Neuroendocrine carcinoma (carcinoid) of the thymus associated with Cushing's syndrome

Neuroendocrine neoplasms of the thymus

Neuroendocrine neoplasms of the thymus (tNENs), including typical carcinoid, atypical carcinoid, large cell neuroendocrine carcinoma, and small cell carcinoma, are rare tumors with scarce clinical and pathological data available in the literature. They share many common features with neuroendocrine neoplasms in other organs, such as those in the lungs, while demonstrating some distinct clinical and pathological features. This review aims to give an updated overview of each category of tNENs, focusing primarily on the pathologic diagnosis and differential diagnosis of these tumors.

The Utility of Fine Needle Aspiration (FNA) Biopsy in the Diagnosis of Mediastinal Lesions

Fine needle aspiration is a minimally invasive, low-morbidity, and cost-efficient technique for the sampling of mediastinal lesions. Additionally, ancillary testing on FNA samples can be used for the refinement of diagnoses and for treatment-related purposes (flow cytometry, cytogenetics, immunohistochemistry, and molecular diagnostics). Mediastinal lesions, however, can show a variety of lineages and morphologic features, giving rise to diagnostic dilemmas. As a result, the differential diagnosis can vary widely and becomes especially challenging due to the smaller sample size on FNA and the variability in component sampling. For appropriate patient management and to determine the correct treatment strategies, accurate pathologic diagnoses are paramount. In this review, we present the cytomorphologic features together with the immunophenotypic findings of mediastinal lesions, with emphasis on the diagnostic challenges and pitfalls in FNA cytology samples, including smears and cell block sections.

Atypical Carcinoid Syndrome in a Patient Presenting With Pericarditis and Supraventricular Tachycardia: A Case Report

Atypical carcinoids are more uncommon than typical carcinoids, and carcinoid syndrome in general is quite rare. Mediastinal atypical carcinoid is a rare neuroendocrine tumor (NET) that spreads aggressively and rapidly. Morphologically, neuroendocrine tumors are classified into typical carcinoid, atypical carcinoid, small cell carcinoma, and large cell neuroendocrine carcinoma, and the latter two are high-grade tumors. The incidence of atypical carcinoid is rare, and the prognosis is poor, which makes larger trials difficult. It may affect the liver, lungs, or mediastinum with or without metastasis. We present a case of a 47-year-old male patient who presented with chest pain and was found to be in supraventricular tachycardia (SVT) on initial presentation to the hospital. A repeat electrocardiogram (ECG) showed widespread ST-segment elevation. A bedside echocardiogram showed a moderate pericardial effusion, and the patient underwent a coronary angiogram, which showed normal coronary arteries. A computed tomography pulmonary angiogram (CTPA) showed a right mediastinal mass, and the patient was referred to oncology following a discussion in a multidisciplinary team (MDT) meeting. He was commenced on neoadjuvant chemotherapy and has been followed up since in the outpatient clinic. This case is unique due to the initial presentation of supraventricular tachycardia and pericardial effusion.

Ectopic Cushing's syndrome due to thymic neuroendocrine tumours: a systematic review

Knowledge of ectopic Cushing's syndrome (CS) due to thymic neuroendocrine tumours (NETs) comes from short series or single cases. Our aim is to perform a systematic review using PubMed, Embase, Scopus, Ovid Medline and Biosis Previews of all cases with ectopic CS due to thymic NETs reported in the last 40 years and describe one illustrative patient attended in our institution. Search of literature: From 162 patients, 58.6% were male and mean age was 34.6 ± 13.9 years-old. Median of symptoms until diagnosis was 6 [2-24] months and 62% had aggressive CS. Imaging was positive in 93.7% (chest X-ray), 97.8% (computed tomography), 80.7% (somatostatin receptor scintigraphy) and median tumour size was 47 [25-68.5] mm. At presentation, 18% had localized disease, 26.2% locally invasive and 55.7% advanced. Eighty-eight present underwent surgery and histological subtypes were atypical (46.7%), typical (30.4%) and carcinoma (21.7%). Tumour persisted or recurred in 70.1%, 63% received radiotherapy and 45.2% chemotherapy. Follow-up median was 26.6 [14.5-57.5] months and mortality was reported in 35.8% with median survival of 38 [19-60] months. MEN-1 mutation was referred in 3.1%. Comparatively, carcinomas had aggressive CS more frequently while atypical showed advanced disease more often. In conclusion, thymic NETs causing ectopic CS are presented as aggressive hypercortisolism in the middle aged population. The disease is commonly extended at diagnosis and persists or recurs after surgery in most patients with a short term high mortality.

