Successful application of technetium-99m-labeled octreotide acetate scintigraphy in the detection of ectopic adrenocorticotropin-producing bronchial carcinoid lung tumor: a case report

A review of pediatric neuroendocrine tumors, their detection, and treatment by radioisotopes

Neuroendocrine tumors (NETs) are rare in childhood. Neuroblastoma is the most common pediatric extracranial solid tumor, occurring >90% in children younger than 5 years of age. Pheochromocytoma and paraganglioma are rare NETs, causing hypertension in 0.5-2% of hypertensive children. Gastroenteropancreatic NETs can occur in children and are classified into carcinoids and pancreatic tumors. Nuclear medicine procedures have an essential role both in the diagnosis and treatment of NETs. Metaiodobenzylguanidine (MIBG) labeled with radioiodine has a well-established role in diagnosis as well as therapeutic management of the neuroblastoma group of diseases. During recent decades, establishing the abundant expression of somatostatin receptors by NETs first led to scintigraphy with somatostatin analogs (i.e. Tc/In-octreotide) and, later, with the emergence of positron-emitting labeled agents (i.e. Ga-DOTATATE/DOTATOC/DOTANOC) PET scans with significantly higher detection efficiency became available. Therapy with somatostatin analogs labeled with beta emitters such as Lu-177 and Y-90, known as peptide receptor radionuclide therapy, is a promising new option in the management of patients with inoperable or metastasized NETs. In this article, pediatric NETs are briefly reviewed and the role of radioactive agents in the detection and treatment of these tumors is discussed.

Production and Clinical Applications of Radiopharmaceuticals and Medical Radioisotopes in Iran

During past 3 decades, nuclear medicine has flourished as vibrant and independent medical specialty in Iran. Since that time, more than 200 nuclear physicians have been trained and now practicing in nearly 158 centers throughout the country. In the same period, Tc-99m generators and variety of cold kits for conventional nuclear medicine were locally produced for the first time. Local production has continued to mature in robust manner while fulfilling international standards. To meet the ever-growing demand at the national level and with international achievements in mind, work for production of other Tc-99m-based peptides such as ubiquicidin, bombesin, octreotide, and more recently a kit formulation for Tc-99m TRODAT-1 for clinical use was introduced. Other than the Tehran Research Reactor, the oldest facility active in production of medical radioisotopes, there is one commercial and three hospital-based cyclotrons currently operational in the country. I-131 has been one of the oldest radioisotope produced in Iran and traditionally used for treatment of thyrotoxicosis and differentiated thyroid carcinoma. Since 2009, (131)I-meta-iodobenzylguanidine has been locally available for diagnostic applications. Gallium-67 citrate, thallium-201 thallous chloride, and Indium-111 in the form of DTPA and Oxine are among the early cyclotron-produced tracers available in Iran for about 2 decades. Rb-81/Kr-81m generator has been available for pulmonary ventilation studies since 1996. Experimental production of PET radiopharmaceuticals began in 1998. This work has culminated with development and optimization of the high-scale production line of (18)F-FDG shortly after installation of PET/CT scanner in 2012. In the field of therapy, other than the use of old timers such as I-131 and different forms of P-32, there has been quite a significant advancement in production and application of therapeutic radiopharmaceuticals in recent years. Application of (131)I-meta-iodobenzylguanidine for treatment of neuroblastoma, pheochromocytoma, and other neuroendocrine tumors has been steadily increasing in major academic university hospitals. Also (153)Sm-EDTMP, (177)Lu-EDTMP, (90)Y-citrate, (90)Y-hydroxyapatite colloid, (188/186)Re-sulfur colloid, and (188/186)Re-HEDP have been locally developed and now routinely available for bone pain palliation and radiosynovectomy. Cu-64 has been available to the nuclear medicine community for some time. With recent reports in diagnostic and therapeutic applications of this agent especially in the field of oncology, we anticipate an expansion in production and availability. The initiation of the production line for gallium-68 generator is one of the latest exciting developments. We are proud that Iran would be joining the club of few nations with production lines for this type of generator. There are also quite a number of SPECT and PET tracers at research and preclinical stage of development preliminarily introduced for possible future clinical applications. Availability of fluorine-18 tracers and gallium-68 generators would no doubt allow rapid dissemination of PET/CT practices in various parts of our large country even far from a cyclotron facility. Also, local production and availability of therapeutic radiopharmaceuticals are going to open exciting horizons in the field of nuclear medicine therapy. Given the available manpower, local infrastructure of SPECT imaging, and rapidly growing population, the production of Tc-99m generators and cold kit would continue to flourish in Iran.

