Hypoglycemia mediated by paraneoplastic production of Insulin like growth factor-2 from a malignant renal solitary fibrous tumor - clinical case and literature review

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.

A systematic review of literature on Insulin-like growth factor-2-mediated hypoglycaemia in non-islet cell tumours

INTRODUCTION

Insulin-like growth factor-2 (IGF-2)-mediated hypoglycemia is a rare yet clinically significant entity with considerable morbidity and mortality. Existing literature is limited and fails to offer a comprehensive understanding of its clinical trajectory, management and prognostication.

METHODS

Systematic review of English-language articles reporting primary patient data on IMH was searched using electronic databases (PubMed, Scopus and Embase) from any date up to 21 December 2022. Data were analysed in STATA-16.

RESULTS

The systematic review contains 172 studies, including 1 Randomised controlled trial, 1 prospective observational study, 5 retrospective observational studies, 150 case reports, 11 case series and 4 conference abstracts. A total of 233 patients were analysed, averaging 60.6 ± 17.1 years in age, with comparable proportions of males and females. The commonest tumours associated with Insulin-like Growth Factor-2-mediated hypoglycaemia were fibrous tumours (N = 124, 53.2%), followed by non-fibrous tumours originating from the liver (N = 21, 9%), hemangiopericytomas (N = 20, 8.5%) and mesotheliomas (N = 11, 4.7%). Hypoglycaemia was the presenting feature of NICT in 42% of cases. Predominant clinical features included loss of consciousness (26.7%) and confusion (21%). The mean IGF-2 and IGF-1 levels were 882.3 ± 630.6 ng/dL and 41.8 ± 47.8, respectively, with no significant correlation between these levels and patient outcomes. Surgical removal was the most employed treatment modality (47.2%), followed by medication therapy. The recovery rate was 77%, with chronic liver disease (CLD) significantly associated with a poor outcome (OR: 7.23, P: 0.03). Tumours originating from fibrous tissues were significantly associated with recovery (p < .001). In the logistic regression model, CLD remained a significant predictor of poor outcomes.

CONCLUSION

This systematic review highlights that most non-islet-cell tumour-hypoglycaemia (NICTH) is due to fibrous tumours. NICTs demonstrate a variable prognosis, which is fair if originating from fibrous tissue. Management such as octreotide, corticosteroids, diazoxide, embolization, radiotherapy and surgical resection have disparate success rates.

Addressing recurrent hypoglycaemia through thoracic surgical intervention: understanding Doege-Potter syndrome, a rarity in syndromes

Doege-Potter syndrome (DPS), a rare paraneoplastic phenomenon characterised by non-islet cell tumour hypoglycaemia (NICTH), presents clinicians with intricate diagnostic and therapeutic challenges. This comprehensive review consolidates current understanding, clinical presentations, diagnostic modalities, therapeutic interventions, and emerging trends in managing DPS. The pathophysiology of DPS revolves around dysregulated insulin-like growth factors (IGF), particularly IGF-2, produced by mesenchymal tumours, notably solitary fibrous tumours (SFT). Clinical manifestations encompass recurrent hypoglycaemic episodes, often distinct from typical hypoglycaemia, with implications for insulin and counterregulatory hormone levels. Diagnosis necessitates a multidisciplinary approach integrating biochemical assays, imaging studies, and histopathological confirmation of the underlying neoplasm. Surgical resection remains the cornerstone of treatment, complemented by adjunctive therapies to manage persistent hypoglycaemia. Prognosis is influenced by successful tumour resection and long-term surveillance for recurrence. A patient-centred approach, incorporating supportive services and multidisciplinary care, is essential for optimal outcomes in individuals affected by DPS.

Recurrence of solitary fibrous tumor of the pleura with hypoglycemia (Doege-Potter Syndrome): a case report description

Hypoglycemia has multiple causes, but the most common is a complication of insulin treatment. In addition to insulin therapy, tumors such as insulinomas of pancreatic origin and extrapancreatic tumors causing paraneoplastic syndromes should also be considered. Solitary fibrous tumors of the pleura (SFTP) is rare tumor, which when associated with hypoglycemia causes Doege-Potter syndrome. This article reports a case of a 69-year-old man with Doege-Potter syndrome and underwent the first surgical resection for SFTP. However, the tumor recurred 9 years later with hypoglycemic symptoms and implant metastasis. This recurrent tumor originated from the visceral pleura, was more aggressive and invaded the diaphragm and parietal pleura. After the second surgical removal of the tumor, the hypoglycemic symptoms disappeared.

