Ann Thorac Surg 2009;88:2004-2006. doi:10.1016/j.athoracsur.2009.04.124
© 2009 The Society of Thoracic Surgeons
Case Reports
Atypical Presentation of an Atypical Carcinoid
Vanessa Van Brandt, MDa,*,
Stijn Heyman, MDa,
Eric Van Marck, MD, PhDb,
Jeroen Hendriks, MD, PhDa,
Paul Van Schil, MD, PhDa
a Department of Thoracic and Vascular Surgery, Antwerp University Hospital, Antwerp, Belgium
b Department of Pathology, Antwerp University Hospital, Antwerp, Belgium
Accepted for publication April 21, 2009.
* Address correspondence to Dr Van Brandt, Minderbroedersrui 41, Antwerp, 2000, Belgium (Email: vanessavanbr{at}gmail.com).
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Abstract
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Carcinoids are malignant neuroendocrine tumors consisting of a spectrum of neoplasms from low-grade typical carcinoid to high-grade small cell carcinoma. Primary neuroendocrine lesions in the mediastinum, especially the thymic region, are rare. Therefore, presently no uniform criteria are available for diagnosis, staging, risk assessment, and treatment. Generally, carcinoid tumors are indolent. However, when they occur in the thymic region, these tumors should be considered as aggressive neoplasms with an elevated risk of local recurrence and distant metastases.
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Introduction
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Presenting symptoms of thymic carcinoid tumors include chest pain, coughing, and weight loss. Associations with multiple endocrine neoplasia 1 syndrome and Cushing's syndrome have been described. Approximately half of the cases show no clinical manifestations. We describe a patient with a massive anterior mediastinal bleeding as first presentation of an atypical thymic carcinoid. This represents a very exceptional occurrence.
An 83-year-old man was admitted to the emergency room in December 2006 with mediastinal bleeding and left hemothorax. A computed tomographic scan showed a large anterior mediastinal hemorrhage (14 x 13.2 x 9.4 cm) accompanied by the left hemothorax and compression atelectasis of the left lung (Fig 1). His medical history only revealed a transurethral resection of the prostate. On admission, the patient was hemodynamically stable. As the chest computed tomographic scan showed massive bleeding, a median sternotomy was performed. Perioperative exploration displayed a hemorrhagic tumor at the thymic region with invasion of the left pleura, pericardium, and left phrenic nerve. A thymectomy was performed with partial resection of the pericardium and the left phrenic nerve to obtain a complete resection (Fig 2). The patient recovered well without respiratory problems, despite known paralysis of the left diaphragm.
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Fig 1. Multi-slice axial computed tomographic scan demonstrating a massive anterior mediastinal bleeding (14 x 13.2 x 9.4 cm) accompanied by compression atelectasis of left lung.
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Fig 2. Macroscopic appearance of thymic carcinoid (12 x 10 x 3 cm; weight, 163.3 g). Greyish tissue with smooth surface and diffuse foci of bleeding.
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Final pathologic diagnosis was atypical carcinoid of the thymus due to the presence of necrosis. However, mitotic activity was low (Fig 3). Approximately 15% of the tumor cells stained positively for the proliferation marker Ki-67. All removed lymph nodes were tumor free.
After discussion at multi-disciplinary oncological meeting, no adjuvant treatment was given. The patient was discharged from the hospital on January 15, 2007. Further follow-up was organized in a secondary hospital. A roentgenogram of the chest and a computed tomographic scan of the thorax were obtained 3 months after discharge. There were no signs of recurrence and the patient was in good clinical condition.
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Comment
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Thymic carcinoid tumors represent uncommon neoplasms. Their annual incidence has been reported to be approximately 0.01 of 100,000 [1], and less than 200 case reports have been described in the literature to date [2]. Consequently, no precise data are available to define evidence-based guidelines for diagnosis, treatment, and follow-up.
Generally, the neuroendocrine tumors are classified by a four-category scheme, including typical carcinoid (TC), atypical carcinoid, large cell neuroendocrine carcinoma, and small cell carcinoma [3, 4]. This approach has shown enough reproducibility toward accurate differentiation by pathohistologic criteria for the neuroendocrine lung tumors [3]. The criteria to discriminate typical carcinoid and atypical carcinoid have been revised by Travis and colleagues [5] who propose to outline atypical carcinoid by neuroendocrine morphology and mitotic counts between 2 and 10 per 2 mm2 of viable tumor or coagulative necrosis. Even though current classification correlates well with the clinical behavior of the neuroendocrine tumors of the lung, thymic carcinoids are likely to be more aggressive. Hence, they tend to have poor prognosis and are believed to have the same biological behavior as small cell carcinoma [6, 7]. A 5-year-survival rate of approximately 60% for local disease is described in the literature and recurrence is not uncommon [1, 2]. Moreover, due to their relatively benign clinical presentation, thymic carcinoids are generally discovered at a far advanced stage, which may also account for the poor prognosis [7]. In fact, our patient presented with a massive hemorrhage within an underlying thymic carcinoid. Therefore it is imperative to consider these tumors in the differential diagnosis of mediastinal masses when detected on imaging techniques.
