Adrenal myelolipoma: an unusual cause of bilateral highly 18F-FDG-avid adrenal masses

[Difficulty with differential diagnosis on adrenal lesions in congenital adrenal cortex dysfunction: a series of clinical cases]

Congenital adrenal hyperplasia (CAH) encompasses a group of autosomal recessive disorders characterized by defects in enzymes critical for steroidogenesis, with 21-hydroxylase deficiency due to mutations in the CYP21A2 gene being the most prevalent form.Since the introduction of replacement therapy and neonatal screening programs in the 1950s, there has been a significant increase in survival rates among newborns diagnosed with CAH. However, despite these advancements, mortality associated with this condition remains disproportionately high. Achieving optimal therapeutic compensation through medication remains a complex challenge, contributing to a range of long-term complications. These complications stem from both the underlying disease and its treatment, impacting key physiological functions, including metabolism, growth and development, cardiovascular health, and fertility. These multifaceted outcomes underscore the need for ongoing research and the refinement of therapeutic approaches to better manage this intricate condition. This article presents a series of four clinical cases of CAH characterized by the absence of sustained compensation for glucoand mineralocorticoid deficiencies. These cases were further complicated by the development of large adrenal masses and ectopic testicular adrenal rest tissue (TART), emphasizing the challenges in achieving long-term disease management.

Right Adrenocortical Carcinoma Coexisting With Left Adrenal Sarcomatoid Carcinoma on FDG PET/CT

ABSTRACT

Bilateral adrenal glands synchronously involved by different types of pathologies are uncommon. An 80-year-old man underwent FDG PET/CT to evaluate bilateral adrenal masses, which were initially discovered by ultrasonography and confirmed by MRI. The images demonstrated elevated FDG activity in both lesions, which were subsequently diagnosed as concurrent right adrenocortical carcinoma and left adrenal sarcomatoid carcinoma respectively by histopathological examination.

Contemporary imaging of incidentally discovered adrenal masses

Adrenal lesions are routinely encountered incidentally in clinical practice. Although most of these lesions are benign, malignancy needs to be excluded. Therefore, the initial clinical workup is to exclude aggressive characteristics suggesting malignancy and to identify characteristics predictive of the most common benign lesion, an adrenal adenoma. Predicting a benign adenoma using a variety of imaging modalities has been widely studied using unenhanced computed tomography (CT), contrast enhanced CT, and magnetic resonance (MR) imaging. This review article describes the currently used imaging protocols and clinical interpretation criteria of common adrenal lesions. An adenoma can be predicted if a homogenous soft tissue adrenal mass demonstrates low attenuation (upper threshold value of 10 Hounsfield Units) on unenhanced CT, demonstrates an absolute enhancement washout of ≥ 60% and/or relative enhancement washout of ≥ 40% on adrenal washout contrast enhanced CT, or demonstrates signal loss in opposed-phased MR imaging. If an adrenal adenoma cannot be predicted based upon these criteria, the lesion should be evaluated for other imaging characteristics that suggest a specific pathology, such as an adrenal cyst or myelolipoma. Although nonspecific and with limitations, 18F-fluorodeoxyglucose (FDG) PET/CT has a potential role for differentiating benign from malignant lesions based upon the amount of radiopharmaceutical uptake with malignant lesions generally having greater uptake. If clinical and/or hormonal screening suggests a pheochromocytoma, consideration can be given to 18F-dihydroxyphenylalanine (DOPA) or 123I-metaiodobenzylguanidine (MIBG) in addition to CT and MR. Finally, this review proposes a diagnostic work-up strategy for routine use in clinical practice.

Vasovagal-related stress immediately before FDG injection may increase bilateral adrenal FDG uptake

OBJECTIVE

To evaluate the relationship between vasovagal-related stress on positron emission tomography (PET)/CT and adrenal fludeoxyglucose (FDG) uptake.

METHODS

We reviewed the medical records of 1358 consecutive patients who underwent FDG PET/CT examinations and selected those who presented with vasovagal-related symptoms and acute hypotension immediately before FDG injection (vasovagal reflex group). Patients who underwent FDG PET/CT examinations on the same days as the vasovagal reflex group without new complaints or any adrenal lesion were used as controls. We evaluated adrenal FDG uptake visually and by means of adrenal maximum standardized uptake value (SUV(max)) and adrenal/liver (A/L) SUV(max) ratio. Next, we reviewed the FDG PET/CT images of the same 1358 patients and selected the cases presenting with bilateral avid FDG uptake.

RESULTS

4 patients were included in the vasovagal reflex group, and all of them showed bilateral avid adrenal FDG uptake visually, while 19 patients in the control group did not. The mean adrenal SUV(max) and the mean A/L SUV(max) ratio were significantly higher in the vasovagal reflex group than in the control group (p < 0.001). 10 (0.74%) patients, including 4 patients from the vasovagal reflex group, showed bilateral avid FDG uptake with normal adrenal configuration on CT.

