Paraneoplastic hypoglycemia: An overview for optimal clinical guidance.

Paraneoplastic hypoglycemia, also known as non-islet cell tumor hypoglycemia (NICTH), is a rare but critical condition occurring in patients with different types of malignancy. This condition is commonly linked to tumors producing insulin-like growth (IGF) factors, particularly IGF-2 and its precursors, which disrupt glucose homeostasis and lead to excessive glucose consumption. The diagnosis typically involves documenting symptomatic hypoglycemia and ruling out other potential causes. Essential diagnostic tools include imaging studies and laboratory tests, specifically measuring IGF-2 levels and the IGF-2:IGF-1 ratio. Treatment strategies for NICTH are multifaceted and may include surgical resection of the tumor if feasible, pharmacological interventions such as corticosteroids to suppress IGF-2 production, or supportive measures to manage acute hypoglycemic episodes. Novel therapeutic approaches targeting IGF-2, such as monoclonal antibodies or siRNA, are also being explored and hold promise for future treatment options. This review aims to enhance understanding of paraneoplastic hypoglycemia, focusing on its pathogenesis and diagnosis, to guide optimal medical treatment.

Doege-Potter Syndrome: A Solitary Fibrous Tumor Causing Non-Islet Cell Tumor Hypoglycemia.

Doege-Potter syndrome occurs when incompletely processed insulin-like growth factor 2 (IGF-2), also known as big IGF-2, is produced by a solitary fibrous tumor (SFT) and results in non-islet cell tumor hypoglycemia (NICTH). We discuss here the case of a 66-year-old male who presented with a 2-week history of increasing confusion and a serum glucose of 34 mg/dL. The patient's symptoms immediately improved with dextrose. The patient did not use insulin, serum sulfonylurea screen was negative, and testing for adrenal insufficiency was unremarkable. Outpatient laboratory evaluation revealed a serum glucose of 48 mg/dL along with low insulin, C-peptide, and proinsulin levels. Further work-up showed an IGF-2 to IGF-1 ratio of 38:1. A ratio greater than 10:1 is diagnostic of NICTH. Imaging demonstrated a 21-cm mass in the lower abdomen and pelvis. The patient underwent surgical resection. The hypoglycemia resolved immediately postoperatively. Surgical pathology revealed a malignant SFT. In NICTH, big IGF-2 forms a complex that is biologically active and saturates the insulin and IGF receptors, resulting in refractory hypoglycemia. Although glucocorticoids can mitigate hypoglycemia, complete surgical resection is the only definitive treatment of NICTH. This case highlights the importance of maintaining a broad differential for seemingly simple hypoglycemia.

Hypoglycemia From Metastatic Meningeal Solitary Fibrous Tumor Occurring Over Two Decades After Initial Diagnosis.

Despite multiple intracranial and extracranial relapses associated with a widely metastatic meningeal solitary fibrous tumor (formerly classified as hemangiopericytoma), a 66-year-old type 2 diabetic man was first diagnosed with paraneoplastic hypoglycemia 23 years after the original diagnosis and 12 years after the onset of extracranial metastatic disease. An enlarging mass entirely replacing the left kidney measuring 11.6 × 10 × 28 cm, which had not been locally treated before, was considered to be the putative source of IGF-2 excess. The insulin-like effects of IGF-2 not only ameliorated his long-standing type 2 diabetes mellitus, but also caused spontaneous fasting hypoglycemia. The physiopathology, clinical manifestations, diagnostic approach, and treatment of non-islet cell tumor hypoglycemia are briefly discussed here. Palliative tumor debulking improved the hypoglycemia by day 11 after radiation therapy and glucose monitoring with continuous glucose monitoring system (Dexcom G6) facilitated the patient's management and gave him peace of mind.

Three Cases of Non-islet Cell Tumor Hypoglycemia Highlighting Efficacy of Glucocorticoid Treatment.