Cyclic ACTH-secreting thymic carcinoid: a case report and review of the literature

Cyclic Cushing's syndrome (CS) due to thymic carcinoid is a rare disorder. We report a case of cyclic CS due to ectopic adrenocorticotropic hormone (ACTH)-secreting atypical thymic carcinoid tumor and reviewed similar cases published in the literature. Our patient had hypercortisolemia lasting approximately one month, followed by normal cortisol secretion, with relapse one year later. Histopathology revealed an atypical ACTH-positive thymic carcinoid. Ectopic CS can be derived from atypical thymic carcinoids, which can be aggressive tumors with early relapse, suggesting that this type of tumor probably needs aggressive treatment.

Recent advances and conceptual changes in the classification of neuroendocrine tumors of the thymus

Neuroendocrine tumors of the thymus (TNET) are exceedingly rare neoplasms. Their histomorphology is identical to neuroendocrine tumors elsewhere in the body (in particular the lungs) and bears no similarity with thymomas and thymic carcinomas. Recent molecular findings have profoundly changed our perception of these tumors and may impact future histological classification systems.

[Surgical treatment of ACTH-ectopic syndrome]

ACTH-ectopic syndrome is a severe, multiple-symptom disease characterized by secretion of adrenocorticotropic hormone (ACTH) by ectopic tumor, increased release of adrenal cortical hormones and clinical picture of hypercorticism. Diagnosis and treatment of ACTH-ectopic syndrome is still difficult problem despite the achievements of modern medicine. There are several unresolved issues including optimal diagnostic algorithm, indications for various surgical procedures and their optimal dates. This review is devoted to these questions.

ACTH-producing thymic neuroendocrine tumor initially presenting as psychosis: A case report and literature review

A 32-year-old woman was referred to our hospital because of severe psychosis and was found to have an ectopic ACTH-producing thymic neuroendocrine tumor. Laboratory data revealed an elevated serum cortisol and plasma ACTH level, hypokalemia, and metabolic alkalosis. Chest computed tomography (CT) revealed an anterior mediastinal mass and multiple pulmonary nodules. As the patient was unable to communicate because of her consciousness disturbance, she was managed with artificial ventilation and deep sedation. Metyrapone and potassium supplementation were administered, and steroid psychosis gradually improved. Thoracic surgery was performed and the histopathological diagnosis was thymic neuroendocrine tumor with positive anti-ACTH immunohistochemical staining. Here we present details of the case and review the literature.

Two types of ectopic Cushing syndrome or a continuum? Review

BACKGROUND

Two types of ectopic Cushing syndrome (ECS) are described: ECS associated with aggressive neoplasms, and ECS with indolent and occult tumors, however, there is a lack of studies that thoroughly review their characteristics.

METHODS

A systematic review was carried out on PUBMED of all the papers about the ECS, in order to better define the types of this subcategory of Cushing's syndrome, highlighting the differential aspects between these subgroups.

RESULTS

It was found that in 50% of cases the prototypic "aggressive" ECS is caused by small cell lung carcinomas (SCLC). In these cases, the clinical presentation may be atypical, predominating the signs and symptoms derived from the protein catabolism. Cortisol and ACTH levels are extremely high, the clinical presentation is abrupt (< 3-6 months) and the tumor is usually advanced, being impossible a curative treatment. On the other hand, "indolent" ECS is mainly represented by carcinoid tumors (CT). In these cases the clinical presentation overlaps enormously with that of Cushing's disease (CD). Cortisol and ACTH levels are slightly elevated, the clinical presentation is progressive (> 6 months) and the prognosis is usually good, and a curative treatment is possible in about 75% of the cases.

CONCLUSION

Although there is no absolute differentiation between the two extremes of ECS, a classification could be established in two groups, guided by its clinical and biochemical characteristics, and mainly by the type and stage of the ACTH-secreting tumor. However, a small percentage of tumors do not fit in this simple grouping, and may present both phenotypes or an intermediate one.

Ectopic Cushing syndrome: Report of 9 cases

INTRODUCTION

Ectopic Cushing's syndrome (ECS) is a rare condition caused by ACTH secretion by extrapituitary tumors. Its low frequency makes it difficult to acquire experience in its management. The aim of this study was to describe patients with ECS seen at the endocrinology department of a tertiary hospital over 15 years.

METHODS

This was a retrospective study of the clinical, biochemical and radiographic data, treatment, and course of patients with ECS seen from 2000 to 2015.