Clinical Presentation and Diagnostic Approach to Hypoglycemia in Adults Without Diabetes Mellitus

OBJECTIVE

To review the clinical presentation, causes, and diagnostic approach to spontaneous hypoglycemia in adults without diabetes mellitus.

METHODS

A literature review was performed using the PubMed and Google Scholar databases.

RESULTS

Hypoglycemia is uncommon in people who are not on glucose-lowering medications. Under normal physiologic conditions, multiple neural and hormonal counterregulatory mechanisms prevent the development of abnormally low levels of plasma glucose. If spontaneous hypoglycemia is suspected, the Whipple triad should be used to confirm hypoglycemia before pursuing further diagnostic workup. The Whipple criteria include the following: (1) low levels of plasma glucose, (2) signs or symptoms that would be expected with low levels of plasma glucose, and (3) improvement in those signs or symptoms when the level of plasma glucose increases. Spontaneous hypoglycemia can be caused by conditions that cause endogenous hyperinsulinism, including insulinoma, postbariatric hypoglycemia, and noninsulinoma pancreatogenous hypoglycemia. Spontaneous hypoglycemia can also be seen with critical illness, hepatic or renal dysfunction, hormonal deficiency, non-diabetes-related medications, and non-islet cell tumors. The initial diagnostic approach should begin by obtaining a detailed history of the nature and timing of the patient's symptoms, medications, underlying comorbid conditions, and any acute illness. A laboratory evaluation should be conducted at the time of the spontaneous symptomatic episode. Supervised tests such as a 72-hour fast or mixed-meal test may be needed to recreate the situation under which the patient is likely to experience symptoms.

CONCLUSION

We provide an overview of the physiology of counterregulatory response to hypoglycemia, its causes, and diagnostic approaches to spontaneous hypoglycemia in adults.

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.

Solitary Fibrous Tumor of Adrenal Gland and Review of the Literature

Solitary fibrous tumor (SFT) is a rare and still controversial entity. This type of tumor first appeared in the literature as a pleural lesion, but, over the last decades, it has been reported in many extrathoracic sites. As a tumor of the adrenal gland, SFT is still rare and very uncommon, thus extensive research among the English language literature has been performed. We present here a case report of an adrenal SFT which is compared to 11 other known cases. Our case report is from a patient with SFT on the left adrenal gland, followed by mild symptoms of abdominal discomfort and hypertension. Physical examination, laboratory, and radiological tests were performed. The patient underwent surgery and the material was sent for histopathologic analysis for a definite diagnosis. Regular follow up appointments were performed over the course of two years. No recurrence of the tumor has been detected. We explain the symptoms, diagnosis, treatment, and additionally we describe the results and implications of the findings reported in the literature. Correct diagnosis is mandatory for optimal management of solitary fibrous tumor patients.

Doege-Potter syndrome in a facial solitary fibrous tumor: Diagnose and clinical management discussion

Doege-Potter syndrome is a rare hypoglycemic paraneoplastic disorder. This case describes that severe and symptomatic hypoglycemia can occasionally be due to a rare malignant neoplasm, and the differential diagnosis of malignancy should not be overlooked in this setting.

Pazopanib-associated secondary adrenal insufficiency in a patient with malignant solitary fibrous tumor

INTRODUCTION

Pazopanib is an agent that is being successfully used in soft tissue sarcomas. Some endocrine side effects may develop during pazopanib treatment. Here, we presented a case diagnosed with secondary adrenal insufficiency while being investigated for etiology of hypoglycemia which developed after pazopanib.

CASE REPORT

A 69-year-old male patient was operated in June 2019 due to a lung mass 26 × 18 × 10 cm in size. Pathological diagnosis revealed a solitary fibrous tumor with malignant behavior. The patient received three lines of chemotherapy. After pazopanib treatment, a hypoglycemic attack was reported.Management and outcome: Blood cortisol and ACTH (Adrenocorticotropic hormone) levels were not increased at the time of the hypoglycemic attack, and levels of other pituitary hormones were found to be normal. Electrolyte levels were in normal range. Since the counteracting hormone did not reach a sufficient level, it was considered secondary adrenal insufficiency. Hypoglycemic attacks did not occur during follow-up while taking steroid therapy and pazopanib.

DISCUSSION

A single case of primary adrenal insufficiency has been reported in the literature. We here present a case who developed hypoglycemia after pazopanib and was diagnosed with drug-associated secondary adrenal insufficiency. When hypoglycemia develops during pazopanib treatment, we must be aware of adrenal insufficiency.

