CASE REPORTS
Cushing’s Syndrome in an Infant Secondary to Malignant Adrenocortical Tumors with Somatic Mutation of Beta-Catenin
THEERAWUT PUSANTISAMPAN, 1,2 SURASAK SANGKHATHAT,2,3* KANITA KAYASUT,2,4 SAMORNMAS KANNGURN, 2,4 SOMCHIT JARURATANASIRIKUL,5 TEERACHIT CHOTSAMPANCHAROEN,5 AND SUPIKA KRITSANEEPAIBOON
1Center for Bioinformatics, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand 90110
2Tumor Biology Research Unit, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, Thailand 90110
3Department of Surgery, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, Thailand 90110
4Anatomical Pathology Unit, Department of Pathology, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, Thailand 90110
5Department of Pediatrics, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, Thailand 90110 6Department of Radiology, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, Thailand 90110
Received July 26, 2009; accepted September 30, 2009; published online October 19, 2009.
ABSTRACT
A role of beta-catenin (CTNNB1) in the molecular pathogenesis of adrenocortical carcinoma (ACC) has been suspected in adult ACC and pediatric pigmented nodular adrenocortical disease, but it has never been reported in pediatric ACC. We present the case of a 4-month-old Thai infant who had Cushing’s syndrome secondary to bilateral adrenal tumors with hepatic metastasis. The child was successfully treated with a bilateral adrenalectomy and wedge resection of the liver nodule. Histopathology revealed bilateral adrenocortical tumors with different histologic grades; the right tumor had a higher score, according to modified Weiss criteria. On molecular study, a deletion mutation of beta-catenin involving codons 44 to 45 was detected in the right adrenal tumor. The same mutation was found in peripheral blood before treatment; this mutation disappeared after tumor removal. The left tumor harbored wild-type beta-catenin. Immunohistochemistry showed nu- clear accumulation of beta-catenin on the right adrenal tumor and the metastatic nodule. In summary, we present evidence that supports the role of the Wnt-signaling pathway in the carcinogenesis of pediatric adrenocortical carcinoma.
Key words: adrenocortical carcinoma, beta-catenin, Wnt- signaling
INTRODUCTION
Adrenocortical carcinoma (ACC) is a rare malignancy, with an approximate incidence of 1 to 2 cases per million-years in
adults [1]; rates are much lower in children [2]. Although ACC in infants shares the same clinicopathological features as it does in adults, pediatric ACC generally has a better prognosis and a distinct molecular pathogenesis. In pediatric ACC, germline mutations in TP53 have been reported to measure 50% to 80% [2,3]. On the other hand, the majority of TP53 alterations in adult ACC are somatic mutations [4]. Recent studies have discovered somatic mutations of beta- catenin (CTNNB1) in adult ACC. Beta-catenin is known to be the central molecule of the canonical Wnt-signaling pathway, which plays a crucial role in the tumorigenesis of various pediatric embryonal tumors [5]. Mutations of beta- catenin were detected in 4 of 13 cases of adult ACCs in one report [6] and in 0 of 4 cases in another [7]. Although sequence alterations of this same gene have been demon- strated in pediatric pigmented nodular adrenocortical disease [8], they have never been reported in pediatric ACC cases.
On molecular genetic study of 4 pediatric ACC cases from our institution, we detected an activating mutation of beta-catenin in one infant case of bilateral ACC who presented with Cushing’s syndrome. The nature of the bilaterality together with a metastatic focus gave us some interesting data regarding tumor clonality and the role of beta-catenin in tumor progression.
CASE REPORT
A 4-month-old female infant was presented to us with a history of obesity and hypertension for 2 months. The girl had been delivered prematurely at 35 weeks by cesarean section as a result of placenta previa. The infant’s birth
*Corresponding author, e-mail: surasak.sa@psu.ac.th
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weight was 3500 g (50th percentile of Thai normal growth curve), and her length was 47.5 cm (10th percentile). Her weight increased to 5.5 kg (P97) at 2 months and to 8.9 kg (155% of P50) at 4 months, while her length was 58.0 cm (P75) at 2 months and 62 cm (P75) at 4 months. The patient was the 1st child of a 34- year-old mother and a 30-year-old father who were both healthy. Except for an incidence of transient neonatal hypoglycemia, her perinatal history was uneventful.