RESULTS

Nine patients (6 of them female) with a mean age of 47 years were included in the study. The clinical syndrome developed in less than 3 months in all cases but one, and most patients also had edema, hyperpigmentation and/or hypokalemia. Mean urinary free cortisol and ACTH levels were 2,840μg/24h and 204pg/mL respectively. The ectopic origin was confirmed by a combination of dynamic non-invasive tests and radiographic studies in most cases. The tumor responsible could be identified in 8 cases, and 7 patients had metastatic dissemination. Primary treatment was surgery in one patient, surgery combined with systemic therapy in 3, and chemotherapy in the other 3 patients. Bilateral adrenalectomy was required in 4 patients to control hypercortisolism. After a mean follow-up of 40 months, 3 patients died, 5 were still alive, and one had been lost to follow-up.

CONCLUSIONS

Our study confirms that ECS covers a wide spectrum of tumors of different aggressiveness and nature. The ectopic origin of Cushing's syndrome can usually, be suspected and confirmed in most cases without the need for invasive tests. Control of both hypercortisolism and the tumor requires multiple treatment modalities, and multidisciplinary management is recommended.

A Case Report of Metastatic Atypical Thymic Carcinoid with Ectopic ACTH Production: Locoregional Control after Adaptive Radiation Treatment

Thymic carcinoid is an extremely rare malignancy. This tumor is often associated with endocrine disorders such as Cushing's syndrome, multiple endocrine neoplasia type 1 and superior vena cava syndrome. We describe the case of a 44-year-old Italian woman with metastatic atypical thymic carcinoid secreting ectopic adrenocorticotropic hormone who was treated with adaptive radiation therapy with a curative dose schedule for a symptomatic mediastinal tumor. After 22 months, the patient was in good clinical condition, presenting stable disease without any evidence of local or systemic progression. To our knowledge there are no previously reported data regarding radical radiotherapy in the treatment of thymic carcinoids.

Spinal Metastasis Resulting from Atypical Thymic Carcinoid: A Case Report

BACKGROUND

Thymic carcinoid with spinal metastasis is an extremely rare entity. Clinically, the tumor presents either by its endocrine manifestations or by mechanical compression of surrounding structures. However, no previously published case studies have reported neck pain and neurologic deficit in the initial presentation of an atypical thymic carcinoid.

CASE DESCRIPTION

A 56-year-old man, a nonsmoker, presented with a 12-month history of intermittent neck pain and a 1-month history of progressive numbness and weakness of the right upper limb. Cervical MRI showed multiple abnormal signals and C2 soft-tissue mass intruding into the vertebral canal. Cervical CT scan showed multiple bone lesions. The diagnosis of thymic carcinoid was obtained by preoperative lymph node biopsy. The patient underwent cervical laminectomy and occipitocervical fixation. Significant alleviation of pain and neurologic improvement were achieved. The postoperative pathological examination confirmed the diagnosis of thymic carcinoid.

CONCLUSIONS

Neck pain and neurologic deficit could be the first presentation of thymic carcinoid with spinal metastasis. Palliative surgery is an effective method to improve quality of life in patients with thymic carcinoid with spinal metastasis.

Neuroendocrine tumors of the thymus and mediastinum

Neuroendocrine tumors of the thymus (tNET) and mediastinum are very rare neoplasms with scarce available data. All subtypes [typical and atypical carcinoid tumors (TC and AC), large cell neuroendocrine and small cell carcinoma (SCC)] observed elsewhere in the body occur also in the mediastinum and show only few if any organ-specific morphological differences. Although all available data suggest that the broad principles that govern the biology (and hence) the classification of these tumors in general apply also to tNET, there are a few noteworthy peculiarities related e.g., to risk factors, relative frequency and also to molecular genetic features. In this review, we will briefly summarize current knowledge on tNET with a special emphasis on shared and private features in comparison e.g., with pulmonary NET, which have traditionally been regarded the next closely related NET group.

Bronchial and Thymic Carcinoid Tumors

Bronchial and thymic carcinoids are rare. We present epidemiologic data and potential risk factors. The approach to bronchial and thymic carcinoid patients is discussed, from the initial diagnosis and evaluations to treatment. These malignancies follow staging systems of their site of origin. Because bronchial and thymic carcinoids are rare, we use many treatment strategies that have been demonstrated in gastrointestinal and pancreatic neuroendocrine tumors. The lack of information regarding efficacy in bronchial and thymic carcinoids, as well as the scarcity of therapeutic options available, demands the importance of clinical trials that include these patients.

