RESEARCH
Clinical analysis of adrenal lesions larger than 5 cm in diameter (an analysis of 251 cases)
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Zongzong Zhang1+, Lina Wang1+, Jing Chen2+, Xiunan Li1+, Dikuan Liu1, Tianyu Cao1, Xuehan Yang1, Hongwei Huang1, Xuejian Wang1, Xishuang Song1, Deyong Yang1*( and Jianbo Wang1*
Abstract
Background: To describe the pathological distribution, imaging manifestations, and surgical managements and prognosis of large adrenal tumors (LATs) ≥ 5 cm
Methods: A total of 251 patients with LATs were analyzed on the basis of pathological or clinical diagnosis. Regarding surgery, open adrenalectomy was performed on 89 patients, and laparoscopic adrenalectomy was performed on 89 patients. Thirty-two patients with bilateral tumors were analyzed in terms of clinical characteristics. The survival rate was determined for 43 patients with adrenal metastases and 29 patients with primary adrenal malignancies. The CT characteristics including tumor diameter, shape, edge, heterogeneity, necrosis, calcification, pre-contrast attenuation, and contrast attenuation were analyzed for 117 patients.
Results: The majority of LATs were still benign, but they had a higher probability to be malignant. Benign LATs made up 68.13% of all cases, mainly adrenal cysts (19.52%), pheochromocytoma (18.73%), benign adenoma (16.73%), and myelolipoma (7.17%). Malignant LATs accounted for 28.69% of cases, mainly including adrenocortical carcinoma (8.76%) and metastases (17.13%). Laparoscopic surgery was found to involve less trauma than open surgery. It was also safer and postoperative recovery was faster, but it had drawbacks and could not completely replace open surgery. CT features had obvious specificity for the diagnosis of benign and malignant tumors. For example, benign adenomas had a smaller pre-contrast (< 10 Hu) whereas malignant adrenal tumors had, on the contrary, higher attenuation. Regarding adrenal malignant carcinoma, adrenal primary malignant tumors showed a better prognosis than adrenal metastases (mean survival of 19.17 months vs 9.49 months). Primary adrenal cortical carcinoma without metastasis had a better prognosis than primary adrenal cortical carcinoma metastasis (mean survival of 23.71 months vs 12.75 months), and adrenal solitary metastasis had a better prognosis than general multiple metastatic carcinoma (mean survival of 14.95 months vs 5.17 months).
Conclusion: LATs were more likely to be benign; however, they still had a high probability of being a malignant tumor. Understanding the clinicopathological characteristics of LATs can facilitate selection of more effective clinical treatment options.
Keywords: Large adrenal tumors, Adrenalectomy
* Correspondence: yangdeyong@dlmedu.edu.cn;
*Zongzong Zhang, Lina Wang, Jing Chen, and Xiunan Li contributed equally to this work and should be considered co-first authors.
1Department of Urology, The First Affiliated Hospital of Dalian Medical University, Dalian, China
Full list of author information is available at the end of the article
☒ BMC
@ The Author(s). 2019 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
Background
With the development of imaging technology, there is an increasing number of adrenal incidentalomas discov- ered incidentally. However, large adrenal tumors (LATs) are considered uncommon, with an incidence ranging from 8.6 to 38.6% [1, 2]. The possibility of malignancy increases with the increasing tumor volume [3-6]. For LATs, accurate preoperative assessments of the nature and origin of the tumors are important to the choice of therapy [7-9].
By definition, LATs range in size from more than 5 to 10 cm in diameter, with a consensus of approximately 5 cm [3, 10]. LATs cover a spectrum of various patholo- gies, ranging from benign lesions to adrenocortical car- cinoma or metastasis. Among 19 histopathological diagnoses, the most common was found to be adrenal cancer, followed by benign adenomas, pheochromocyto- mas, and metastasis [3]. The prognosis of different pathological types of LATs was found to differ. Patients with malignant tumors exhibited poor prognosis, espe- cially those with adrenal metastasis [11]. Accurate diag- nosis and functional evaluation of LATs and preoperative differentiation of benign and malignant tu- mors have great significance for the selection of appro- priate treatment approaches. Functional adrenal tumors and local invading lesions require more preoperative preparation [3] and may even affect the choice of surgi- cal approach [7]. Because the possibility of an uncom- plete curative resection with the laparoscopic adrenalectomy, open adrenalectomy is indicated in some cases [12]. The clinical, imaging, and pathological fea- tures of LATs play an important role in preoperative judgment of the nature of each tumor and selection of the best treatment.