Hipoglucemia tumoral dependiente y no dependiente de células β-pancreáticas, un reto diagnóstico

La hipoglucemia es una urgencia médica frecuente que en la mayoría de los casos es secundaria al uso de fármacos hipoglucemiantes, orales o inyectados, indicados en pacientes con diabetes mellitus. No obstante, puede presentarse en forma espontánea y severa relacionándose con múltiples condiciones clínicas, incluyendo las neoplasias. Ante una hipoglucemia de origen paraneoplásico se deben reconocer los mecanismos fisiopatológicos que la generan y establecer el diagnóstico oportuno y preciso para disminuir las complicaciones propias de este síndrome clínico. Presentamos dos pacientes con cuadro de hipoglucemia refractaria al manejo médico inicial, de aparición similar con patologías diferentes. El primer caso corresponde a un paciente con insulinoma y el segundo con un hemangiopericitoma.

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.

Extraordinarily long-inactive solitary fibrous tumor transformed to produce big insulin-like growth factor-2, leading to hypoglycemia and rapid liposarcoma growth: a case report

BACKGROUND

A high-molecular-weight form of insulin-like growth factor-2 (IGF-2), known as "big" IGF-2, is occasionally produced by various tumor types, leading to hypoglycemia. Although solitary fibrous tumor (SFT) is a rare mesenchymal neoplasm, it has been estimated that 4-6% of SFT patients develop hypoglycemia due to circulating big IGF-2. The mean time elapsed from tumor detection until the onset of hypoglycemia is reportedly less than one year (8.5 ± 1.9 months).

CASE PRESENTATION

A 68-year-old man was hospitalized for exacerbation of recurring hypoglycemic episodes. He had been diagnosed with an SFT 17 years before the onset of hypoglycemia, and the SFT had already been very large at that time. The tumor, which was non-resectable and refractory to chemotherapies, had slowly increased in size since the initial diagnosis. Half a year before the hypoglycemic episodes manifested, another tumor, adjacent to the left kidney, was newly identified. Fluorodeoxyglucose positron emission tomography-computed tomography scanning, revealed the left peri-renal tumor to show much higher fluorodeoxyglucose uptake than the preexisting SFT, suggesting that it was unlikely to be a metastasis from the SFT. Abundant serum big IGF-2 was detected by western immunoblot analysis, indicating it to be the cause of the hypoglycemia. Since the 17 years between SFT detection and the onset of IGF-2-induced hypoglycemia was an extremely long period as compared with those in previous reports, we initially suspected that the new, peri-renal tumor had produced big IGF-2, but transcatheter arterial embolization of its feeding arteries did not suppress hypoglycemia. Notably, by measuring the tumor volume doubling time, the peri-renal tumor growth was shown to be markedly accelerated in parallel with exacerbation of the hypoglycemia. The patient died of heart failure 21 months after the onset of hypoglycemia. Unexpectedly, autopsy revealed that big IGF-2 had been produced only by the preexisting SFT, not the peri-renal tumor, and that the peri-renal tumor was a dedifferentiated liposarcoma.

CONCLUSIONS

We should keep in mind that even a long-inactive SFT can undergo transformation to produce big IGF-2, which then acts on both insulin and IGF-1 receptors, possibly leading to both hypoglycemia and the development/growth of another tumor, respectively.

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.

Overexpression of IGF2 and IGF2 receptor in malignant solitary fibrous tumor with hypoglycemia: a case report

Background

Solitary fibrous tumor (SFT) is a prototypical mesenchymal neoplasm that induces non-islet cell tumor hypoglycemia (NICTH) due to overproduction of insulin-like growth factor 2 (IGF2). We here report the case of a malignant SFT associated with a hypoglycemia attack.

Case presentation

An 81-year-old man with a large subphrenic mass presented with hypoglycemia and loss of consciousness. His serum insulin and IGF1 levels were relatively low, suggesting an excessively high serum IGF2 levels. Preoperative Western blotting of serum confirmed the overproduction of high-molecular-weight IGF2. After total tumor resection, the patient recovered from hypoglycemia without the need for further treatment. Histological examination revealed proliferation of spindle cells and frequent nuclear mitoses with STAT6 and CD34 immunoreactivity, which led to the diagnosis of malignant SFT. IGF2 was strongly upregulated in the tumor upon immunohistochemistry, consistent with the report of NICTH. In addition, the tumor expressed IGF2 receptor (IGF2R) but not IGF1R.

Conclusions

The present results indicate that the tumor co-expressed IGF2 and IGF2R. IGF2R has not previously been recognized as a tyrosine kinase receptor participating in cell signal transduction. Thus, further case series are required to determine whether IGF2R overexpression reflects the action of an unknown autocrine/paracrine system involving IGF2 for cell proliferation or for the scavenging and degradation of IGF2.