Non-islet cell tumor hypoglycemia (NICTH) is a rarely encountered cause of hypoglycemia. It is most often caused by tumor secretion of precursor insulin-like growth factor-2 (IGF-2) which, in high concentrations, binds to insulin receptors exerting insulin-like metabolic effects. It is often associated with mesenchymal and hepatic tumors. We describe 3 cases of NICTH: a 60-year-old man with an unresectable pelvic sarcoma and two women ages 43 and 57 with metastatic hemangiopericytoma. Biochemical assessment identified hypoglycemia associated with suppressed insulin, c-peptide, and beta-hydroxybutyrate levels. Each patient was treated with oral glucocorticoids, which effectively prevented recurrence of hypoglycemia and this effect was sustained long-term. These cases highlight a rarely encountered but important cause of hypoglycemia and demonstrate the long-term efficacy of glucocorticoid treatment in preventing hypoglycemia in cases of NICTH related to surgically unresectable tumors.

Solitary fibrous tumor with IGF-II-induced non-islet cell tumor hypoglycemia: a case report and molecular characterization by next-generation sequencing.

Background: Non-islet cell tumor-induced hypoglycemia (NICTH) is a rare, life-threatening medical condition caused by excessive insulin-like growth factor II (IGF-II) secretion from tumors of most commonly mesenchymal origin. Using next-generation sequencing, we have characterized the genome and transcriptome of the resected IGF-II-secreting solitary fibrous tumor from a patient with severe hypoglycemia accompanied by hypoglycemia unawareness. Case presentation: A 69-year-old male patient presenting with abdominal discomfort was examined using computer tomography, revealing a large lesion at the lesser pelvis extending above the umbilicus. As no bone and lymph node metastases were detected, the patient was scheduled for laparotomy. Before surgery, the patient presented with symptoms of severe hypoglycemia. Suppressed C-peptide levels and subsequent hypokalemia indicated a possible case of NICTH. The patient was treated with methylprednisolone (8 mg) to assess hypoglycemia. After the surgery, mild hypoglycemia was present for the postoperative period, and no radiological recurrences were observed 3 and 12 months after discharge. Histopathological examination results were consistent with the diagnosis of malignant solitary fibrous tumor (SFT). Overexpression of IGF-II was confirmed by both immunohistochemistry and RNA sequencing. Further NGS analysis revealed an SFT characteristic alteration-NAB2-STAT6 fusion. Additionally, three deleterious missense variants were detected in oncogenes BIRC6, KIT, and POLQ, and one homozygous in-frame deletion in the RBM10 tumor suppressor gene. Conclusion: While the NAB2-STAT6 fusions are well characterized, the mutational landscape of SFTs remains understudied. This study reports the importance of NGS to characterize SFTs as we detected four coding variants in genes (BIRC6, KIT, POLQ, and RBM10) associated with tumorigenesis that could potentially contribute to the overall pathogenesis of SFT.

Doege-Potter Syndrome; A Case of Solitary Fibrous Pleura Tumor Associated with Severe Hypoglycemia: A Case Report in Internal Medicine.

BACKGROUND: Doege-Potter syndrome is a rare paraneoplastic entity that is often diagnosed incidentally during the work-up of hypoglycemia of unclear etiology. It is characterized by a non-islet cell tumor hypoglycemia mostly associated with solitary fibrous tumors. These uncommon tumors have been reported in <5% of solitary fibrous tumors. Although not unique in its kind, this case is extremely important as this syndrome often conceals unrecognized tumors that can be surgically resolved. CASE PRESENTATION: We present the case of a 59-year-old non-diabetic man with a 2-month history of severe and recurrent fasting hypoglycaemia presenting with severe dyspnea and sweating. Further workup revealed low insulin, C-peptide, and IGF-1 levels and a large right in-trathoracic solitary fibrous tumor. Unfortunately, bioassays for IGF-2 were unavailable at our hos-pital. Nevertheless, as hypoglycemia completely resolved after resection of the mass, Doege-Potter syndrome was highly suspected. CONCLUSION: Doege-Potter syndrome is a complication of rare tumors. If hy-poglycemia is unexplained, this syndrome should always be suspected, and the presence of un-known masses should be investigated.

Resolution of paraneoplastic hypoglycemia following nephroureterectomy for treatment of canine renal cell carcinoma: Case report.