In the present study, the clinical data of 251 patients with LATs in our hospital during a 10-year period from 2009 to 2018, including the pathological distribution, imaging manifestations, and surgical managements and prognosis, were collected and analyzed to provide a basis for the treatment of LATs.
Methods
From January 2009 to August 2018, among the patients admitted to the First Affiliated Hospital of Dalian Med- ical University, 1160 showed adrenal tumors in imaging reports. In this group, a total of 251 patients who had imaging manifestations showing that the size of adrenal tumors was larger than or equal to 5 cm were identified. Patient information (age, sex, survival time), laboratory work-up (blood cortisol, blood aldosterone, ACTH), tumor character (pathological diagnosis, imaging mani- festations, lesion location, diameter), and information re- lated to the operation (surgical methods, bleeding volume, blood transfusion volume, operation time,
drainage time, hospitalization time) were collected. All patients with a preoperative diagnosis of pheochromocy- toma received specific preparations to control hyperten- sion and facilitate rehydration. Most of these preparations included a receptor blockers and equilib- rium salt solution.
Among these patients, 178 underwent urological sur- gery. The typical surgical management plans were lap- aroscopic adrenalectomy and open adrenalectomy. Eighty-nine patients underwent open adrenalectomy. Laparoscopic adrenalectomy was performed in 89 pa- tients. Seventy-three patients did not undergo surgery, and clinical doctors made clinical diagnoses based on thorough history, clinical evaluation, hormonal and bio- chemical workup, and imaging reports.
The survival rates of 43 patients with adrenal metasta- sis and 29 patients with primary adrenal malignancies were determined according to the follow-up by phone. Two-month, 6-month, 12-month, 24-month, and 30- month survival rates were analyzed.
CT images of 117 patients with benign adenoma, pheochromocytoma, cortical carcinoma, metastatic car- cinoma, and gangliocytoma were collected. The CT characteristics including tumor diameter, shape, edge, heterogeneity, necrosis, calcification, pre-contrast at- tenuation, and contrast attenuation of the 117 patients were analyzed.
Statistical analysis
SPSS 21.0 software was used for statistical analysis. In case of skewed distribution and categorical data, rank sum test was used. A P value of < 0.05 was considered statistically significant for all tests.
Results
The pathological distribution of LATs and the character- istics of patients are shown in Table 1. Tumor size mea- sured on histopathological examination or imaging measurement ranges from 50 to 200 mm. The five most common LATs, including adrenal cyst (19.52%), pheo- chromocytoma (18.73%), metastases (17.13%), benign adenoma (16.73%), and adrenal cortical cancer (8.76%), were responsible for 80.88% of cases in this study. Be- nign LATs, including adrenal cyst (19.52%), pheochro- mocytoma (18.73%), benign adenoma (16.73%), myelolipoma (7.17%), gangliocytoma (3.19%), schwan- noma (0.8%), teratoma (1.20%), and hemangioma (0.80%), were responsible for 68.13%. Malignant LATs, mainly including metastases (17.13%), cortical carcinoma (8.76%), small cell carcinoma (1.20%), lymphoma (1.20%), and melanoma (0.4%), accounted for 28.69% of all cases.