Uptake Difference by Somatostatin Receptors in a Patient with Neuroendocrine Tumor: 99mTc-Octreotide Uptake in the Lung without Uptake in Liver Lesions

The diagnostic value of somatostatin receptor scintigraphy (SRS) in detecting tumors has been assessed in a number of studies. We present a 30-year-old female with a history of eight months cough and left shoulder pain. Radiologic evaluation showed pulmonary mass and hepatic lesions, which were pathologically diagnosed as neuroendocrine carcinoma. 99mTc-octreotide scan demonstrated that the pulmonary lesion was positive for somatostatin receptor (SSTR), while the liver metastases were SSTR negative. The present case highlights the significance of a differential uptake pattern by somatostatin receptors in SRS in patients with neuroendocrine tumors.

Conventional and Nuclear Medicine Imaging in Ectopic Cushing's Syndrome: A Systematic Review

CONTEXT

Ectopic Cushing's Syndrome (ECS) can be a diagnostic challenge with the hormonal source difficult to find. This study analyzes the accuracy of imaging studies in ECS localization.

EVIDENCE ACQUISITION

Systematic review of medical literature for ECS case series providing individual patient data on at least one conventional imaging technique (computed tomography [CT]/magnetic resonance imaging) and one of the following: 111In-pentetreotide (OCT), 131I/123I-metaiodobenzylguanidine, 18Ffluoro-2-deoxyglucose-positron emission tomography (FDG-PET), 18F-fluorodopa-PET (F-DOPA-PET), 68Ga- DOTATATE-PET/CT or 68Ga-DOTATOC-PET/CT scan (68Gallium-SSTR-PET/CT).

EVIDENCE SUMMARY

The analysis comprised 231 patients (females, 50.2%; age, 42.617 y). Overall, 52.4%(121/231) had "overt" ECS,18.6% had "occult" ECS, and 29% had "covert" ECS. Tumors were located in the lung (55.3%), mediastinum-thymus (7.9%), pancreas (8.5%), adrenal glands (6.4%), gastrointestinal tract (5.4%), thyroid (3.7%), and other sites (12.8%), and primary tumors were mostly bronchial neuroendocrine tumors (NETs) (54.8%), pancreatic NETs (8%), mediastinum-thymus NETs (6.9%), gastrointestinal NETs (5.3%), pheochromocytoma (6.4%), neuroblastoma (3.2%), and medullary thyroid carcinoma (3.2%). Tumors were localized byCTin66.2%(137/207), magnetic resonance imaging in 51.5% (53/103), OCT in 48.9% (84/172), FDG-PET in 51.7% (46/89), F-DOPAPET in 57.1% (12/21), 131/123I-metaiodobenzylguanidine in 30.8% (4/13), and 68Gallium-SSTRPET/CT in 81.8% (18/22) of cases. Molecular imaging discovered 79.1% (53/67) of tumors unidentified by conventional radiology, with OCT the most commonly used, revealing the tumor in 64%, followed by FDG-PET in 59.4%. F-DOPA-PET was used in only seven covert cases (sensitivity, 85.7%). Notably, 68Gallium-SSTR-PET/CT had 100% sensitivity among covert cases.

CONCLUSIONS

Nuclear medicine improves the sensitivity of conventional radiology when tumor site identification is problematic. OCT offers a good availability/reliability ratio, and FDG-PET was proven useful. 68Gallium-SSTR-PET/CT use was infrequent, despite offering the highest sensitivity.

Anesthetic considerations on adrenal gland surgery

Adrenal gland surgery needs a multidisciplinary team including endocrinologist, radiologist, anesthesiologist, and surgeon. The indications for adrenal gland surgery include hormonal secreting and non-hormonal secreting tumors. Adrenal hormonal secreting tumors present to the anesthesiologist unique challenges requiring good preoperative evaluation, perioperative hemodynamic control, corrections of all electrolytes and metabolic abnormalities, a detailed and careful anesthetic strategy, overall knowledge about the specific diseases, control and maintaining of postoperative adrenal function, and finally a good collaboration with other involved colleagues. This review will focus on the endocrine issues, as well as on the above-mentioned aspects of anesthetic management during hormone secreting adrenal gland tumor resection.