Carcinoid Tumors of the Thymus

Twenty-five cases of neuroendocrine carcinoma of the thymus associated with Cushing's syndrome have been reported since 1972. 1 We report two new cases of thymic carcinoid, one of which presented with Cushing's disease. These patients were successfully treated and were asymptomatic at the time of first follow-up.

Pancreatic metastasis resulting from thymic neuroendocrine carcinoma: A case report

Thymic neuroendocrine carcinoma (NEC) is a rare type of cancer. Unlike other thymic epithelial tumors and carcinoids originating in other locations, thymic NEC possesses a more aggressive biological behavior, including invasion to proximal structures, local recurrence and distant hematogenous metastasis. Distant metastasis is often observed in the bones, lungs, spleen, liver and adrenal glands. However, pancreatic metastasis resulting from thymic NEC is extremely uncommon, and only a few cases of patients with this disease have been reported. The current study presents the case of a patient with pancreatic metastasis resulting from thymic NEC. The patient was admitted to hospital with an anterior mediastinal neoplasm, which was identified using chest enhanced computed tomography. The patient underwent a monobloc excision of the tumor with resection of involved structures. Subsequently, a pathological diagnosis of atypical thymic carcinoid was provided, according to the morphological characteristics observed and the expression of neuroendocrine markers, as identified by immunohistochemistry. Following surgery, the patient received adjuvant chemotherapy and radiotherapy. However, ~2 years after surgery, metastasis at the pancreatic head was identified. The patient underwent a total pancreatectomy and splenectomy, and did not receive any post-operative therapies; however, the patient succumbed to the disease 9 months following surgery. Overall, the results from the present study demonstrate the clinical features of thymic NEC, which may aid with the diagnosis of this rare disease in other patients.

Successful Pregnancies after the Treatment of a Thymic Carcinoid

The present report describes the case of a woman diagnosed with an adrenocorticotropic hormone- (ACTH-) secreting thymic carcinoid associated with Cushing's syndrome. Treatment consisted of tumour resection and 131-I-meta-iodobenzylguanidine (MIBG) therapy. In spite of her iatrogenic menopausal state she twice became pregnant and delivered two healthy babies but developed recurrences during both pregnancies. The last recurrence presented as a primary breast cancer. Despite poor prognosis our patient survived for eleven years. To our knowledge this is the first report of successful pregnancy and delivery in a patient with a thymic carcinoid.

Ectopic ACTH syndrome caused by desmopressin-responsive thymic neuroendocrine tumor

A 32-year-old Chinese woman with rapid weight gain and progressive edema was found to have typical Cushingoid features. Her endocrine data were consistent with a diagnosis of ACTH-dependent Cushing's syndrome. To differentiate ectopic ACTH syndrome (EAS) from Cushing's disease (CD), various dynamic endocrine and imaging tests were performed. Her ACTH response was negative to corticotropin-releasing hormone (CRH) and positive to desmopressin. Magnetic resonance imaging of the pituitary showed no mass lesion. Computed tomography scan of the chest revealed a large mass (21 × 15 mm) in the anterior mediastinum, where positron emission tomography showed accumulation of [(18)F] fluorodeoxyglucose. Selective venous sampling showed marked step-up in ACTH level in the internal thoracic vein but not in the cavernous sinus after CRH stimulation. These data are compatible with the diagnosis of EAS. The resected tumor was pathologically consistent with thymic neuroendocrine tumor (NET) positive for ACTH by immunohistochemistry and abundant V1b receptor gene expression by RT-PCR. Postoperatively, her circulating ACTH/cortisol levels became normalized, and responded to stimulation with CRH but not with desmopressin. Her Cushingoid appearance gradually disappeared, and she was free from recurrence 5 years after surgery. This is a rare case of desmopressin-responsive EAS caused by thymic NET with predominant V1b gene expression, which was successfully localized by imaging modalities combined with selective venous sampling.

Adrenocorticotropic hormone-producing thymic neuroendocrine carcinoma with oncocytic features: a case report and review of literature

Thymic neuroendocrine carcinomas are the most common mediastinal neuroendocrine tumor. These malignancies are not often diagnosed by fine-needle aspiration (FNA), as they are more commonly diagnosed by biopsy or excision. We describe a case of a FNA of a paratracheal mass from a 38-year-old man who presented with Cushing syndrome. A low-grade neuroendocrine carcinoma with oncocytic features was diagnosed, which was later confirmed by excision of the thymus, anterior mediastinal and paratracheal soft tissue, and lymph nodes. Oncocytic features in these tumors are a rare finding and bring metastatic medullary thyroid carcinomas as well as other metastases into the differential diagnosis. The prognosis of neuroendocrine carcinomas in this location is worse than neuroendocrine carcinomas in other areas, and close follow-up is recommended.