Some obvious features in certain types of LATs were observed in the present study. The mean age of patients
| Diagnosis | Number, n = 251 | Age (years) (mean ± SD) | Male/female | Diameter (cm) (mean ± SD) | Location right/left |
|---|---|---|---|---|---|
| Adrenal cyst | 49 (19.52%) | 42.51 ± 14.28 | 21/28 | 8.19 ±2.97 | 18/31 |
| Pheochromocytoma | 47 (18.73%) | 50.21 ± 15.02 | 24/23 | 7.46 ±2.46 | 21/26 |
| Benign adenoma | 42 (16.73%) | 58.24 ± 13.64 | 20/22 | 6.38 ±1.67 | 21/21 |
| Myelolipoma | 18 (7.17%) | 56.22 ±11.39 | 6/12 | 8.58 ±2.03 | 16/2 |
| Gangliocytoma | 8 (3.19%) | 41.13 ± 13.74 | 6/2 | 7.85 ±2.73 | 5/3 |
| Schwannoma | 2 (0.80%) | 57.50 ±8.50 | 0/2 | 8.55 ± 3.05 | 1/1 |
| Teratoma | 3 (1.20%) | 49.00 ± 12.57 | 0/3 | 9.30 ±1.38 | 2/1 |
| Hemangioma | 2 (0.80%) | 42.50 ± 14.50 | 0/2 | 9.37 ±2.87 | 2/0 |
| Cortical carcinoma | 22 (8.76%) | 55.05 ± 15.89 | 9/13 | 8.97 ±3.33 | 13/9 |
| Small cell carcinoma | 3 (1.20%) | 41.33 ±8.65 | 2/1 | 9.90 ±5.77 | 1/2 |
| Lymphoma | 3 (1.20%) | 66.67 ±10.40 | 0/3 | 6.48 ±0.76 | 0/3 |
| Melanoma | 1 (0.40%) | 54 | 0/1 | 9.5 | 0/1 |
| Metastase | 43 (17.13%) | 63.91 ± 11.16 | 34/9 | 7.64 ±2.99 | 24/19 |
| Undefined | 8 (3.19%) | 57.25 ± 12.10 | 4/4 | 7.85 ±3.88 | 2/6 |
with lymphoma (66.67 years) and metastases (63.91 years) was higher than in other groups. In the case of metastases, the male/female ratio was 34/9, with a higher proportion of males than other groups. In patients with adrenal myelolipoma, most of the lesions were on the right side (R/L = 16:2).
Patients and tumor characteristics of bilateral LATs are shown in Table 2. Among the bilateral LATs, the most common diagnostic was malignant tumor (71.88%), followed by benign adenoma (15.63%), myeloli- poma (6.25%), gangliocytoma (3.13%), and pheochromo- cytoma (3.13%). The most common type of malignant tumor was metastatic (50%), followed by cortical
carcinoma (15.63%) and lymphoma (6.25%). Among ad- renal metastases, lung cancer was the main source, ac- counting for 50% of all adrenal metastases. It was followed by kidney cancer (12.5%), intestinal malignancy (12.5%), and prostate cancer (6.26%).
Generally, the prognosis of adrenal malignant tu- mors was poor (Table 3). Lung cancer was the most common primary carcinoma of adrenal metastasis, of which 41.67% of cases were solitary adrenal metasta- sis and 58.33% were systemic multiple metastases in- cluding adrenal metastasis. The 2-, 6-, 12-, 24-, and 30-month survival rates of patients with lung cancer were 96%, 58%, 33%, 8%, and 4%, respectively.
| Diagnosis | Number n=32 | Age (years) (mean ± SD) | Male/ female | diameter (cm) (mean ± SD) | |
|---|---|---|---|---|---|
| R | L | ||||
| Benign adenoma | 5 (15.63%) | 64.80 ±9.24 | 5/0 | 2.64 ±2.04 | 5.72 ±2.96 |
| Cortical carcinoma | 5 (15.63%) | 52.40 ± 12.18 | 3/2 | 8.95 ±3.12 | 5.49 ±4.51 |
| Myelolipoma | 2 (6.25%) | 53.50 ±6.50 | 1/1 | 7.85 ±0.55 | 1.40 ± 0.60 |
| Lymphoma | 2 (6.25%) | 74±1 | 0/2 | 4.02 ± 1.49 | 6.93 ±0.53 |
| Gangliocytoma | 1 (3.13%) | 54 | 1/0 | 7.50 | 4.00 |
| Pheochromocytoma | 1 (3.13%) | 66 | 0/1 | 6.50 | 0.60 |
| Metastatic carcinoma | (50.00%) | ||||
| Lung cancer | 8 (25.00%) | 62.63 ± 9.14 | 6/2 | 4.85 ±3.68 | 4.02 ±1.94 |
| Kidney cancer | 2 (6.25%) | 61.50 ±1.50 | 2/0 | 4.90 ±0.70 | 5.15 ± 3.35 |
| Intestinal malignancy | 2 (6.25%) | 64.50 ±0.50 | 2/0 | 2.25 ± 0.75 | 6.83 ±0.17 |
| Prostate cancer | 1 (3.13%) | 80 | 1/0 | 1.80 | 6.05 |
| Urothelial carcinoma | 1 (3.13%) | 84 | 1/0 | 10.73 | 4.00 |
| Liver cancer | 1 (3.13%) | 63 | 1/0 | 5.53 | 5.00 |