Recurrent Severe Hypoinsulinemic Hypoglycemia Responsive to Temozolomide and Bevacizumab in a Patient With Doege-Potter Syndrome

Nonislet cell tumor hypoglycemia is rare. We highlight the diagnosis and treatment of recurrent severe hypoglycemia in a 49-year-old woman with malignant solitary fibrous tumor of the pleura (Doege-Potter syndrome). The clinical, laboratory and radiologic findings of the case are presented and a brief literature review is provided. Of note, imaging studies showed a large mass in the right hemithorax and pathology and immunehistochemical stains confirmed a malignant solitary fibrous tumor of the pleura. She was a poor surgical candidate owing to a large tumor burden. She was treated with a combination of temozolomide and bevacizumab to which she responded with resolution of hypoglycemia. The treatment of choice for hypoglycemia in patients with the Doege-Potter syndrome is surgical excision. We here report that a combination of temozolomide and bevacizumab may be a viable option in patients with inoperable disease.

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.

Severe Hypoglycemia Caused by Lenalidomide

Lenalidomide is commonly used for multiple myeloma as either induction or maintenance therapy. The agent is associated with a host of adverse effects, but hypoglycemia has only been reported in one phase I trial in patients with solid tumors. We describe a 74-year-old woman who experienced grade 3 hypoglycemia (blood glucose level 35 mg/dl) likely related to lenalidomide. Her medical history was significant for refractory myeloma and type 2 diabetes mellitus. Lenalidomide was started as maintenance therapy following autologous bone marrow transplantation. Approximately 3 years later, she developed refractory hypoglycemia necessitating hospital admission despite stopping antihyperglycemic agents 4 weeks prior to admission. Lenalidomide was withheld during her admission and restarted 2 days prior to discharge. Work-up for causes of persistent hypoglycemia was negative, and her glucose levels improved over her 26-day hospitalization. She was readmitted approximately one month later for hypoglycemia, and lenalidomide was permanently discontinued. Again, work-up for causes of hypoglycemia was negative, and her glucose levels stabilized over her hospitalization. After discontinuation of lenalidomide, hypoglycemia did not recur, and within 1 year the patient required reinitiation of antihyperglycemic medications to control her glucose levels. Given the resolution of hypoglycemia with lenalidomide discontinuation and return of hyperglycemia after restarting the agent, it is likely that lenalidomide was the cause of the patient's hypoglycemia. Use of the Naranjo adverse drug reaction probability scale indicated a definite relationship (score of 9) between the patient's development of grade 3 hypoglycemia and lenalidomide therapy. Although this adverse drug reaction had been previously reported with lenalidomide during phase I trials in patients with solid tumors, only grade 1 or 2 hypoglycemia was reported in three patients. To our knowledge, this is the first reported case of grade 3 hypoglycemia caused by lenalidomide.

Primary Hepatic Neoplasms of Vascular Origin: Key Imaging Features and Differential Diagnoses With Radiology-Pathology Correlation

OBJECTIVE

This article describes, illustrates, and correlates imaging and pathologic features of primary vascular mesenchymal neoplasms of the liver, which arise from the vascular endothelium and perivascular epithelioid cells.

CONCLUSION

Familiarity with the spectrum of benign, malignant-potential and malignant vascular neoplasms, and nonneoplastic mimickers allows consideration in the differential diagnosis of enhancing hepatic masses. Understanding relevant pathologic features facilitates recognition of key imaging features, specifically dynamic contrast enhancement patterns on CT and MRI, which provide a useful classification system.

Surgically cured paraneoplastic hypoglycemia associated with solitary fibrous tumor of the pleura: report of two cases

Hypoglycemia is seldom seen in association with insulinomas, rare autoimmune diseases, and paraneoplastic situations. Paraneoplastic hypoglycemia is known as nonislet cell tumor‐induced hypoglycemia (NICTH). It is also known that a solitary fibrous tumor of the pleura can cause NICTH and that surgical resection is crucial to the success of NICTH treatment.

Conservative approach for a solitary fibrous tumor of the kidney

INTRODUCTION

Solitary fibrous tumor (SFT) of the kidney represents a rare neoplasm, and its malignant potential seems to be scarce. Classically, a radical nephrectomy is regarded as the treatment of choice for this condition.

CASE REPORT

We present the case of a 37-year-old male patient who underwent left robotic clampless partial nephrectomy of an SFT of the kidney. Our patient has been followed-up carefully, and at 15-month examination, he is free of recurrence. This is the second case of an SFT managed through a conservative approach.

CONCLUSIONS

In our opinion, according to tumor's dimensions, partial nephrectomy may be considered for treating small SFTs.