Objectives: To describe the clinicopathologic findings, imaging results, surgical treatment, and outcome of a dog with renal cell carcinoma (RCC) and paraneoplastic hypoglycemia. Animals: A 13-year-old female spayed mixed breed dog that was presented for facial twitching and neurologic decline and diagnosed with a renal mass and paraneoplastic hypoglycemia. Study design: Case report. Methods: Serum chemistry revealed severe hypoglycemia and normal renal values. Abdominal ultrasonography showed a large, heterogeneous, cavitated mass associated with the left kidney and no evidence of abdominal metastatic disease. Thoracic radiographs revealed no evidence of pulmonary metastatic disease. Fasted serum insulin was low concurrently with severe hypoglycemia. No other causes of hypoglycemia were detected, and paraneoplastic hypoglycemia was suspected. Results: After initial medical management of the dog's hypoglycemia, left nephroureterectomy was performed. Histopathology was consistent with RCC. Postoperatively, the dog's hypoglycemia resolved, and supplementation was discontinued. The dog remained stable and was discharged from the hospital 3 days after surgery. At 2-week, 3-month, and 5-month follow up evaluations, the dog remained euglycemic, and no definitive evidence of disease progression was detected. Eight months postoperatively, the dog was euthanized due to decline in mobility. Necropsy and histopathology revealed cerebral and spinal cord multifocal myelin sheath dilation and two primary pulmonary carcinomas with no evidence of recurrence or metastasis of the RCC. Conclusion: Surgical treatment of RCC with subsequent resolution of paraneoplastic hypoglycemia has not previously been reported in veterinary medicine. In this dog, nephroureterectomy for RCC resulted in immediate and sustained resolution of paraneoplastic hypoglycemia.

Non-islet cell tumor hypoglycemia associated with Gastrointestinal Stromal Tumor: Case report and review of the literature.

Non-islet cell tumor hypoglycemia is an uncommon paraneoplastic phenomenon commonly associated with tumors of mesenchymal origin like gastrointestinal stromal tumors (GIST). It causes the release of insulin-like growth factor type II. GIST are frequently asymptomatic but can present with vague symptoms such as gastrointestinal bleeding, gastric pain, anorexia, nausea, and vomiting. We present an interesting case of A 62-year-old male with GIST tumor admitted for refractory hypoglycemia found to have non-islet cell tumor hypoglycemia which is a relatively uncommon cause of hypoglycemia.

Big insulin-like growth factor 2-producing multiple solitary fibrous tumors treated with debulking surgery: A case report.

Background: Non-islet cell tumor hypoglycemia (NICTH) is a rare paraneoplastic syndrome caused by a tumor-producing high molecular weight form of insulin-like growth factor 2 (IGF2) known as big IGF2. The only curative treatment for this condition is surgical resection of the responsible tumors. However, this may not be feasible in cases with multiple metastases at diagnosis of NICTH, and no standard treatment strategy for multiple tumors has been established. The effects of pharmacological therapies including somatostatin analogs are often inefficient and remain difficult to predict. Case description: A 68-year-old man was admitted to our hospital due to impaired consciousness and severe hypoglycemia. His medical history included diagnosis of a left temporal solitary fibrous tumor (SFT) at the age of 48 years, after which local recurrent and metastatic tumors were repeatedly resected. Four years before admission, multiple intraabdominal and subcutaneous tumors were detected and, being asymptomatic, were managed conservatively. Laboratory exam on admission demonstrated hypoglycemia accompanied with low serum insulin and IGF1 levels. Computed tomography (CT) scan revealed multiple intraabdominal and subcutaneous tumors increasing in size. Serum big IGF2 was detected on immunoblot analysis, and he was diagnosed as NICTH. In addition, tumor uptake was observed on 68Ga-labelled 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid-d-Phe1-Tyr3-octreotide positron emission tomography/CT (DOTATOC-PET/CT). Since larger tumor is more suspicious about responsible producibility of big IGF2, we planned to resect large ones preferentially and reduce the amounts of residual tumors. Debulking surgery was performed by removing eleven intraabdominal tumors; the hypoglycemia was then completely corrected. Histological analyses revealed the resected tumors to be metastases of SFT having somatostatin receptor 2 expression. In immunoblot analysis, the resected tumors were found to be positive for big IGF2; serum big IGF2 was undetectable after surgery. Conclusion: We present a case of NICTH with multiple metastatic SFTs. We strategically performed debulking surgery, which led to remission of hypoglycemia. This result demonstrates a pioneering practical solution for NICTH cases with multiple tumors. In addition, in cases of SFTs presenting with NICTH, positivity of DOTATOC-PET/CT as well as single-dose administration of octreotide may be predictive of the efficacy of somatostatin-based therapy.

Non-islet cell tumor hypoglycemia concurrent with acromegalic features: A case report and literature review.