| Melanoma | 1 (3.13%) | 45 | 1/0 | 1.95 | 15.16 |
| Pathology types | Number | Survival rate (%) | ||||
|---|---|---|---|---|---|---|
| 2 m | 6 m | 12 m | 24 m | 30 m | ||
| Adrenal metastatic carcinoma | T (Mu/So) | |||||
| Lung cancer | 24 (14/10) | 96 (93/100) | 58 (43/80) | 33 (14/60) | 8 (0/20) | 4 (0/10) |
| Gastrointestinal cancer | 5 (4/1) | 60 (75/0) | 20 (25/0) | 0 (0/0) | 0 (0/0) | 0 (0/0) |
| Liver cancer | 5 (1/4) | 80 (0/100) | 80 (0/100) | 60 (0/75) | 40 (0/50) | 20 (0/25) |
| Renal carcinoma | 5 (2/3) | 80 (100/67) | 60 (50/67) | 20 (0/33) | 20 (0/33) | 20 (0/33) |
| Prostate cancer | 1 (1/0) | 0 | 0 | 0 | 0 | 0 |
| Pancreatic cancer | 1 (1/0) | 100 | 0 | 0 | 0 | 0 |
| Renal pelvis carcinoma | 1 (1/0) | 100 | 0 | 0 | 0 | 0 |
| Nose malignant melanoma | 1 (0/1) | 100 | 0 | 0 | 0 | 0 |
| Primary adrenal malignancy | T (N-Me/Me) | |||||
| Cortical carcinoma | 22 (13/9) | 91 (92/89) | 64 (69/56) | 45 (46/44) | 23 (31/11) | 14 (15/11) |
| Small cell carcinoma | 3 (2/1) | 100 (100/100) | 100 (100/100) | 100 (100/100) | 100 (100/100) | 67 (100/0) |
| Lymphoma | 3 (2/1) | 67 (100/0) | 33 (50/0) | 33 (50/0) | 33 (50/0) | 33 (50/0) |
| Melanoma | 1 (0/1) | 100 | 100 | 0 | 0 | 0 |
Adrenal cortical carcinoma accounted for 75.86% of the primary adrenal malignancy, 40.91% of which ap- peared distant metastatic at the time of initial diag- nosis. The 2-, 6-, 12-, 24-, and 30-month survival rates of patients with primary adrenal cortical car- cinoma were 91%, 64%, 45%, 23%, and 14%,
respectively. In this cohort, the mean survival time of primary adrenal malignant tumors was 19.17 months and that of metastatic adrenal tumors was 9.49 months. In general, the prognosis of patients with primary adrenal carcinoma without metastases was relatively good (Figs. 1, 2, 3, and 4).
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4 Primary adrenal malignancy with metastasis alive
Primary adrenal malignancy with no metastasis alive
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Metastatic carcinoma with Adrenal solitary metastasis alive
4 Primary adrenal malignancy with metastasis dead
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Fig. 1 The survival time of the adrenal malignancy
the survival time of adrenal metastasis of lung cancer and adrenalcortical carcinoma
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. multiple systemic metastases of lung cancer dead
adrenocortical carcinoma with no metastasis dead
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Fig. 2 The survival time of adrenal metastasis of lung cancer and adrenal cortical carcinoma
There was no significant difference between open adrenalectomy and laparoscopic adrenalectomy with respect to gender, age, or tumor location (Table 4). However, tumor diameter was larger in the open ad- renalectomy group than in the laparoscopic adrenalec- tomy group (P<0.05). There were more benign and
nonfunctional LATs in the laparoscopic adrenalec- tomy group than in the open adrenalectomy group (P < 0.05). Finally, there were significant differences in intraoperative bleeding (251.8 > 63.09 ml), blood trans- fusion (202.25> 8.99 ml), operation time (2.35> 1.96 h), hospitalization time (20.36>14.72 days), and
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Fig. 3 The survival graphs for adrenal metastases vs primary adrenal carcinoma
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Fig. 4 The survival graphs for adrenal metastases vs primary adrenal carcinoma without vs with metastases
