Carcinoid of the thymus with hereditary hyperparathyroidism

A case of madness resulting in a fortunate outcome; case report of a psychotic break as a result of cortisol secreting thymic neuroendocrine thymic tumor

Representing a mere 2–5% of the total thymic malignancies and 0.4% of total carcinoid tumors, primary thymic neuroendocrine tumors (NETs) are the zebras of the thymic neoplasms. They were initially characterized as ‘epithelial thymomas’; later, the term carcinoid tumors was coined by Rosai and Higa. These tumors are highly unpredictable in their presentation and prognosis. Coupled with variable clinical presentation, rare pathologic diagnosis and absence of diagnostic and prognostic parameters, it is a challenge for both patients and clinicians. Treatment entails local definitive therapy, symptom control and systemic chemoradiation given either pre or post operatively based on staging and resectability. We hereby report a peculiar case of psychosis that likely resulted from one such rare tumor.

Thymic neuroendocrine tumors in multiple endocrine neoplasia type 1: a comparative study on 21 cases among a series of 761 MEN1 from the GTE (Groupe des Tumeurs Endocrines)

BACKGROUND

Thymic neuroendocrine tumors (Th-NET) present a poor prognosis for patients with multiple endocrine neoplasia type 1 (MEN1). The purpose of this article was to study the clinical, biological, and pathological features of Th-NET in a large cohort of patients with MEN1.

METHODS

The 761-patient MEN1 cohort from the GTE registry was used (Groupe des Tumeurs Endocrines).

RESULTS

The actuarial probability of occurrence was 2.6% (range, 1.3-5.5%) at aged 40 years. All, except one, Th-NET patients were men. Four patients had no other associated lesions. The youngest patient was aged 16 years. Mean age at the time of diagnosis was 42.7 (range, 16.1-67.5) years. The 10-year probability of survival was 36.1% (range, 11.5-62%). Seven patients (33%) belonged to clustered MEN1 families. The spectrum of associated lesions in patients with Th-NET was not statistically different from the spectrum of the remainder of the cohort. Various endocrine markers were high, but none were sensitive or specific enough to be useful for Th-NET detection. CT-scan and MRI were always positive at the time of diagnosis. No particular mutation was found to be associated with Th-NET. Five cases underwent prophylactic thymectomy without success.

CONCLUSIONS

Several end points may be helpful for future guidelines: (1) earlier detection of Th-NET in MEN1 patients is required; (2) screening of both sexes is necessary; (3) a prospective study comparing MRI vs. CT scan in yearly screening for Th-NET is needed; (4) a reinforced screening program must be established for patients who belong to clustered families; and (5) thymectomies must be performed in specialized centers.

Neuroendocrine carcinomas (carcinoid, atypical carcinoid, small cell carcinoma, and large cell neuroendocrine carcinoma): current concepts

Neuroendocrine carcinomas are ubiquitous neoplasms that may occur anywhere in the human body. A unifying concept regarding the classification of these tumors has been controversial. Although most neuroendocrine neoplasms occur in the gastrointestinal tract, current concepts regarding classification and nomenclature are being driven by studies of thoracic tumors. One issue that has been put forward to keep separate nomenclatures for these tumors in different organ systems is the different clinical behavior of these neoplasms in different systems. The most important aspect regarding this group of tumors is the fact that they should be considered neoplasms capable of local recurrence and distant metastasis. Close clinical correlation and appropriate treatment are important to improve the survival rate in this group of patients.

