Beyond the three P's: adrenal involvement in MEN1

Adrenal lesions (ALs) are often detected in patients with multiple endocrine neoplasia type 1 (MEN1). However, they are not well described in MEN1, making their clinical management unclear. This study examined the prevalence and outcomes of ALs found in MEN1. We performed a retrospective chart review of patients diagnosed with MEN1 from 1990 to 2021. ALs were diagnosed using abdominal or thoracic imaging and classified as being unilateral or bilateral, having single or multiple nodules, and as having diffuse enlargement or not. Measurable nodular lesions were analyzed for their size and growth over time. Patients' clinical and radiographic characteristics were collected. We identified 382 patients with MEN1, 89 (23.3%) of whom had ALs. The mean age at detection was 47 ± 11.9 years. We documented 101 measurable nodular lesions (mean size, 17.5 mm; range, 3-123 mm). Twenty-seven nodules (26.7%) were smaller than 1 cm. Watchful waiting was indicated in 79 (78.2%) patients, of whom 28 (35.4%) had growing lesions. Functional lesions were diagnosed in 6 (15.8%) of 38 that had functional work-up (diagnoses: pheochromocytoma (n = 2), adrenocorticotropic hormone-dependent hypercortisolism (n = 2), hyperandrogenism (n = 1), hyperaldosteronism (n = 1)); surgery was indicated for 5 (83.3%; n = 12 nodules), 2 of whom had bilateral, diffuse adrenal enlargement. Two patients were diagnosed with adrenocortical carcinoma and two with neoplasms of uncertain malignant potential. Radiographic or clinical progression of ALs is uncommon. Malignancy should be suspected on the basis of a lesion's growth rate and size. A baseline hormonal work-up is recommended, and no further biochemical work-up is suggested when the initial assessment shows nonfunctioning lesions.

Allelic Variants of ARMC5 in Patients With Adrenal Incidentalomas and in Patients With Cushing's Syndrome Associated With Bilateral Adrenal Nodules

Objective: Germline ARMC5 mutations are considered to be the main genetic cause of primary macronodular adrenal hyperplasia (PMAH). PMAH is associated with high variability of cortisol secretion caused from subclinical hypercortisolism to overt Cushing's syndrome (CS), in general due to bilateral adrenal nodules and rarely could also be due to non-synchronic unilateral adrenal nodules. The frequency of adrenal incidentalomas (AI) associated with PMAH is unknown. This study evaluated germline allelic variants of ARMC5 in patients with bilateral and unilateral AI and in patients with overt CS associated with bilateral adrenal nodules. Methods: We performed a retrospective multicenter study involving 123 patients with AI (64 bilateral; 59 unilateral). We also analyzed 20 patients with ACTH pituitary independent overt CS associated with bilateral adrenal nodules. All patients underwent germline genotyping analysis of ARMC5; abdominal CT and were classified as normal, possible or autonomous cortisol secretion, according to the low doses of dexamethasone suppression test. Results: We identified only one pathogenic allelic variant among the patients with bilateral AI. We did not identify any pathogenic allelic variants of ARMC5 in patients with unilateral AI. Thirteen out of 20 patients (65%) with overt CS and bilateral adrenal nodules were carriers of pathogenic germline ARMC5 allelic variants, all previously described. The germline ARMC5 mutation was observed in only one patient with bilateral AI; it was associated with autonomous cortisol secretion and showed to be a familial form. Conclusion: The rarity of germline ARMC5 mutations in AI points to other molecular mechanisms involved in this common adrenal disorder and should be investigated. In contrast, patients with overt Cushing's syndrome and bilateral adrenal nodules had the presence of ARMC5 mutations that were with high prevalence and similar to the literature. Therefore, we recommend the genetic analysis of ARMC5 for patients with established Cushing's syndrome and bilateral adrenal nodules rather than patients with unilateral AI.

Can Texture Analysis Be Used to Distinguish Benign From Malignant Adrenal Nodules on Unenhanced CT, Contrast-Enhanced CT, or In-Phase and Opposed-Phase MRI?

OBJECTIVE

The purpose of this study is to determine whether second-order texture analysis can be used to distinguish lipid-poor adenomas from malignant adrenal nodules on unenhanced CT, contrast-enhanced CT (CECT), and chemical-shift MRI.

MATERIALS AND METHODS

In this retrospective study, 23 adrenal nodules (15 lipid-poor adenomas and eight adrenal malignancies) in 20 patients (nine female patients and 11 male patients; mean age, 59 years [range, 15-80 years]) were assessed. All patients underwent unenhanced CT, CECT, and chemical-shift MRI. Twenty-one second-order texture features from the gray-level cooccurrence matrix and gray-level run-length matrix were calculated in 3D. The mean values for 21 texture features and four imaging features (lesion size, unenhanced CT attenuation, CECT attenuation, and signal intensity index) were compared using a t test. The diagnostic performance of texture analysis versus imaging features was also compared using AUC values. Multivariate logistic regression models to predict malignancy were constructed for texture analysis and imaging features.

RESULTS

Lesion size, unenhanced CT attenuation, and the signal intensity index showed significant differences between benign and malignant adrenal nodules. No significant difference was seen for CECT attenuation. Eighteen of 21 CECT texture features and nine of 21 unenhanced CT texture features revealed significant differences between benign and malignant adrenal nodules. CECT texture features (mean AUC value, 0.80) performed better than CECT attenuation (mean AUC value, 0.60). Multivariate logistic regression models showed that CECT texture features, chemical-shift MRI texture features, and imaging features were predictive of malignancy.

CONCLUSION

Texture analysis has a potential role in distinguishing benign from malignant adrenal nodules on CECT and may decrease the need for additional imaging studies in the workup of incidentally discovered adrenal nodules.