On our initial examination at 4 months, the child had cushingoid facies and an obese appearance. Her blood pressure was 123/82 mm Hg, which lowered somewhat to 107/76 mm Hg at rest. Other features and tests were not remarkable. Baseline serum cortisol was 46.19 ug/dL. A high-dose dexamethasone suppression test showed an “insuppressible” result. A computerized tomography of her abdomen revealed a large heterogeneous enhancing mass measuring 39 × 51 × 65 mm in size at the right adrenal fossa (Fig. 1). There was diffuse enlargement of the left adrenal gland without a focal lesion. Bilateral medullary nephrocalcinosis was also noted.
On operation, an encapsulated right adrenal mass compressing the inferior vena cava was found. After a right adrenalectomy, the bisection surface of the resected mass showed multiple tiny calcification spots. The left adrenal gland looked globally enlarged, measuring 5 × 6 × 5 cm. A left adrenalectomy was done. There was also a hepatic nodule measuring 2 cm in diameter at the antero- medial segment of the left lobe. En bloc hepatic resection was performed. The patient was maintained with an oral steroid supplement and remained disease-free through up to 26 months of regular follow-up. Her body weights at 12 months and 20 months postoperation were 9.9 kg (P30) and 12.6 kg (P50), respectively.
Histopathology of the right adrenal tumor showed small round tumor cells arranged in a cordlike structure with macrotrabeculae. The clear cell component was less than 25%. The tumor also showed some mitotic figures and pleomorphisms. There was an area of capsular invasion and foci of tumor necrosis (Fig. 2). Taken together, the histopathology of the right adrenocortical tumor was consistent with a score of 3 according to the modified Weiss criteria [9]. The left adrenal gland revealed an adrenocortical tumor with high nuclear polymorphisms. The clear cell component on this side was higher than on the other but was still less than 25% and was given a score of 2 points. The liver nodule represented a metastatic ACC that had a histopathologic pattern closely resembling the right adrenal tumor.
On molecular study of frozen tumor tissue, hetero- zygous deletion of the beta-catenin gene sequence involving 6 bases of codons 44 and 45 was detected in the adrenocortical tumor tissue from the right adrenal gland. The mutation was faintly detectable in the liver metastasis but was not detected in the left adrenal tumor. Interestingly, the same mutated sequence was detected in the pretreatment blood of the patient, but this sequence was no longer detectable at 3 months postadrenalectomy. Both parents were negative. Screening for TP53 muta- tions covering exons 4 to 8 and 10 gave negative results. A blood DNA sample of the patient was also submitted for a whole coding sequence study of PRKAR1A (Gendia, Belgium), which reported a negative result.
Immunohistochemistry demonstrated positive nucle- ar accumulation and cytoplasmic staining of beta-catenin protein in the ACC tumor at the right adrenal gland in approximately 90% of the tumor cells. The metastatic nodule of the liver showed focally positive nuclear staining in 60% of the tumor cells. The left adrenal tumor showed weak immunoreactivity confined to the cell membranes (Fig. 3).
DISCUSSION
An adrenocortical tumor is an uncommon pediatric tumor, and a case of bilateral disease is even rarer and more interesting in terms of its molecular pathogenesis. Bilater- ality has been reported to measure 2% to 6% in adult adrenocortical carcinoma [10], and this value is estimated to be less in pediatric cases [11]. The true figure is difficult to assess, as most studies have had only a limited number of patients, and most reports have not focused on the laterality aspect. In a large series of 30 pediatric adrenocortical tumors, only 2 bilateral ACCs were reported [12].
The hypothesis of ACC pathogenesis, as proposed by Libé and Bertherat [13], fits the multistep carcinogenesis theory. A malignant clone is believed to arise after certain signals have successfully transformed a potential cell in the benign tumor tissue. In our case, nuclear accumulation of beta-catenin protein in the right-sided tumor, which had a larger size and more aggressive histology, indicated that activation of the Wnt-signaling was associated with the
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malignant behavior of this adrenal tumor. Mutation of beta- catenin involving its main phosphorylation site at codon 45 theoretically explains the signal activation through defec- tive degradation of the protein [5]. The aberrant sequence found at the right-sided tumor was consistent with its nuclear immunoreactivity. The same alteration found in peripheral blood before the tumor removal (which disap- peared postoperatively) indicates that at least some of the circulating tumor cells harbored the beta-catenin mutation. Although evidence of mutation was not clearly apparent in the liver metastasis, the nuclear staining indicated that the metastatic tissue and the right adrenal tumor shared the same feature of Wnt-signaling activation.
Our observations are in line with those of a previous study [14] focusing on beta-catenin in adult adrenocor- tical tumors, which identified nuclear accumulation of beta-catenin in both benign and malignant adrenal tumors. In the pediatric age group, beta-catenin mutations have been reported in primary pigmented nodular adrenocor- tical disease, especially those mutations associated with the Carney complex [8]. The gross and microscopic
pathology in our reported case was consistent with an isolated adrenocortical tumor, but not with pediatric pigmented nodular adrenocortical disease.
