High False Positivity in Positron Emission Tomography is a Potential Diagnostic Pitfall in Patients with Suspected Adrenal Metastasis

Histological Validation of FDG and PSMA-Targeted PET/CT Imaging in a Rare Tracheal Adenoid Cystic Carcinoma

ABSTRACT

Adenoid cystic carcinomas are the second most common entity of tracheal malignancies, which have an overall incidence as low as only 0.2 in 100,000 persons per year. We present the case of a 64-year-old man with a histologically confirmed adenoid cystic carcinoma who sequentially underwent 18F-FDG PET/CT and 68Ga-PSMA-11 PET/CT within 1 day for staging 3 days before surgical resection of the tumor. Immunohistochemistry revealed PSMA expression of the tumor corroborating the PSMA PET findings.

Benign Adrenal Nodule Mimicking Lymphoma Differentially Diagnosed by 18F-FDG and 18F-FGln PET/CT

ABSTRACT

18F-FDG and 18F-(2S,4R)4-fluoroglutamine (18F-FGln) PET/CT were performed in a 58-year-old woman with suspected small intestinal malignancy for differential diagnosis and staging. 18F-FDG and 18F-FGln PET images showed consistent intense hypermetabolic lesion activity in part of the small intestine. Moreover, 18F-FDG/PET demonstrated a focal of increased radiotracer uptake in left adrenal lesion, which did not show abnormal activity on 18F-FGln/PET. The postoperative pathology confirmed that it was a peripheral T-cell lymphomas of the intestine, and the adrenal lesion was considered benign after continuous CT follow-up for more than 2 years.

CT-guided percutaneous core biopsy for assessment of morphologically normal adrenal glands showing high FDG uptake in patients with lung cancer

OBJECTIVE:

Increased fludeoxyglucose (FDG) uptake in morphologically normal adrenal glands on positron emission tomography-CT (PET-CT) is a diagnostic challenge with major implications on treatment. The purpose of this retrospective study was to report our experience of CT-guided percutaneous core biopsy of morphologically normal adrenal glands showing increased FDG uptake in a context of lung cancer.

METHODS:

Biopsies for non-enlarged adrenal glands showing increased FDG uptake in lung cancer patients performed at our institution from December 2014 to December 2016 were retrospectively analyzed. Six biopsies were performed in five patients during the study period. All procedures were performed with the patients in the prone position, using a posterior approach and coaxial 17-gauge needles with 18-gauge automated cutting needles. Patient characteristics, procedural details and final pathological diagnosis were analyzed, as well as the duration of hospitalization.

RESULTS:

Five of the six biopsies (83.3%) confirmed adrenal metastasis from the primary lung cancer. No complications were reported and the patients were discharged the day after the procedure.

CONCLUSION:

The high confirmation rate of metastasis and lack of complications support performing CT-guided percutaneous biopsy of non-enlarged adrenal glands showing increased FDG uptake, for optimal management in lung cancer patients.

ADVANCES IN KNOWLEDGE:

Morphologically normal adrenal glands showing high FDG uptake in patients with lung cancer are metastasis. This manuscript shows that CT-guided percutaneous biopsy should be proposed. Increased FDG uptake in morphologically normal adrenal glands may indicate metastasis.

Management of adrenal incidentalomas: European Society of Endocrinology Clinical Practice Guideline in collaboration with the European Network for the Study of Adrenal Tumors

: By definition, an adrenal incidentaloma is an asymptomatic adrenal mass detected on imaging not performed for suspected adrenal disease. In most cases, adrenal incidentalomas are nonfunctioning adrenocortical adenomas, but may also represent conditions requiring therapeutic intervention (e.g. adrenocortical carcinoma, pheochromocytoma, hormone-producing adenoma or metastasis). The purpose of this guideline is to provide clinicians with best possible evidence-based recommendations for clinical management of patients with adrenal incidentalomas based on the GRADE (Grading of Recommendations Assessment, Development and Evaluation) system. We predefined four main clinical questions crucial for the management of adrenal incidentaloma patients, addressing these four with systematic literature searches: (A) How to assess risk of malignancy?; (B) How to define and manage low-level autonomous cortisol secretion, formerly called 'subclinical' Cushing's syndrome?; (C) Who should have surgical treatment and how should it be performed?; (D) What follow-up is indicated if the adrenal incidentaloma is not surgically removed? SELECTED RECOMMENDATIONS: (i) At the time of initial detection of an adrenal mass establishing whether the mass is benign or malignant is an important aim to avoid cumbersome and expensive follow-up imaging in those with benign disease. (ii) To exclude cortisol excess, a 1mg overnight dexamethasone suppression test should be performed (applying a cut-off value of serum cortisol ≤50nmol/L (1.8µg/dL)). (iii) For patients without clinical signs of overt Cushing's syndrome but serum cortisol levels post 1mg dexamethasone >138nmol/L (>5µg/dL), we propose the term 'autonomous cortisol secretion'. (iv) All patients with '(possible) autonomous cortisol' secretion should be screened for hypertension and type 2 diabetes mellitus, to ensure these are appropriately treated. (v) Surgical treatment should be considered in an individualized approach in patients with 'autonomous cortisol secretion' who also have comorbidities that are potentially related to cortisol excess. (vi) In principle, the appropriateness of surgical intervention should be guided by the likelihood of malignancy, the presence and degree of hormone excess, age, general health and patient preference. (vii) Surgery is not usually indicated in patients with an asymptomatic, nonfunctioning unilateral adrenal mass and obvious benign features on imaging studies. We provide guidance on which surgical approach should be considered for adrenal masses with radiological findings suspicious of malignancy. Furthermore, we offer recommendations for the follow-up of patients with adrenal incidentaloma who do not undergo adrenal surgery, for those with bilateral incidentalomas, for patients with extra-adrenal malignancy and adrenal masses and for young and elderly patients with adrenal incidentalomas.