Primary neuroendocrine carcinomas of the mediastinum: review of current criteria for histopathologic diagnosis and classification

Primary neuroendocrine neoplasms occurring in the mediastinum are rare. The spectrum of such tumors can range from low- to high-grade neoplasms. The histogenesis of these tumors is varied, and some of them may originate from ectopic tissues in the mediastinum whereas others represent tumors native to the thymus. Primary thymic neuroendocrine carcinomas therefore need to be separated from other neuroendocrine neoplasms of the mediastinum, namely ectopic parathyroid tumors and paragangliomas. The histopathologic classification of primary neuroendocrine carcinomas of the mediastinum is still under debate and continues to be controversial, as is attested to by the different publications on the topic. Some authors continue to use old terms such as "carcinoid" and "atypical carcinoid" to designate these lesions, whereas others favor the use of a more unifying nomenclature that acknowledges the malignant nature of these lesions, namely that of neuroendocrine carcinoma. However, one aspect that all agree on is that, when they occur in the thymic region, these tumors should be considered as aggressive neoplasms capable of local recurrence and distant metastasis. This review will center on the morphologic spectrum of neuroendocrine carcinomas of the thymus, with special emphasis on diagnostic features and criteria for classification.

Prospective study of thymic carcinoids in patients with multiple endocrine neoplasia type 1

Little is known of the natural history of thymic carcinoids in multiple endocrine neoplasia type 1 (MEN1). This is important because in 1993 they were identified as a frequent cause of death, yet only small retrospective studies and case reports exist. We report results of a prospective study of 85 patients with MEN1 evaluated for pancreatic endocrine tumors and followed over a mean of 8 yr with serial chest computed tomography, magnetic resonance imaging (MRI), chest x-ray, and, since 1994, octreoscans [somatostatin receptor scintigraphy (SRS)]. Seven patients (8%) developed thymic carcinoids. Patients with and without carcinoids did not differ in clinical, laboratory, or MEN1 tumor features, except for male gender and the presence of a gastric carcinoid. All thymic tumors were hormonally inactive. Four thymic carcinoids lacked 11q loss of heterozygosity, although it was found in three pancreatic endocrine tumors. Computed tomography and/or MRI were more sensitive than SRS or chest x-ray in detecting tumors initially or with recurrence. All patients underwent resection of the thymic carcinoid, and in all patients followed more than 1 yr, the tumor recurred. Bone metastases developed in two patients and were detected early only on MRI, not SRS. This study provides information on early thymic carcinoids and allows modifications of existing guidelines to be recommended for their diagnosis, surveillance, and treatment.

Neuroendocrine carcinomas (carcinoid tumor) of the thymus. A clinicopathologic analysis of 80 cases

We studied 80 cases of primary thymic neuroendocrine carcinomas. Most patients had symptoms; approximately one third were asymptomatic. All cases were treated by surgical excision. The tumors were divided according to histopathologic features into low- (n = 29), intermediate- (n = 36), and high-grade (n = 15) types. The tumors displayed a variegated histologic appearance and unusual cytologic features. Some cases showed transition from low to high grade within the same tumor mass. Mitotic activity ranged from fewer than 3 to more than 10 mitotic figures per 10 high-power fields, and most tumors displayed marked cellular atypia and areas of necrosis. In 73 patients, the tumor was confined to the anterior mediastinum. Positive immunohistochemical reaction was observed using antibodies for CAM 5.2 low-molecular-weight cytokeratins, broad-spectrum keratin, chromogranin, synaptophysin, and Leu-7. The clinical follow-up obtained in 50 patients correlated well with tumor differentiation. Therefore, the behavior of these tumors seems to correlate with histologic grade, which seems directly proportional to degree of differentiation. We propose replacing the term thymic carcinoid with thymic neuroendocrine carcinoma, which better reflects the aggressive biologic behavior of these tumors in the mediastinal location.