The value of somatostatin receptor imaging with In-111 Octreotide and/or Ga-68 DOTATATE in localizing Ectopic ACTH producing tumors

OBJECTIVE

We aimed to evaluate the value of somatostatin receptor imaging (SRI) with In-111 octreotide and Ga-68 DOTATATE in localizing ectopic ACTH producing tumors.

METHODS

Nineteen patients who had In-111 octreotide somatostatin receptor scintigraphy (SRS) and/or Ga-68 DOTATATE PET-CT to localize ectopic ACTH producing tumors between the years 2000 and 2012 were included retrospectively in our study. The results of SRI were compared with clinical onset, radiological findings and surgical data of the patients.

RESULTS

Sixteen In-111 octreotide SRS and five Ga-68 DOTATATE PET-CT were performed in 19 patients. In eight out of 19 patients, ectopic ACTH secretion site could be detected. In five patients, SRS showed pathologic uptake. In four of these patients, surgery revealed pulmonary carcinoid tumors and in one patient pancreatic neuroendocrine tumor. In one patient, Ga-68 DOTATATE PET-CT revealed pathologic uptake in lung nodule which came out to be pulmonary carcinoid tumor. In another patient who had resection of metastases of atypical carcinoid tumor prior to scans, new metastatic foci were detected both with SRS and Ga-68 DOTATATE PET-CT imaging. In one patient, although SRS was negative, CT which was performed three years later showed a lung nodule diagnosed as pulmonary carcinoid tumor. In 11 patients, ectopic ACTH secretion site could not be detected. In 10 of those patients, scintigraphic and radiological imaging did not show any lesions and in one patient, Ga-68 DOTATATE PET-CT was false positive.

CONCLUSION

SRI has a complementary role with radiological imaging in localizing ectopic ACTH secretion sites. PET-CT imaging with Ga-68 peptide conjugates is a promising new modality for this indication.

CONFLICT OF INTEREST

None declared.

Atypical or typical adrenocorticotropic hormone-producing pulmonary carcinoids and the usefulness of 11C-5-hydroxytryptophan positron emission tomography: two case reports

Introduction

Pulmonary carcinoids associated with ectopic adrenocorticotropic hormone secretion have a good prognosis if histological examination shows typical pulmonary carcinoid and low proliferation, whereas a poor outcome is linked to atypical pulmonary carcinoid and high proliferation. Here we describe the diagnostic challenges to find the tumor in Cushing’s syndrome secondary to ectopic adrenocorticotropic hormone secretion in two cases with an atypical and a typical pulmonary carcinoid, respectively.

Case presentation

A 63-year-old Caucasian woman presented with aggressive clinical features related to Cushing’s syndrome, having very high levels of urinary cortisol and circulating adrenocorticotropic hormone and cortisol. Magnetic resonance imaging showed no pituitary tumor, and bilateral inferior petrosal sinus sampling revealed no central peripheral ratio of adrenocorticotropic hormone. Computed tomography and ¹¹¹Indium-pentetreoide somatostatin receptor scintigraphy could not visualize any ectopic tumor. The patient was referred for an ¹¹C-5-hydroxytryptophan positron emission tomography, and a small 8mm nodule in her left lung was found. The tumor was removed via a lateral thoracic incision and wedge excision. The histological examination showed an atypical carcinoid with Ki-67 index of 9 to 10%, and an additional lobectomy was performed.

The second patient, a 22-year-old Caucasian man, also presented with aggressive Cushing’s syndrome, with very high urinary cortisol levels and increased circulating cortisol as well as adrenocorticotropic hormone levels. A magnetic resonance imaging scan of the pituitary showed no tumor, whereas a 12×9×14mm tumor was detected in the right lung on the primary computed tomography scan and no further investigation was performed. The tumor was removed via a lateral thoracic incision and wedge excision. A typical carcinoid with Ki-67 index of 1 to 2% was found and no further surgery was performed.

After surgical removal, the biochemical disturbances resolved and significant clinical improvement were achieved in both patients after 24 months of follow up.

Conclusions

Diagnostic evaluation time is limited due to the aggressive course in ectopic adrenocorticotropic hormone-dependent Cushing’s syndrome. We suggest that ¹¹C-5-hydroxytryptophan positron emission tomography could be considered early as a secondary diagnostic tool when primary computed tomography and/or magnetic resonance imaging scans fail to show any tumor.

