Background

Adrenal lipid-poor adenomas (LPA) are defined by high unenhanced density (≥ 10 HU), and absolute and relative contrast medium washout > 60% and > 40%, respectively, at computerized tomography (CT). To date, no thorough histopathological characterization has been performed in those frequent lesions (one-third of adrenal adenomas). Our aim was to analyze the histopathological characteristics of adrenal LPA.

Methods

Patients with LPA (n = 57) were selected among consecutive subjects referred for an adrenal incidentaloma or ACTH-independent Cushing syndrome. FluoroDeoxyGlucose-Positron Emission Tomography (FDG-PET) was performed in 37 patients. In patients treated by adrenalectomy (n = 17), Weiss score and Lin–Weiss–Bisceglia score (in tumors composed entirely or predominantly of oncocytes) were calculated.

Results

Radiological parameters did not differ among patients with ACTH-independent Cushing syndrome (n = 6) and those with adrenal incidentalomas associated with primary aldosteronism (n = 2), autonomous cortisol secretion (n = 14), or non-functioning (n = 35). Patients treated by adrenalectomy had larger tumors (28.9 ± 11.2 vs 17.3 ± 8.4 mm, P < 0.001), higher CT unenhanced density (29.1 ± 11.0 vs 23.1 ± 9.0 HU, P = 0.043), and FDG-PET adrenal uptake (9.0 ± 6.4 vs 4.4 ± 2.3 SUV, P = 0.003) than non-operated ones. Oncocytic features > 75% of the tumor were detected in 12/17 cases (70.6%). Five of those showed borderline-malignant histopathological characteristics by Lin–Weiss–Bisceglia score. Among remaining non-oncocytic tumors, 1/5 had a Weiss score ≥ 3. Overall, 6/17 tumors (35.3%) had borderline-malignant potential. Radiological parameters were similar between patients with benign and borderline-malignant tumors.

Conclusions

Adrenal LPA are a heterogeneous group of tumors, mostly composed of oncocytomas. Up to 1/3 of those tumors may have a borderline-malignant potential at histopathology.

中文翻译：

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放射学确定的贫脂性肾上腺腺瘤：组织病理学特征。

背景

肾上腺脂质不足性腺瘤（LPA）的定义为：高未增强密度（≥10 HU），以及在计算机断层扫描（CT）时绝对和相对造影剂的洗脱率分别> 60％和> 40％。迄今为止，尚未对那些频繁的病变（三分之一的肾上腺腺瘤）进行彻底的组织病理学表征。我们的目的是分析肾上腺LPA的组织病理学特征。

方法

LPA患者（n  = 57）选自肾上腺偶瘤或不依赖ACTH的库欣综合征的连续受试者。氟脱氧葡萄糖正电子发射断层扫描（FDG-PET）在37例患者中进行。在接受肾上腺切除术治疗的患者中（n  = 17），计算了Weiss评分和Lin–Weiss–Bisceglia评分（在全部或主要由肿瘤细胞组成的肿瘤中）。

结果

放射参数没有患者ACTH无关的库欣综合征（之间不同Ñ  = 6）和那些具有肾上腺偶发原发性醛固酮增多症（相关Ñ  = 2），自主皮质醇分泌（Ñ  = 14），或无功能（Ñ  = 35 ）。肾上腺切除术治疗的患者肿瘤更大（28.9±11.2 vs 17.3±8.4 mm，P <0.001），CT未增强密度（29.1±11.0 vs 23.1±9.0 HU，P  = 0.043）和FDG-PET肾上腺摄取（9.0± 6.4和4.4±2.3 SUV，P = 0.003）。在12/17例中检出的肿瘤细胞特征>肿瘤的75％（70.6％）。通过Lin–Weiss–Bisceglia评分，其中五项显示了边缘恶性的组织病理学特征。在其余的非包虫性肿瘤中，有1/5的Weiss评分≥3。总体而言，有6/17肿瘤（35.3％）具有临界恶性潜能。良性和边缘性恶性肿瘤患者的放射学参数相似。

结论

肾上腺LPA是一组异质性肿瘤，主要由肿瘤细胞瘤组成。这些肿瘤中，多达1/3可能在组织病理学上具有边缘性恶性潜能。