| Open | Laparoscopy | P value | ||
|---|---|---|---|---|
| Age (years) | 52.21 ± 13.64 | 48.34 ± 15.98 | P=0.077 | |
| Size (cm) | 8.37 ± 2.71 | 6.74 ±2.10 | P =0.00 | |
| Gender | Male | 38 | 42 | P=0.548 |
| Female | 51 | 47 | ||
| Location | Right | 46 | 39 | P=0.231 |
| Left | 43 | 50 | ||
| Unilateral | 80 | 84 | P=0.267 | |
| Bilateral | 9 | 5 | ||
| Type | Benign | 74 | 83 | P=0.037 |
| Malignant | 15 | 6 | ||
| Non-function | 47 | 60 | P=0.047 | |
| function | 42 | 29 | ||
| Intraoperative | Bleeding | 251.80 ±503.28 | 63.09 ± 91.74 | P=0.00 |
| Transfusion (ml) | 202.25 ±378.64 | 8.99 ±59.28 | P=0.00 | |
| Injury | 2 | 0 | ||
| Operative time (h) | 2.35 ± 1.03 | 1.96 ±0.88 | P=0.012 | |
| Conversion | 6 | |||
| Postoperative | Fasting time (days) | 3.03 ± 1.13 | 2.39 ± 0.84 | P=0.00 |
| Drainage time (days) | 5.58 ±2.72 | 3.75 ± 3.06 | P=0.00 | |
| Hospital stay (days) | 20.36 ±8.07 | 14.72 ±5.66 | P=0.00 | |
| Postoperative complication (Clavien) | I | 46 | 62 | |
| II | 27 | 21 | ||
| III | 0 | 0 | ||
| IV | 15 | 6 | ||
| V | 1 | 0 |
postoperative drainage time (5.58 > 3.75 days) between the two groups.
CT features were compared among five types of LATs: be- nign adenomas, pheochromocytomas, cortical carcinomas, metastatic carcinomas, and gangliocytomas. As shown in Table 5, cortical carcinomas and gangliocytomas had a lar- ger diameter. In terms of tumor shape, a large proportion of benign adenomas and pheochromocytomas were round (94.12%), while metastasis was more common in lobulated tumors (47.06%). Among the infiltrative tumors, there was a high proportion of cortical carcinomas (50%). Benign aden- omas (97.06%), pheochromocytomas (94.29%), and ganglio- cytomas (85.71) were mostly circumscribed, while cortical carcinomas mostly presented ill-defined tumor margins (47.83%). Pheochromocytomas (94.29%), cortical carcinomas (88.89%), and metastatic carcinomas (95.65%) were mostly heterogeneous. However, the majority of gangliocytomas were homogeneous. Ninety-four percent of the pheochro- mocytomas were accompanied by necrosis, while most of the gangliocytomas had no necrosis. Tumors with calcifica- tion were more likely to be benign adenomas, whereas metastatic carcinomas and gangliocytomas had no calcifica- tion. CT features had readily visible specificity for the diag- nosis of benign and malignant tumors; for example, benign adenomas had a smaller pre-contrast (<10 Hu) which at- tenuation of other types of adrenal tumors did not have, whereas the contrast attenuation was more pronounced in pheochromocytoma than in other groups.
Discussion
Adrenal tumors are occasionally found in patients undergoing abdominal radiology, and the prevalence of
such findings increased with increasing age [13, 14]. Generally, the larger the tumor, the greater possibility of adrenal cancer [3-6]; therefore, it was even recom- mended that a tumor size greater than 5 cm should be considered an additional criterion for surgical treatment of adrenal incidental tumors [15]. For this reason, we de- cided to analyze tumors of this size to provide experi- ence and basis for preoperative differentiation and selection of appropriate treatment approaches of LATs.
LATs covered a wide range of pathological types. In other studies, benign LATs accounted for 62.59%, and malignant LATs accounted for 37.41% [3]. This is simi- lar to our present study. Thus, in clinical diagnosis of LATs, the possibility of benign tumors should be consid- ered first. However, a LAT still had a high probability of being a malignant tumor.