Background: Non-islet cell tumor hypoglycemia (NICTH) is a rare cause of hypoglycemia due to the overproduction of high molecular weight insulin-like growth factor (big-IGF2), which activates the insulin receptor and subsequently caused hypoglycemia. But NICTH with acromegaly had rarely been reported. We firstly reported a rare case of NICTH concurrent with acromegalic facial features induced by a retroperitoneal hemangiopericytoma and reviewed similar cases in the literature. Case presentation: A 30-year old man was admitted to hospital because of recurrent unconscious, which usually occurred in the late afternoon or early morning before supper or breakfast. On one unconscious occasion, his blood glucose was 2.4 mmol/L. His consciousness recovered rapidly with intravenous 50% glucose administration. Physical examination showed that he had coarse oily facial features with acne, prominent forehead and brow, broad nose, prominent nasolabial folds. At the time of hypoglycemia, suppressed serum insulin, GH and IGF-1 levels was found. Computed Tomography further revealed a large left retroperitoneal mass measuring 7.0 cm × 12.3 cm × 13.0 cm. He underwent complete surgical resection of the mass. Surgical pathology demonstrated a hemangiopericytoma and strong positive for IGF-2. He did not experience further episodes of hypoglycemia after the operation during the 2.5 years follow-up. Conclusions: Fibrous origin is the most common tumor type for NICTH with acromegaly features. NICTH should be considered in non-diabetic patients who have recurrent hypoglycemia along with suppressed serum insulin and IGF-1 levels.

Duplication of AKT2 Gene in Ovarian Cancer: A Potentially Novel Mechanism for Tumor-Induced Hypoglycemia.

Severe hypoglycemia occurs with different types of tumors, including islet cell and non-islet cell tumors. Non-islet cell tumor hypoglycemia (NICTH) is a rare and potentially life-threatening complication of malignancy. The primary underlying mechanism of NICTH proposed in the literature includes paraneoplastic overproduction of insulin-like growth factor-2 (IGF-2), the production of autoantibodies against insulin or its receptors, or the presence of extensive metastatic burden replacing hepatic tissue or adrenal glands. In this report, we propose a potentially novel mechanism underlying NICTH involving stimulation of the insulin signaling pathway in a 58-year-old woman with a rare ovarian tumor of Müllerian origin that carries a duplication of the AKT2 gene. AKT2 is a molecular mediator of insulin signaling. To our knowledge, this is the first reported case of tumor-induced hypoglycemia associated with AKT2 gene duplication. In this report also, we discuss the currently available diagnostic modalities and highlight the therapeutic rationale in patients with NICTH, a highly vulnerable population.

Well-differentiated liposarcoma causing non-islet cell tumor hypoglycemia.

Non-islet cell tumor hypoglycemia (NICTH) is a paraneoplastic syndrome that causes severe hypoglycemia. The tumor involved produces high-molecular-weight insulin-like growth factor-II (IGF-II). NICTH can be caused by various benign and malignant tumors. However, NICTH due to liposarcoma (LPS) is rare. A 38-year-old man was brought to the hospital emergency department with complaints of vomiting and unconsciousness. His abdomen was distended, and a large tumor was palpable. He had severe hypoglycemia that required continuous glucose infusion. Radiological examination revealed a large 40-cm mass that filled the abdominal cavity, and LPS of the mesentery was suspected. Laboratory data showed low levels of insulin, C-peptide, and IGF-I concentrations. Subsequently, an LPS-induced NICTH was suspected. Complete resection of the tumor and the encased small intestine was performed. The pathological diagnosis was well-differentiated liposarcoma (WDLPS). The Western immunoblot showed that the high-molecular-weight IGF-II confirmed in the serum preoperatively, had almost disappeared postoperatively. Based on these findings, NICTH caused by a WDLPS was diagnosed. The postoperative course was uneventful. In the last 4 years since the primary operation, the patient had not experienced further hypoglycemia symptoms. Here, we report a case of NICTH caused by a large WDLPS. NICTH should be considered in patients with both severe hypoglycemia and large tumors. In these cases, appropriate treatment including semi-urgent surgery should be provided.

Severe Hypoglycemia Caused by a Giant Borderline Phyllodes Tumor of the Breast: A Case Report and Literature Review.