Primary neuroendocrine carcinoma (thymic carcinoid) of the thymus with prominent oncocytic features: a clinicopathologic study of 22 cases

Twenty-two cases of oncocytic thymic neuroendocrine carcinomas (carcinoid tumors) are presented. The patients were 17 men and 5 women between the ages of 26 and 84 years (median, 55 years). Nine were asymptomatic, and the tumor was found on routine examination; four patients presented with chest pain, two with weight loss, two with multiple endocrine neoplasia I syndrome, and one with Cushing's syndrome. Surgical resection of the mediastinal tumor was performed in all cases. The lesions were described as soft, light tan to brown, measuring from 3 to 20 cm in greatest diameter. On cut section, the tumors showed a homogeneous surface, soft consistency, and focal areas of hemorrhage. Microscopically, the lesions were characterized by nests or trabeculae of tumor cells that contained abundant granular to densely eosinophilic cytoplasm, with round to oval nuclei and in some areas prominent nucleoli. Mitotic figures ranged from 2 to 10 per 10 high-power fields; foci of comedonecrosis were seen in all cases. Immunohistochemical studies including broad spectrum keratin, CAM 5.2, chromogranin, synaptophysin, Leu-7, and p53 were performed in 12 cases. All of the tumors were strongly positive for CAM 5.2 low-molecular-weight cytokeratin, 11 showed strong positive reaction for Leu-7, 10 for broad-spectrum keratin, 8 for chromogranin, 7 for synaptophysin, and only 1 case showed focal positive staining of the tumor cells for p53. Clinical follow-up of 14 patients showed that 10 were alive between 2 and 11 years, and 4 patients had died of tumor from 4 to 11 years after diagnosis. Patients with good clinical outcome were those whose tumors showed low mitotic activity and minimal nuclear pleomorphism, whereas those who had died of their tumors were those whose tumors were characterized by marked nuclear atypia and higher mitotic rates. Oncocytic thymic carcinoids should be added to the differential diagnosis of anterior mediastinal neoplasms characterized by a monotonous population of tumor cells with prominent oncocytic features.

Thymic neuroendocrine carcinomas with combined features ranging from well-differentiated (carcinoid) to small cell carcinoma. A clinicopathologic and immunohistochemical study of 11 cases

We reviewed 11 cases of primary thymic neuroendocrine carcinomas with combined features ranging from well-differentiated to poorly differentiated neuroendocrine carcinoma. For 3 asymptomatic patients, tumors were discovered during routine examination. Presentation in the other patients was as follows: Cushing syndrome, 2 patients; chest pain, 3 patients; superior vena cava syndrome, 1 patient; and hypercalcemia and hypophosphatemia, 1 patient. No clinical data were available for the 11th patient. All tumors were located in the anterior mediastinum and treated by surgical excision. The lesions were large and well-circumscribed with areas of hemorrhage and necrosis. They were characterized by areas showing a proliferation of monotonous, round tumor cells adopting a prominent organoid pattern admixed with areas showing sheets of atypical cells with hyperchromatic nuclei, frequent mitoses, and extensive areas of hemorrhage and necrosis. Immunohistochemical studies performed in 6 cases showed strong CAM 5.2 low-molecular-weight cytokeratin positivity in all cases, chromogranin and synaptophysin positivity in 4, Leu-7 in 3, and focal positivity for p53 in 2. Follow-up information for 9 cases showed that all patients died of their tumors between 1 and 4 years after diagnosis. The present cases highlight the heterogeneity of neuroendocrine neoplasms and reinforce the notion that these tumors form part of a continuous spectrum of differentiation.

Angiomatoid neuroendocrine carcinoma of the thymus: report of a distinctive morphological variant of neuroendocrine tumor of the thymus resembling a vascular neoplasm

Three cases of primary thymic neuroendocrine tumors characterized by prominent angiomatoid features that resembled a vascular neoplasm are presented. The patients were all men between 52 and 59 years of age who presented with chest pain and shortness of breath attributable to a large anterior mediastinal mass. The lesions ranged in size from 6 cm to 15 cm in greatest diameter, and were grossly soft and well circumscribed, but not encapsulated. The cut surface was remarkable for multiple blood-filled cyst-like spaces admixed with focal solid, hemorrhagic areas. Histologically, the tumors contained multiple cystically dilated spaces filled with blood which imparted the lesion with a striking angiomatoid appearance. The walls of the cysts were lined by a monotonous proliferation of round to oval cells with distinct cell borders, round central nuclei, and abundant eosinophilic cytoplasm. Mitotic activity was present in all cases and varied from 3 to 8 mitoses per 10 high-power fields. Immunohistochemical studies performed in two cases showed positivity of the tumor cells for keratin, Leu 7, and synaptophysin, and focal chromogranin positivity in one. Follow-up information obtained in two patients showed that both had died of tumor 4 and 8 years after initial diagnosis. The present cases show an unusual morphological appearance of thymic neuroendocrine tumors that may be mistaken for a vascular neoplasm. Immunohistochemical stains may be of importance in such instances in arriving at the correct diagnosis.