Cushing's surgery: Role of the anesthesiologist

Cushing's syndrome is a clinical situation, caused by excessive glucocorticoid level, resulting in several features such as central obesity, supraclavicular fat, "moon face," "buffalo hump," hyperglycemia, metabolic alkalosis, hypokalemia, poor wound healing, easy bruising, hypertension, proximal muscle weakness, thin extremities, skin thinning, menstrual irregularities, and purple striae. In the perioperative period, the anesthesiologist must deal with difficult ventilation and intubation, hemodynamic disturbances, volume overload and hypokalemia, glucose intolerance, and diabetes, maintaining the blood cortisol level and preventing the glucocorticoid deficiency. This syndrome is quite rare and its features make these patients very difficult to the anesthesiologist.

Failure of functional imaging with gallium-68-DOTA-D-Phe1-Tyr3-octreotide positron emission tomography to localize the site of ectopic adrenocorticotropic hormone secretion: a case report

Introduction

The diagnostic efficacy of biochemical and imaging modalities for investigating the causes of Cushing's syndrome are limited. We report a case demonstrating the limitations of these modalities, especially the inability of functional imaging to help localize the site of ectopic adrenocorticotropic hormone secretion.

Case presentation

A 37-year-old Arabian woman presented with 12 months of progressive Cushing's syndrome-like symptoms. Biochemical evaluation confirmed adrenocorticotropic hormone -dependent Cushing's syndrome. However, the anatomical site of her excess adrenocorticotropic hormone secretion was not clearly delineated by further investigations. Magnetic resonance imaging of our patient's pituitary gland failed to demonstrate the presence of an adenoma. Spiral computed tomography of her chest only revealed the presence of a non-specific 7 mm lesion in her left inferobasal lung segment. Functional imaging, including a positron emission tomography scan using 18-fluorodeoxyglucose and gallium-68-DOTA-D-Phe1-Tyr3-octreotide, also failed to show increased metabolic activity in the lung lesion or in her pituitary gland. Our patient was commenced on medical treatment with ketoconazole and metyrapone to control the clinical features associated with her excess cortisol secretion. Despite initial normalization of her urinary free cortisol excretion rate, levels began to rise eight months after commencement of medical treatment. Repeated imaging of her pituitary gland, chest and pelvis again failed to clearly localize a source of her excess adrenocorticotropic hormone secretion. The bronchial nodule was stable in size on serial imaging and repeatedly reported as having a nonspecific appearance of a small granuloma or lymph node. We re-explored the treatment options and endorsed our patient's favored choice of resection of the bronchial nodule, especially given that her symptoms of cortisol excess were difficult to control and refractory. Subsequently, our patient had the bronchial nodule resected. The histological appearance of the lesion was consistent with that of a carcinoid tumor and immunohistochemical analysis revealed that the tumor stained strongly positive for adrenocorticotropic hormone. Furthermore, removal of the lung lesion resulted in a normalization of our patient's 24-hour urinary free cortisol excretion rate and resolution of her symptoms and signs of hypercortisolemia.

Conclusion

This case report demonstrates the complexities and challenges in diagnosing the causes of adrenocorticotropic hormone -dependent Cushing's syndrome. Functional imaging may not always localize the site of ectopic adrenocorticotropic hormone secretion.

Cushing syndrome and the anesthesiologist, two case reports

Cushing's syndrome (CS) is associated with reduced life quality and increased mortality, mostly due to cardiovascular disease. The features of this syndrome are central obesity, moon facies, facial plethora, supraclavicular fat pads, buffalo hump, and purple striae. Other complications include hyperglycemia, hypertension, proximal muscle weakness, skin thinning, menstrual irregularities, amenorrhea and osteopenia. These make perioperative and anesthetic management difficult and present a challenge to the operating team, especially the anaesthesiologist. In this paper, we present two such cases of CS, which were treated with adrenalectomy. We aim to highlight the special care and precautions that need to be taken while administering anesthesia, and in the post operatory period. Anaesthesia induction in the two cases of CS was done prior to the adrenalectomy procedure and special pre and post operative care was taken. Continuous intra operative monitoring of vitals and checking for the stability of the haemodynamics was performed. With adequate care and using advanced anesthetic techniques, the patients showed uneventful post operative recovery. Though the anesthetic management of patients with CS is difficult, desired results can be achieved with continuous monitoring and special precautions.