A case of hypoglycemic coma caused by a giant borderline phyllodes tumor of the breast has been described. The patient, a 63-year-old woman, was admitted with recurrent unconsciousness. She had a giant breast tumor with decreased blood glucose, insulin, and C-peptide. The patient's hypoglycemia resolved rapidly after resection of the breast tumor. Pathological examination indicated a borderline phyllodes tumor of the breast, and immunohistochemistry suggested high expression of insulin-like growth factor-2 (IGF-2) in the tumor tissue. A literature review is also included to summarize the clinical characteristics of such patients and to serve as a unique resource for clinical diagnosis and treatment of similar cases.

Non-islet cell tumor hypoglycemia in a patient with uterine carcinosarcoma.

•Non-islet cell tumor hypoglycemia (NICTH) is a rare cause of hypoglycemia in patients with uterine carcinosarcoma.•Complete surgical resection is the first-line treatment for NICTH.•In patients with tumors not amenable to complete resection, partial resection can provide improvement in severe hypoglycemia.

Insulin-like growth factor II-producing colonic carcinoma presenting with non-islet cell tumor hypoglycemia: An autopsy report revealing neuroendocrine differentiation in the metastatic foci and literature review.

Non-islet cell tumor hypoglycemia (NICTH) is a very rare symptom of severe hypoglycemia associated with extrapancreatic tumors. It is considered to be caused by insulin-like growth factor (IGF)-II. There have been no autopsy cases of colorectal carcinoma with NICTH confirmed with both serum high molecular weight and tumoral IGF-II. We report the case of a 46-year-old woman with advanced sigmoid colon cancer and liver metastases. She underwent open sigmoidectomy, and histologically, the lesion was a differentiated-type tubular adenocarcinoma. Postoperative chemotherapy was initiated. However, she experienced repeated hypoglycemia attacks 10 months after the operation, while the liver metastases increased. We examined the cause of hypoglycemia, and finally diagnosed her with NICTH associated with high molecular weight IGF-II production, which was proven by Western immunoblot of the serum. She died 12 months after surgery and was examined by autopsy. Liver metastases showed a transition from adenocarcinoma to carcinoma with neuroendocrine differentiation. Immunohistochemistry showed that both metastatic carcinoma of the liver and primary colonic adenocarcinoma were positive for IGF-II. Neuroendocrine differentiation in liver metastases proven by an autopsy may have contributed to tumor growth, which may have exacerbated the symptoms.

Paraneoplastic Hypoglycemia Leading to Insulin Independence in a Patient With Type 1 Diabetes.

OBJECTIVE: Non-islet cell tumor hypoglycemia (NICTH) is an uncommon paraneoplastic syndrome associated with mesenchymal neoplasms such as gastrointestinal stromal tumors (GISTs). We report the case of a patient with type 1 diabetes (T1D) and recurrent GIST who not only required discontinuation of insulin therapy but also required continuous parenteral glucose infusions to prevent hypoglycemia. METHODS: A 59-year-old woman with a 24-year history of T1D and recurrent GIST presented with frequent episodes of symptomatic hypoglycemia despite continuous reductions in her insulin therapy. Laboratory workup revealed undetectable insulin and C-peptide, low insulin-like growth factor (IGF) 1, normal IGF-2, and an elevated IGF-2:IGF-1 ratio. Medical management with prednisone alone and, later, in combination with octreotide did not reduce hypoglycemic episodes. Eventually, during hospitalization for severe hypoglycemia, she was treated and discharged with continuous intravenous dextrose infusion. She ultimately required around-the-clock glucose infusions, which helped her maintain what she believed was an acceptable quality of life during her remaining weeks. DISCUSSION: NICTH is characterized by excessive tumor production of IGF-2 or pro-IGF-2, leading to unrestricted glucose uptake in peripheral tissues and hypoglycemia. A diagnosis of NICTH can be made on the basis of low IGF-1 levels in the plasma with normal or elevated IGF-2. Tumor resection is the most definitive treatment for NICTH. CONCLUSION: This patient with T1D presented with resistant hypoglycemia due to recurrence of an enlarging GIST. She required discontinuation of all insulin therapy and continuous dextrose infusions to maintain euglycemia.

Doege-Potter Syndrome with a Benign Solitary Fibrous Tumor: A Case Report and Literature Review.