We speculate that there was an unspecified genetic event that caused a primary adenomatous change to the adrenal gland, leading this tumor, and that this alteration was a germline mutation resulting in bilateral tumors. At the time of the patient’s presentation we suspected a germline mutation of PRKAR1A or TP53 as the predis- posing event, but the study could not detect any lesions on these genes. As there were multiple tumor foci in our case, evidence that the larger size and higher histologic grade tumor shared features of Wnt-signaling activation with the circulating tumor cells and the metastatic nodule, we believe this offers quite solid ground for speculating that Wnt-signaling activation was involved in the metastatic process of the adrenocortical tumor.
In summary, on genetic screening of beta-catenin and TP53 in 4 pediatric adrenocortical carcinomas, we detected one case of bilateral adrenocortical tumor with unilateral somatic mutation of beta-catenin. The same
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mutation was detected in the circulating tumor cells, and this mutation disappeared after treatment. The case offers further evidence for a role of the Wnt-signaling pathway in the pathogenesis of this cancer.
ACKNOWLEDGMENTS
All genetic studies, except the PRKAR1A study, were conducted in the Molecular Biology Laboratory, Faculty of Medicine, at Prince of Songkla University. PRKAR1A genotyping was performed by Gendia, Belgium (labora- tory code: 2009.0379). Dave Patterson of the International Affairs Office of the Faculty of Medicine edited the manuscript for English.
REFERENCES
1. Lindholm J, Juul S, Jørgensen JO, et al. Incidence and late prognosis of Cushing’s syndrome: a population-based study. J Clin Endocrinol Metab 2001;86:117-123.
2. Wagner J, Portwine C, Rabin K, et al. High frequency of germline p53 mutations in childhood adrenocortical cancer. J Natl Cancer Inst 1994;86:1707-1710.
3. Varley JM, McGown G, Thorncroft M, et al. Are there low- penetrance TP53 alleles? Evidence from childhood adrenocortical tumors. Am J Hum Genet 1999;65:995-1006.
4. Latronico AC, Pinto EM, Domenice S, et al. An inherited mutation outside the highly conserved DNA-binding domain of the p53 tumor suppressor protein in children and adults with sporadic adrenocor- tical tumors. J Clin Endocrinol Metab 2001;86:4970-4973.
5. Koesters R, von Knebel Doeberitz M. The Wnt signaling pathway in solid childhood tumors. Cancer Lett 2003;198:123-138.
6. Tissier F, Cavard C, Groussin L, et al. Mutations of beta-catenin in adrenocortical tumors: activation of the Wnt signaling pathway is a frequent event in both benign and malignant adrenocortical tumors. Cancer Res 2005;65:7622-7627.
7. Tadjine M, Lampron A, Ouadi L, et al. Frequent mutations of beta- catenin gene in sporadic secreting adrenocortical adenomas. Clin Endocrinol (Oxf) 2008;68:264-270.
8. Tadjine M, Lampron A, Ouadi L, et al. Detection of somatic beta- catenin mutations in primary pigmented nodularadrenocortical disease (PPNAD). Clin Endocrinol (Oxf) 2008;69:367-373.
9. Aubert S, Wacrenier A, Leroy X, et al. Weiss system revisited: a clinicopathologic and immunohistochemical study of 49 adrenocor- tical tumors. Am J Surg Pathol 2002;26:1612-1619.
10. Linda NG, Libertino JM. Adrenocortical carcinoma: diagnosis, evaluation and treatment. J Urol 2003;169:5-11.
11. Ribelro RC, Michalkiewicz EL, Figuelredo BC, et al. Adrenocor- tical tumors in children. Braz J Med Biol Res 2000;33:1225-1234.
12. Cifti AO, Senocak ME, Tanyel C, et al. Adrenocortical tumors in children. J Pediatr Surg 2001;36:549-554.
13. Libé R, Bertherat J. Molecular genetics of adrenocortical tumors, from familial to sporadic diseases. Eur J Endocrinol 2005;153:477- 487.
14. Gaujoux S, Tissier F, Groussin L, et al. Wnt/beta-catenin and 3’,5’- cyclic adenosine 5’-monophosphate/protein kinase A signaling pathways alterations and somatic beta-catenin gene mutations in the progression of adrenocortical tumors. J Clin Endocrinol Metab 2008;93:4135-4140.
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