Thymic neuroendocrine carcinoma producing ectopic adrenocorticotropic hormone and Cushing's syndrome

Neuroendocrine carcinoma of the thymus, previously termed thymic carcinoid, is a rare clinical entity. Rarer still are such cases presenting with endocrinopathies. We report a case of thymic neuroendocrine carcinoma presenting with ectopic adrenocorticotroic hormone production and resultant Cushing's syndrome.

Neuroendocrine ACTH-producing tumor of the thymus--experience with 12 patients over 25 years

CONTEXT

ACTH-producing neuroendocrine tumor (NET) of the thymus is a rare cause of Cushing's syndrome (CS). The literature consists mainly of isolated case reports.

PATIENTS

We studied 12 cases (eight males and four females) diagnosed between 1986 and 2010 with CS and thymic NET who underwent surgical resection.

MAIN OUTCOME MEASURES

We measured time from onset of CS to diagnosis of thymic NET, tumor size, histological grade, time to recurrence, and survival and performed a meta-analysis of other published cases of CS associated with thymic NET.

RESULTS

Eleven of 12 patients presented with classic features of CS at a median age of 21 yr (range, 7-51). Four were children. The 24-h urine free cortisol was greater than 16-fold of normal, and biochemical testing was consistent with ectopic ACTH production in all 11. Another patient presenting with pulmonary embolus had a thymic mass and was later diagnosed with CS. All patients underwent thymectomy, and nine of 10 tumors exhibited positive ACTH immunochemistry. Median tumor diameter was 5 cm (range, 1-11.5). Six patients recurred 20-28 months after surgery with metastases to mediastinal lymph nodes (n = 5), bone (n = 5), liver (n = 1), parotid gland (n = 1), and breast (n = 1). Four of five patients treated with radiation therapy also received chemotherapy. All recurrent patients received ketoconazole; four later underwent bilateral adrenalectomy. Six recurrent patients died 22-90 months (median, 57) after thymectomy. At last review, six patients were alive 14-90 months (median, 49) after thymectomy. These data are similar to those from the meta-analysis.

CONCLUSIONS

Thymic ACTH-producing NET is an aggressive disease that should be considered in CS with ectopic ACTH secretion, particularly in younger patients.

Cushing's syndrome in a case of thymic carcinoma

A 29-year-old gentleman presented with episodic features suggestive of Cushing's syndrome. He was evaluated and diagnosed with ectopic Adrenocorticotropic hormone (ACTH)-dependent Cushing's syndrome due to a thymic tumor. The thymic lesion was excised and histopathology confirmed thymic carcinoma with neuroendocrine differentiation, with local, perineural, and vascular invasion. The postoperative problems and further treatment options have been discussed in this case report.

Ectopic ACTH syndrome associated with large cell neuroendocrine carcinoma of the thymus

A 38-year-old man was admitted for evaluation of Cushing's syndrome. Physical findings showed swelling of the face, and hypertension, but not Cushingoid stigmata. Laboratory data revealed serum cortisol level of 34.1 µg/dL and plasma ACTH of 140 pg/mL. Overnight administration of 1 and 8 mg dexamethasone did not suppress plasma ACTH or serum cortisol. Chest X-ray showed a mass at the upper-anterior quadrant of the mediastinum, and chest CT scan revealed a heterogenous tumor of approximately 60 mm in diameter, which infiltrated into the superior vena cava and ascending aorta, and caused superior vena cava syndrome. The tumor was resected. Histological examination indicated large cell neuroendocrine carcinoma of the thymus and positive immunoreactivity for ACTH. Ten days after the operation, the plasma ACTH decreased as low as 13.7 pg/mL. The present study indicates that large cell neuroendocrine carcinoma of the thymus can cause superior vena cava syndrome and ectopic ACTH syndrome.