MANAGEMENT OF ENDOCRINE DISEASE: Imaging for the diagnosis of malignancy in incidentally discovered adrenal masses: a systematic review and meta-analysis

OBJECTIVE

Adrenal masses are incidentally discovered in 5% of CT scans. In 2013/2014, 81 million CT examinations were undertaken in the USA and 5 million in the UK. However, uncertainty remains around the optimal imaging approach for diagnosing malignancy. We aimed to review the evidence on the accuracy of imaging tests for differentiating malignant from benign adrenal masses.

DESIGN

A systematic review and meta-analysis was conducted.

METHODS

We searched MEDLINE, EMBASE, Cochrane CENTRAL Register of Controlled Trials, Science Citation Index, Conference Proceedings Citation Index, and ZETOC (January 1990 to August 2015). We included studies evaluating the accuracy of CT, MRI, or (18)F-fluoro-deoxyglucose (FDG)-PET compared with an adequate histological or imaging-based follow-up reference standard.

RESULTS

We identified 37 studies suitable for inclusion, after screening 5469 references and 525 full-text articles. Studies evaluated the accuracy of CT (n=16), MRI (n=15), and FDG-PET (n=9) and were generally small and at high or unclear risk of bias. Only 19 studies were eligible for meta-analysis. Limited data suggest that CT density >10HU has high sensitivity for detection of adrenal malignancy in participants with no prior indication for adrenal imaging, that is, masses with ≤10HU are unlikely to be malignant. All other estimates of test performance are based on too small numbers.

CONCLUSIONS

Despite their widespread use in routine assessment, there is insufficient evidence for the diagnostic value of individual imaging tests in distinguishing benign from malignant adrenal masses. Future research is urgently needed and should include prospective test validation studies for imaging and novel diagnostic approaches alongside detailed health economics analysis.

Adrenal incidentalomas: A guide to assessment, treatment and follow-up

Adrenal incidentalomas are clinically unsuspected lesions that are detected in adrenal glands during imaging procedures for other causes. With widespread use of imaging - both computed tomography (CT) and magnetic resonance imaging (MRI) - adrenal incidentalomas are now a common clinical problem. The two main clinical issues to be determined in this setting are the risk of malignancy and the hormonal activity of these lesions. The answers to these two questions, along with the clinical characteristics of each individual patient and co-morbidities, will guide the treatment strategy, which can vary from simple follow-up to surgical resection. The objective of this article is to present updated information on the definition, prevalence, imaging and functional features of adrenal incidentalomas and to provide a guide to their optimal assessment, treatment and follow-up. This review collected, analyzed and qualitatively re-synthesized information regarding: (1) the various clinical entities known as "adrenal incidentalomas", (2) the initial assessment of risk of malignancy, (3) the initial assessment of whether the lesion is hormonally active or non-functioning, (4) the absolute and relative indications for surgical treatment, (5) the follow-up of patients who are not deemed to need surgical treatment after initial assessment, and (6) the post-operative follow-up of patients who undergo surgical treatment. The evidence calls for clinicians to bear in mind the Hippocratian advice "ωϕελέειν ή μη βλάπτειν" ("first do no harm").

Management of suspected adrenal metastases at 2 academic medical centers

BACKGROUND

The optimal management of suspected adrenal metastases remains controversial.

METHODS

This is a retrospective bi-institutional review of 37 patients who underwent adrenalectomy for suspected adrenal metastasis between 2001 and 2014.

RESULTS

Three (8%) patients had benign adenomas on final pathology. At a median follow-up of 21 months, 7 (32%) patients were alive with no evidence of disease and 7 (32%) were alive with recurrent disease. Recurrence-free survival (RFS) was 8 months; decreased RFS was associated with positive margins and size ≥6 cm. Overall survival (OS) was 29 months; decreased OS was associated with capsular disruption. There were no differences in RFS or OS by surgical approach.

CONCLUSIONS

The favorable OS supports adrenalectomy in select patients with suspected adrenal metastases. Minimally invasive adrenalectomy is safe and effective, but the surgical approach should be based on the ability to achieve a margin-negative resection with avoidance of capsular disruption.