The presence of bilateral masses accounts for about 15% of the incidental adrenal tumors [16, 17]. In our study, ex- cept for malignant lesions, bilateral adrenal adenoma and lymphoma were the most common diagnoses. Metastatic or invasive neoplasms, congenital adrenal cortical hyper- plasia, bilateral adrenal cortical adenomas, and ACTH- independent macronodular adrenal hyperplasia were de- scribed by certain authors as the most likely diagnosis. Others did not find a difference in the frequency of malig- nant lesions between patients with bilateral adrenal tu- mors and unilateral ones [17]. In our group, however, the malignant rate of bilateral adrenal tumor was higher (71.88% vs 22.83%). This difference was caused by the high proportion of metastatic carcinomas. In this way, bilateral LATs should be suspected of malignancy, and further examination should be performed to exclude metastases.
| CT characteristics | Benign adenoma (n=34) | Pheochromocytoma (n=35) | Cortical carcinoma (n=18) | Metastatic carcinoma (n=23) | Gangliocytoma (n=7) | |
|---|---|---|---|---|---|---|
| Diameter (cm) | 6.55 ± 1.76 | 7.6.1 ± 2.27 | 9.37 ± 3.46 | 7.53 ± 2.44 | 8.18 ±2.76 | |
| Shape | Round | 32 (94.12%) | 30 (85.71%) | 7 (38.89%) | 13 (56.52%) | 6 (85.71%) |
| Lobulated | 2 (5.88%) | 2 (5.71%) | 5 (27.78%) | 8 (34.78%) | 0 | |
| Infiltrative | 0 | 3 (8.57%) | 6 (33.33%) | 2 (8.70%) | 1 (14.29%) | |
| Margin | Circumscribed | 33 (97.06%) | 33 (94.29%) | 7 (38.89%) | 15 (65.22%) | 6 (85.71%) |
| Ill-defined | 1 (2.94%) | 2 (5.71%) | 11 (61.11%) | 8 (34.78%) | 1 (14.29%) | |
| Heterogeneity | Homogeneous | 19 (55.88%) | 2 (5.71%) | 2 (11.11%) | 1 (4.35%) | 6 (85.71%) |
| Heterogeneous | 15 (44.12%) | 33 (94.29%) | 16 (88.89%) | 22 (95.65%) | 1 (14.29%) | |
| Necrosis | Negative | 20 (58.82%) | 2 (5.71%) | 6 (33.3%) | 10 (43.48%) | 6 (85.71%) |
| Positive | 14 (41.18%) | 33 (94.29%) | 12 (66.67%) | 13 (56.52%) | 1 (14.29%) | |
| Calcifications | 14 (41.18%) | 6 (14.14%) | 5 (27.78%) | 0 | 0 | |
| Pre-contrast attenuation (HU) | 23.94 ± 16.16 | 40.17 ±7.78 | 36.89 ± 10.59 | 32.35 ± 9.05 | 32.86 ±8.51 | |
| Contrast attenuation (HU) | Arterial phase | 50.94 ±23.01 | 87.46 ± 38.44 | 57.28 ± 17.67 | 55.26 ± 18.84 | 46.86 ±28.29 |
| Venous phase | 68.59 ±31.95 | 91.17 ±26.74 | 73.44 ± 29.22 | 58.13 ± 16.55 | 50.14 ±24.12 | |
| Delay phase | 55.32 ±26.32 | 79.37 ± 16.25 | 69.61 ± 24.75 | 53.48 ± 14.64 | 46.71 ± 17.81 |
Imaging diagnosis is of great value in estimating the na- ture of LATs. CT, MRI, and FDG-PET/CT can be used in clinical diagnosis of LATs. We compared the imaging fea- tures of the following five common LATs: (1) cortical car- cinoma: larger diameter, infiltrative, ill-defined tumor margin, heterogeneous; (2) metastatic carcinoma: lobu- lated tumors, heterogeneous, few calcifications; (3) benign adenomas: round, circumscribed, calcification; (4) ganglio- cytoma: larger diameter, circumscribed, homogeneous, no necrosis, few calcifications; and (5) pheochromocytoma: round, circumscribed, heterogeneous, necrosis, higher contrast attenuation.
