for those with predominantly postprandial symptoms. Additional non-invasive and/or invasive diagnostic evaluation is necessary if an organic hypoglycemic disorder is suspected. With the aid of a few brief clinical case scenarios, we discuss the diagnostic evaluation and management of spontaneous hypoglycemia through this comprehensive article.

Hypoglyceamia in a Patient with a Solitary Fibrous Tumour

Objective

To illustrate an unusual mechanism causing hypoglycaemia.

Material and methods

A 76-year-old man presented with episodes of agitation and confusion and was resuscitated with oral glucose gel when found to be hypoglycaemic.

Results

A CT scan for an abdominal mass confirmed a solitary fibrous tumour (SFT). The sarcoma multidisciplinary team suggested conservative management. The patient’s episodic hypoglycaemia was managed with diet modification including corn-based starch, scheduled snacks and dexamethasone. Glucose levels were within normal range at discharge from hospital. The patient was referred to the palliative care team for follow-up.

Conclusion

SFTs causing non-islet cell tumour hypoglycaemia are difficult to treat.

LEARNING POINTS