A number of clinicopathologic studies have in vain attempted to determine a relevant classification system for thymic carcinoid, which could provide prognostic data [2, 8, 9]. Moran and Suster [8] suggest an inverse correlation between average survival rate and the differentiation of tumor. In contrast, Tiffet and colleagues [2] state that there is no prognostic relationship with macroscopic or microscopic features of the thymic carcinoid. Fukai and colleagues [9] confirmed that neither histologic grading nor TNM classification are good predictors for the prognosis of thymic carcinoid tumors, in contrast to thymoma and thymic carcinoma.
On the other hand, radical treatment may have an impact on survival rate. According to nearly every author, radical surgical excision of the thymus is the treatment of choice in case of a thymic carcinoid [1, 7, 10]. If the tumor is unresectable, debulking is still considered the best option.
The role of either adjuvant radiotherapy or chemotherapy remains controversial. Because local recurrence occurs relatively often, there might be a benefit of adjuvant radiotherapy. Indeed, this was proposed by Tiffet and colleagues [2] to prevent local recurrence. We decided not to administer adjuvant radiotherapy because a complete resection was obtained. In case of incomplete resection or local recurrence, adjuvant radiotherapy may be considered. Tiffet and colleagues [2] likewise suggest administration of adjuvant chemotherapy to control for distant metastases. Tumor regression has been reported in as many as 30% of patients with chemotherapy, although its role remains generally uncertain [11].
Our case of atypical carcinoid is presented by mediastinal hemorrhage, which we believe has not been previously described. A prospective study will never be performed because of its rare occurrence; hence, therapeutic guidelines should be based on case series and smaller, retrospective studies. Furthermore, additional studies are required to decide whether the current classification method for the neuroendocrine lung tumors can be applied for thymic tumors as well, in this way achieving a uniform approach to these rare tumors.
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References
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- Oberg K, Jelic S. Neuroendocrine bronchial and thymic tumors: ESMO clinical recommendation for diagnosis, treatment and follow-up Ann Oncol 2008;19(Suppl 2):102-103.
- Tiffet O, Nicholson A, Ladas G, Sheppard M, Goldstraw P. A clinicopathologic study of 12 neuroendocrine tumors arising in the thymus Chest 2003;124:140-147.
- Travis W, Gal A, Colby T, Kumstra D, Falk R, Koss M. Reproducibility of neuroendocrine lung tumor classification Human Pathol 1998;29:272-279.[Medline]
- Fujiwara K, Segawa Y, Takigawa N, et al. Two cases of atypical carcinoid of the thymus Int Med 2000;39:834-838.
- Travis W, Rush W, Flieder D, et al. Survival analysis of 200 pulmonary neuroendocrine tumors with clarification of criteria for atypical carcinoid and its separation from typical carcinoid Am J Surgl Pathol 1998;22:934-944.
- Gal A, Kornstein M, Cohen C, Duarte I, Miller J, Mansour K. Neuroendocrine tumors of the thymus: a clinicopathological and prognostic study Ann Thorac Surg 2001;72:1179-1182.[Abstract/Free Full Text]
- Cheau-Feng Lin F, Chih-Ming Lin, Chih-Cheng H, Wing-Yin L, Liang-Shun W. Atypical thymic carcinoid and malignant somatostatinoma in type 1 multiple endocrine neoplasia syndrome Am J Clin Oncol 2003;26:270-272.[Medline]
- Moran C, Suster S. Primary neuroendocrine carcinoma (thymic carcinoid) of the thymus with prominent oncocytic features: a clinicopathologic study of 22 cases Mod Pathol 2000;13:489-494.[Medline]
- Fukai I, Masoaka A, Fujii Y, et al. Thymic neuroendocrine tumor (thymic carcinoid): a clinicopathologic study in 15 patients Ann Thorac Surg 1999;67:208-211.[Abstract/Free Full Text]
- John L, Hornick P, Lang S, Wallis J, Edmondson S. Giant thymic carcinoid Posgrad Med J 1991;67:462-465.
- Caplin M, Buscombe J, Hilson A, Jones A, Watkinson A, Burroughs A. Carcinoid tumor The Lancet 1998;352:799-804.
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Abstract
Introduction