Carcinoid tumor of the thymus associated with Cushing's syndrome and dysgeusia: case report and review of the literature

A 30-year-old man was hospitalized with edema, polyuria, and abnormalities in taste. ACTH and cortisol levels at admission were markedly elevated, even after attempted suppression with 8 mg dexamethasone. A thoracic-abdominal CT revealed an anterior mediastinal lesion and hyperplasia of both adrenal glands. After excision of the mediastinal mass, which confirmed the presence of a carcinoid thymic tumor, the patient became totally asymptomatic, with normal ACTH and cortisol levels. A carcinoid thymic tumor has a poor prognosis, especially when it is associated with Cushing's syndrome. Most patients will present recidivism or metastasis within 5 years after surgery. However, the low number of cases available for analysis makes it difficult to establish optimum therapeutic approaches.

Multiple pulmonary atypical carcinoids presenting with long-standing Cushing syndrome masked by pulmonary tuberculosis

Pulmonary neuroendocrine tumors, especially small cell carcinoma and typical carcinoids, are the most common cause of ectopic Cushing syndrome (CS). Sometimes these adrenocorticotropic hormone (ACTH)-producing tumors are too small to localize, and it may take a long time to identify them. This report describes the case of a 27-year-old-man with CS. This CS was due to the ectopic ACTH produced by the pulmonary atypical carcinoids, which were recognized at the disseminated stage 5 years after the initial presentation of CS. Microscopically, multiple whitish nodules (up to 1.0 cm in diameter) of the wedge-resected lung were composed of small round cells appearing to be typical neuroendocrine but were diagnosed as atypical carcinoid, based on the findings of focal necrosis, high mitotic rates and multiple endolymphatic tumor emboli. Immunohistochemically, tumor cells robustly stained for ACTH. The delay of diagnosis is, in part, attributable to the pulmonary tuberculosis (one of the complications of hypercortisolism), because the pulmonary tuberculosis presented in the form of multiple nodules throughout the lung. In addition, this patient had a Crooke's cell hyperplasia of the pituitary gland, which represents the reactive change of corticotrophs exposed to the excess cortisol rather than neoplastic change leading to CS.

Imaging in covert ectopic ACTH secretion: a CT pictorial review

The syndrome of ectopic adrenocorticotrophin secretion (EAS) is rare and is due to excess adrenocorticotrophin (ACTH) production from a nonpituitary tumour. These tumours can be covert, where the tumours are not readily apparent, and very small making them challenging to image. It is clinically and biochemically difficult to distinguish between covert EAS and Cushing's disease. The first-line investigation in locating the source of ACTH production is computed tomography (CT). The aim of this pictorial review is to illustrate the likely covert sites and related imaging findings. We review the CT appearances of tumours resulting in covert EAS and the associated literature. The most common tumours were bronchial carcinoid tumours, which appear as small, well-defined, round or ovoid pulmonary lesions. Rarer causes included thymic carcinoids, gastrointestinal carcinoids and pancreatic neuroendocrine tumours. Awareness of the imaging characteristics will aid identification of the source of ACTH production and allow potentially curative surgical resection.

Cytology of metastatic thymic well-differentiated neuroendocrine carcinoma (thymic carcinoid) in pleural fluid: report of a case

Thymic carcinoid tumors (well-differentiated neuroendocrine carcinomas) are uncommon anterior mediastinal neoplasms. These tumors are frequently accompanied by other endocrinopathies as part of a multiple endocrine neoplasia type I syndrome (MEN type I) and by paraneoplastic Cushing's syndrome and have a poor prognosis. We present the case of a 24-year-old man who presented for follow-up of thymic carcinoid with extensive bony metastases. He had recently completed radiotherapy to lesions involving his skull and mandible. An ultrasound-guided left-sided diagnostic and therapeutic thoracentesis was performed yielding 1 l of cloudy yellow fluid. The cytologic fluid preparations consisted of large "cannonballs" and atypical cell groups with salt and pepper nuclear chromatin. A panel of immunohistochemical stains were performed on the cell block material, and the atypical cells were positive for cytokeratin, synaptophysin, and chromogranin, but not for TTF1. These findings were consistent with metastatic well-differentiated neuroendocrine carcinoma (carcinoid tumor). This is the first reported case of a carcinoid tumor manifesting as large, spherical, smoothly contoured cell aggregates ("cannonballs") in a pleural fluid. Despite its rarity, a metastatic carcinoid tumor should be considered when "cannonballs" are found in effusions.

Carcinoid tumor and carcinoid syndrome

PURPOSE OF REVIEW

Carcinoid tumors secrete many different types of substances (e.g. serotonin, bradykinin) that may produce potentially fatal intraoperative reactions such as hypotension and bronchoconstriction. The most effective treatment for the deleterious cardiovascular and pulmonary effects of serotonin and bradykinin is octreotide, a somatostatin analogue. Carcinoid heart disease, which develops in the majority of patients with carcinoid syndrome, presents the anesthesiologist with more diagnostic and therapeutic dilemmas.