Doege-Potter syndrome is a rare paraneoplastic syndrome that is often diagnosed incidentally during the workup of hypoglycemia of unclear etiology. It is characterized by a non-islet cell tumor hypoglycemia secondary to excessive production of partially processed IGF-II hormone from a solitary fibrous tumor (SFT). Often these tumors are intrathoracic, benign, and asymptomatic. Occasionally they present as a paraneoplastic event; hypertrophic osteoarthropathy in Pierre-Marie-Bamberger syndrome and hypoglycemia in Doege-Potter syndrome. The NAB2-STAT6 gene fusion is the hallmark of the SFT. Complete surgical resection of the tumor often results in resolution of symptoms and cure in most cases. Here we present the case of an 83-year-old non-diabetic female with recurrent syncopal events who was diagnosed with the Doege-Potter syndrome secondary to a SFT of pleura. Her tumor was positive for NAB2-STAT6 gene fusion on RT-PCR. Following the resection of the giant tumor mass, she became symptom-free within 24 h, and has remained asymptomatic at 4 months follow-up.

A Giant Borderline Phyllodes Tumor of Breast With Skin Ulceration Leading to Non-Insular Tumorigenic Hypoglycemia: A Case Report and Literature Review.

Phyllodes tumor (PT) is a special type of breast tumors, including three types: malignant, borderline, and benign. Most of these tumors form unilateral disease and can rapidly increase in size. The occurrence of axillary lymph node metastasis is rare. Tumor-associated hypoglycemia can be divided into non-islet cell tumor and insulinoma. In non-islet cell tumor hypoglycemia (NICTH), a considerable high molecular weight form of insulin like growth factor 2 (IGF-2) is formed, which abnormally binds to insulin receptors in the tissues and causes hypoglycemia. Breast phyllodes tumors with NICTH are rare and first reported in 1983. Surgical resection is the main treatment and hypoglycemia symptoms usually resolve after surgery. Nevertheless, prior to surgery, intravenous glucose infusion is used to maintain blood glucose levels. A female patient presented with a rapidly growing breast mass and was diagnosed with a phyllodes tumor with NICTH at our hospital in August 2020; she was successfully treated through surgical resection. We reviewed the relevant literature to investigate and analyze the relationship between NICTH and phyllodes tumors, as well as optimize its diagnosis and treatment.

Non-Islet Cell Tumor Hypoglycemia Caused by Recurrent Pelvic Solitary Fibrous Tumor.

Non-islet cell tumor hypoglycemia is a rare paraneoplastic condition caused by an extra-pancreatic tumor. We report a rare case of hypoglycemia caused by a relapsing pelvic solitary fibrous tumor associated with Big-IGF-2 production. A 72-year-old woman was admitted to our hospital because of loss of consciousness and hypoglycemia. She had a history of ovarian solitary fibrous tumor, which has relapsed. From investigation, serum levels of insulin and C-peptide were suppressed; IGF-1 was slightly reduced and IGF-2 was within the normal range, but the IGF-2: IGF-1 ratio was elevated, indicating the presence of Big-IGF-2 secreting non-islet cell tumor. Contrast-enhanced computed tomography (CT) showed a large pelvic mass. She was then submitted to surgical resection of the mass, which histologically proved to be a solitary fibrous tumor. Three months later, she remains asymptomatic. Non-islet cell tumor hypoglycemia should be considered in the differential diagnosis of patients presenting with tumors and recurrent hypoglycemia.

Late-onset non-islet cell tumor hypoglycemia: A case report.

BACKGROUND: Hypoglycemia due to non-insulin-producing tumors is referred to as non-islet cell tumor hypoglycemia (NICTH). As NICTH is a rare lesion, the natural course of NICTH is not well understood. We report a case of NICTH that was observed 30 years before the onset of hypoglycemia. CASE SUMMARY: A 50-year-old man was diagnosed with an abnormal right chest shadow during a routine X-ray examination, but no further examination was undertaken because the lesion appeared benign. Thirty years after the tumor discovery, the patient was admitted to the hospital with symptoms of severe hypoglycemia, which was diagnosed as NICTH based on a complete examination. The tumor was resected and found to be a solitary fibrous mass (15.6 cm × 13.7 cm × 10.4 cm); thereafter, the patient's blood glucose levels normalized and he completely recovered. CONCLUSION: NICTH can have an acute onset, even if the tumor has been present and asymptomatic over a long time period.