Other authors described the presence of fat and a pre- contrast attenuation under 10 Hounsfield units have been found to be correlated with benignity [18, 19]. This is in accordance with our present study of LATs where benign adenomas had a pre-contrast attenuation (< 10 Hu) while other types of LATs did not have. Some scholars even thought that lesions with a pre-contrast at- tenuation of less than 10 Hu may be considered benign regardless of size [20]. However, in patients with adrenal metastases, 7% of cases with noncontrast HU ≤ 10 turned out to be malignant [21]. In our series, metasta- ses had no calcification, which was similar to other stud- ies except one [22]. This shows that CT cannot completely determine the nature of the tumor, and more comprehensive imaging examination was needed. In this case, contrast-enhanced washout CT was able to provide further information, showing that adenomas took up intravenous CT contrast rapidly and had a rapid loss of contrast, whereas malignant adrenal le- sions usually became enhanced rapidly but had a slower loss of contrast [23, 24].
Other imaging methods, such as MRI and PET/CT, can further differentiate the benign and malignant ad- renal tumors [25, 26]. PET/CT especially might be ef- fective in finding the extra-adrenal malignancies with low uptake [27, 28].
Laparoscopic adrenalectomy is widely used in the world, and it is the first choice for small adrenal benign tumors, on account of its advantages, including reduced postoperative pain, shorter hospitalization and recovery times, reduced complication rates, and better cosmetic results [29]. These advantages of laparoscopic surgery may be related to the small tumor volume and greater number of benign tumors in this group. More prospect- ive clinical studies are needed to compare the safety and efficacy of laparoscopic versus open surgery in the treat- ment of LATs. With the development of laparoscopic surgery and robotic surgery [30], tumor diameter has ceased to be a limiting factor in the surgical manage- ment of adrenal benign tumors. Laparoscopic adrenalec- tomy is preferred for benign LATs regardless of size or for LATs with radiological findings suspicious of
malignancies and a relatively small diameter (according to the experience of the surgeon) but no evidence of local invasion. For malignant LATs, especially those with local invasion, open surgery might be a more reasonable choice. Thus, the selection of surgical method should be evaluated comprehensively according to the experience of the surgeon and the characteristics of the tumor.
Systemic imaging examination before LAT surgery and screening malignant lesions in other parts and selecting suitable treatment for patients were of great significance. Among adrenal malignant tumors, 59.72% were metastatic and 40.28% were primary. Among me- tastases, 55.81% were accompanied by multiple systemic metastases. At the time of diagnosis of primary adrenal carcinomas, 41.38% of patients had distant metastasis. From our results, both cases of primary adrenal cancer and adrenal metastasis, once accompanied by metastases in other parts of the body, showed poor prognosis. In this case, surgical treatment was not the most appropri- ate method. In other studies, adrenocortical carcinoma patients had a very poor prognosis with a 5-year overall survival below 30% in most series [31]. Age, tumor prop- erty, general health, comorbidities, and patient prefer- ence should be taken into account in order to maximize the benefits to patients.
Our research had some specific limitations. The num- ber of cases in our single center was limited, and there were only a few tumors of rare pathology. There may be a large bias in the evaluation of clinical features and sur- vival prognosis of these patients; for some patients with adrenal metastases, the diagnosis mainly depended on clinical diagnosis, without any confirmation from patho- logical diagnosis. In some patients with bilateral tumors, pathology was only performed on one side of the body, which may also affect the statistical results of patho- logical distribution in this group of cases.
Conclusion
LATs were here affirmed to be a group of complex dis- eases with diverse sources. Understanding the clinico- pathological characteristics of LATs was found to be of great significance for accurately evaluating LATs and selecting the most suitable treatment.
Abbreviation
LATs: Large adrenal tumors
Acknowledgements
We thank LetPub (www.letpub.com) for its linguistic assistance during the preparation of this manuscript.
Authors’ contributions
Article topic design was contributed by DY and JW. Data processing was performed by ZZ, LW, JC, XL, DL, TC, XY, HH, XW, and XS. JW and DY are the corresponding authors. All authors read and approved the final manuscript.
Funding No funding.
Availability of data and materials
The data came from our hospital’s data system.
Ethics approval and consent to participate
The name of the ethics committee: Ethics Committee of First Affiliated Hospital of Dalian Medical University. Ethics References No: YJ-KY-FB-2018-59.
Consent for publication
We simply extracted data and did not involve the private information of patients.
Competing interests
The authors declare that they have no competing interests.
Author details
1Department of Urology, The First Affiliated Hospital of Dalian Medical University, Dalian, China. 2Department of Radiology, The First Affiliated Hospital of Dalian Medical University, Dalian, China.
Received: 24 July 2019 Accepted: 2 December 2019
Published online: 16 December 2019
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