RECENT FINDINGS

The incidence of carcinoid tumors is much greater than previously recognized. New diagnostic techniques permit identification and localization of carcinoid tumors with greater accuracy. Short term and long term therapy with octreotide significantly improves survival and reduces the severity of 'carcinoid crises'. Echocardiographic studies have demonstrated a very high incidence of carcinoid heart disease (tricuspid and pulmonary insufficiency) in patients with carcinoid syndrome. Cardiac valve surgery is, consequently, becoming much more common in patients with carcinoid syndrome.

SUMMARY

More patients with carcinoid tumors and carcinoid syndrome are requiring anesthesia and surgery. Specific therapy with somatostatin analogues (octreotide) has replaced older less specific drugs (e.g. antihistamines) for the treatment of adverse effects caused by products of carcinoid tumors.

Six cases of ectopic ACTH syndrome caused by thymic carcinoid

The ectopic ACTH syndrome (EAS) caused by thymic carcinoid is rare and its diagnosis remains a challenge to the endocrinologist. Here are six cases of EAS with a typical Cushing habitus accompanied by hyperpigmentation and hypokalemia. For all six patients, the high dose (8 mg) dexamethasone suppression test (HDDST) showed lack of suppression, computed tomography (CT) scanning documented anterior mediastinal masses, and the mediastenal tumors removed were confirmed as ACTH secreting thymic carcinoids by positive ACTH and NSE staining. Our data indicate that HDDST chest radiologic imaging and other laboratory examinations will greatly assist in diagnosing the thymic carcinoid-induced EAS at an earlier stage, which will significantly improve the long-term survival of the patient.

Metastatic Thymic Carcinoid: A Case Report

Thymic neuroendocrine carcinomas (carcinoid) are rare tumors. They have malignant potential, the capacity for distant metastasis, and often present with associated endocrinopathies. This report describes a patient who was diagnosed with thymic carcinoid and Cushing syndrome at age 19 that, despite complete surgical excision of his tumor, developed local recurrence with distant metastases to his brain, lungs, and bone. We discuss the evolution of this patient's illness as well as the therapies used in his care. Due to the nature of these tumors to recur both locally and distant, the importance of aggressive surgical management is emphasized. We also discuss the role of adjuvant therapy, which in our case consisted of chemotherapy, radiotherapy, and several new therapies including an antiangiogenesis agent and a tyrosine kinase inhibitor.

Les tumeurs neuroendocrines du thymus

AIM

the aim of our study was to analyze a series of 6 thymic neuroendocrine tumors (TNET).

METHODS

we report the clinical and pathological features of 6 TNET reclassified according to the last WHO classification (2004).

RESULTS

there were 4 men and 2 women, (mean age of 61.3 years), presenting with local symptoms in 4 cases. The tumors were reclassified as 3 atypical carcinoids (AC), 2 small cell carcinomas (SCC) and 1 large cell neuroendocrine carcinoma (LCNEC). Cytokeratin, EMA and neuroendocrine markers were expressed in poorly-differentiated tumors. Two patients were lost of follow-up. Two patients with AC died of disease at 20 and 36 months. One patient with SCC died of disease at 2 years and the patient with the LCNEC died of disease in 3 months.

CONCLUSION

TNET are poor prognosis tumors with a prognosis similar to thymic carcinomas. Adequate surgical resection is a strong prognosis factor.

[18F]fluoro-2-deoxy-D-glucose ([18F]FDG) positron emission tomography imaging of thymic carcinoid tumor presenting with recurrent Cushing's syndrome

We report a case of a young woman with Cushing's syndrome (CS), in whom although endocrine investigations and negative pituitary imaging were suggestive of ectopic ACTH secretion, the results of inferior petrosal sinus (IPS) sampling after coricotropin-releasing hormone (CRH) stimulation were suggestive of pituitary ACTH hypersecretion. (111)In-labelled octreotide and high-resolution computer tomography (CT) revealed a lesion possibly responsible for the ACTH source in the thymus. Thymectomy confirmed concomitant ectopic CRH and probable ACTH production by a thymic neuroendocrine carcinoma. After an 8-year remission period the patient developed a clinical and biochemical relapse. A high-resolution computed tomography (CT) scan of the thorax showed a 2-cm nodule in the thymic bed, which was positive on a [(18)F]fluoro-2-deoxy-D-glucose ([(18)F]FDG) positron emission tomography (PET) scan. However, a repeated thymectomy did not result in remission. A repeat [(18)F]FDG PET study showed persistent disease in the thymic bed and also uptake in the adrenals. The patient underwent bilateral adrenalectomy, which resulted in clinical remission. A further [(18)F]FDG PET scan 8 months later showed no progression of the thymic tumor and confirmed complete excision of the adrenals. This is a rare case of concomitant CRH and ACTH secretion from a thymic carcinoid tumor; the case illustrates the usefulness of functional imaging with [(18)F]FDG PET in the diagnosis, management and follow-up of neuroendocrine tumors.