CONCLUSION

Vasovagal-related stress immediately before FDG injection may increase bilateral adrenal FDG uptake.

ADVANCES IN KNOWLEDGE

Vasovagal-related stress may be included in the differential diagnosis of the cause of bilateral avid adrenal FDG uptake.

FDG-PET/CT and FLT-PET/CT for differentiating between lipid-poor benign and malignant adrenal tumours

OBJECTIVE

To compare F-18-fluorodeoxyglucose (FDG) and F-18-fluorothymidine (FLT) PET/CT examinations for differentiating between benign and malignant adrenal tumours.

METHODS

Thirty lipid-poor benign and 11 malignant tumours of 40 patients were included. FDG- and FLT-based indices including visual score, maximum standardized uptake value (SUVmax) and FDG adrenal lesion/liver SUVmax (A/L SUVmax) or FLT adrenal lesion/back muscle SUVmax (A/B SUVmax) ratio were compared between benign and malignant tumours using the Mann-Whitney's U or Wilcoxon signed-rank test, and their diagnostic performances were evaluated by means of the area under the curve (AUC) values derived from the receiver operating characteristic analysis.

RESULTS

All indices were significantly higher in malignant than benign tumours on both images (p < 0.05 each). On FDG-PET/CT, the sensitivity, specificity, and accuracy were 91 %, 63 % and 71 % for visual score, 91 %, 67 % and 73 % for SUVmax, and 100 %, 70 % and 78 % for A/L SUVmax ratio, respectively. On FLT-PET/CT, they were 100 %, 97 % and 98 % for visual score, SUVmax and A/B SUVmax ratio, respectively. All FLT indices were significantly higher than those of FDG in AUC (p < 0.05 each).

CONCLUSION

FLT-PET/CT may be superior to FDG-PET/CT in differentiating lipid-poor benign from malignant adrenal tumours because of higher specificity and accuracy.

KEY POINTS

• All FDG indices were significantly higher in malignant than in benign tumours. • All FLT indices were significantly higher in malignant than in benign tumours. • All FLT indices were significantly higher than those of FDG in AUC.

Adrenal myelolipoma: Controversies in its management

Adrenal myelolipomas (AMLs) are rare, benign neoplasms of the adrenal gland with varied clinical presentations. The rarity of these tumors precludes any case-controlled or randomized study into their management. The available literature is limited to case reports and short series from referral centers. This review is an effort to put the available literature into perspective such that clinical decision making can be done with some clarity. The PubMed and Cochrane databases were searched with key words Adrenal Myelolipoma, Adrenal Incidentaloma (AI) and Adrenal Collision Tumor (ACT). From over 1300 search results, 547 relevant publications dating from 1954 to 2014 were reviewed. Details of about 1231 AMLs in the indexed literature were analyzed. Increasing usage of imaging studies has significantly increased the discovery of AMLs. Although AMLs are benign tumors, those measuring larger than 6 cm are prone to rupture and hemorrhage. Thorough endocrine work-up may benefit a selected group of patients, especially those who are hypertensive, diabetic/pre-diabetic, young patients (<50 years) and those with bilateral AML. Regular observation is needed for AML patients who are being treated non-operatively, as many of them may require surgery during follow-up. Although the AACE/AAES guidelines for AI (2009) exclude AML from mandatory metabolic work-up for a newly discovered AI, we feel that a significant number of patients with AML would benefit from metabolic work-up. In the literature, endocrine dysfunction in AML is 7% as compared with 11% in AI. Endocrine dysfunction in AML is probably underdiagnosed.

Bilateral adrenal myelolipomas in a woman with chronic anticoagulation, postmenopausal uterine bleeding, primary hyperparathyroidism and hyperthyroidism

Adrenal myelolipomas are rare, usually benign unilateral tumors. Their management has controversially been discussed. The authors here present a 53-year-old African American female Jehovah's witness with postmenopausal uterine bleeding on chronic anticoagulation and episodic right flank pain who was found to have bilateral myelolipomas in addition to primary hyperparathyroidism. In collaboration with gynecology, midline laparotomy was performed to remove uterus and both ovaries in addition to the right adrenal gland for a 62 × 79 mm myelolipoma. An open biopsy of the left adrenal mass measuring 42 × 43 mm revealed myelolipoma and ruled out malignancy. Pathology confirmed bilateral myelolipomas, endometrial polyps, and leiomyomata uteri. After an uneventful recovery, the patient then underwent a right inferior parathyroidectomy for parathyroid adenoma. This case illustrates the challenges in deciding when to surgically intervene for bilateral adrenal myelolipoma and, for the first time, associates various other endocrinopathies, although no known endocrine neoplasia syndrome variant was present.