p53, cellular proliferation, and apoptosis-related factors in thymic neuroendocrine tumors

Thymic neuroendocrine tumors are biologically aggressive neoplasms with extensive local invasion and high mortality. Although various markers of cellular proliferation and apoptosis have correlated with degrees of tumor differentiation in pulmonary neuroendocrine neoplasms, they have not been systematically studied in thymic neuroendocrine tumors. We immunostained 21 cases of thymic neuroendocrine tumors for p53, MIB-1, and the apoptosis-related markers Bcl-2, Bcl-x, and Bax. By histological classification the cases were low-grade (nine cases), intermediate-grade (eight cases), and high-grade (four cases) thymic neuroendocrine tumors. p53 was expressed in five cases: 1/9 low grade, 3/8 intermediate grade, and 2/4 high grade. The mean cellular proliferation (MIB-1) was 7.1% (range 2-12%) in low-grade thymic neuroendocrine tumors, 6.1% (range 2-15%) in intermediate-grade thymic neuroendocrine tumors, and 34.2% (range 2-80%) in high-grade thymic neuroendocrine tumors. Bcl-2 was expressed in 16 cases: 7/9 low grade, 5/8 intermediate grade, and 4/4 high grade. Bcl-x was expressed in 16 cases: 7/9 low grade, 6/8 intermediate grade, and 3/4 high grade. Bax was expressed in 13 cases: 5/9 low grade, 4/8 intermediate grade, and 4/4 high grade. The presence of mutant p53 in the tumor was associated with a statistically significant decreased mean survival (P<0.05). In contrast, either by positive or negative staining or by the score technique (staining intensity x percentage of cells staining), the presence of Bcl-x was associated with an increased mean survival (P<0.05). Finally, a Bcl-x : Bax ratio >or=1 was also associated with an increased mean survival, as compared to a Bcl-x : Bax ratio >or=1 (P<0.05). Our study shows that p53 expression and certain apoptosis markers correlate with survival. The expression of these markers may account for differences in biological behavior.

Thymic atypical carcinoid with Cushing's syndrome manifesting in the terminal stage

A 56-year-old man with recurrent thymic atypical carcinoid presented with Cushing's syndrome only in the terminal stage. Eighteen months after the resection of an anterior mediastinal mass, he presented with hypernatremia and hypokalemia with high serum levels of adrenocorticotropic hormone and cortisol, and died two months later. An autopsy demonstrated multiple metastases of the tumor to the mediastinum, lungs, heart, liver, kidneys, bone, pituitary gland, and ocular muscles. The adrenocorticotropic hormone level of the tumor tissue was 26,000 pg/g.

Primary neuroendocrine tumors of the thymus

Primary neuroendocrine tumors of the thymus are highly aggressive tumors that rarely occur. A little more than 200 cases have been reported, many of which were single case reports. Only a few articles contained modest series from single centers for analysis. A review of 157 cases collected from the major series reported to-date show a clinical pattern with male preponderance (male:female ratio, 3:1) and a mean age of 54 years. Most patients presented with symptoms and signs of local compression. Almost 50% of these tumors were functionally active and were associated with endocrinopathies. Several histologic variants have been described, all with similar ultrastructural features. The biologic behavior of these tumors shows a direct relation to the degree of differentiation. Whenever possible, surgical resection is the treatment of choice as adjuvant therapy is controversial and has been used with variable success. Potential therapies exploit the presence of somatostatin receptors on a variety of these tumors. Use of radiolabeled Octreotide for radionuclide therapy has yielded tumor inhibition in animal models and may have clinical application. Fifty-one percent of the patients survived 3 years, 27% survived 5 years, and less than 10% survived beyond 10 years. Histologic grade, tumor extension, and early detection are the most important factors affecting survival. Other prognostic factors that impact outcome include presence of endocrinopathy, incomplete resectability, nodal status, and presence of distant metastasis.