Thymic carcinoids in multiple endocrine neoplasia type 1

Thymic carcinoid is a rare malignancy with about 150 cases reported to date. It is associated with multiple endocrine neoplasia type 1 (MEN-1), but compared with other MEN-1-related neoplasia little is known about it. We have recently described and studied 20 MEN-1-related cases and found that up to 25% of all reported thymic carcinoids are MEN-1 related. It is an insidious tumour not associated with Cushing's syndrome or carcinoid syndrome. Local invasion, recurrence and distant metastasis are common with no known effective treatment. Its male predominance, the absence of loss of heterozygosity (LOH) in the MEN1 region, clustering in some MEN-1 families and the findings of different MEN1 mutations in these clustered families suggest the involvement of additional aetiological factors. We propose that computed tomography (CT) or magnetic resonance imaging (MRI) of the chest should be included as part of the clinical workup for all MEN-1 patients. Prophylactic thymectomy should be considered during subtotal or total parathyroidectomy on MEN-1 patients to reduce the risk of this malignancy.

Clinicopathologic studies of thymic carcinoids in multiple endocrine neoplasia type 1

Thymic carcinoid is part of the multiple endocrine neoplasia type 1 (MEN1) syndrome occurring predominantly in male patients who were heavy smokers, presenting most commonly in middle age. In contrast with metastatic midgut carcinoids, MEN1-related thymic carcinoid is not associated with carcinoid syndrome, nor is it associated with Cushing syndrome, in contrast with sporadic thymic carcinoids. Local invasion and metastasis are common. Prognosis is poor because of late detection, lack of effective treatment, and the aggressive nature of the tumor. All patients with thymic carcinoids should be investigated for MEN1, including thorough clinical evaluation and family studies. Anterior mediastinal lesions in MEN1 male patients should be considered thymic carcinoids until proven otherwise. All male MEN1 patients and asymptomatic gene carriers should be warned of the risk of thymic carcinoids and the possible link to smoking. Computed tomography (CT) of the chest is recommended on first screening for MEN1 in male patients more than 25 years of age, followed by yearly chest X-rays and chest CT every 3 years. Prophylactic thymectomy should be carried out during subtotal or total parathyroidectomy on MEN1 patients.

Parathyroid hyperplasia associated with thymoma

The case of a 65 year old female with myasthenia gravis and hypercalcaemia is presented. Failure of medical control of the myasthenia necessitated thymectomy at which time parathyroid exploration was also carried out. This revealed parathyroid hyperplasia and a thymoma. This association has not been previously documented in the literature.

Ileal carcinoid tumor complicated by retroperitoneal fibrosis and a prolactinoma

A patient with mid-gut carcinoid tumor and the unusual complication of retroperitoneal fibrosis was also found to have a prolactinoma. This case brings the number of reported mid-gut carcinoid tumors complicated by a second endocrine neoplasm to five. Three of the second tumors were parathyroid in origin, and the fourth was an insulinoma. In view of the rarity of second tumors and in the absence of documented familial occurrence, it is inappropriate to exhaustively study each person with mid-gut carcinoid tumor, or their families, for a second endocrine neoplasm; however, physicians caring for patients with mid-gut carcinoid should be aware that second tumors are possible. Retroperitoneal fibrosis is also a rare complication of carcinoid, but can be associated with renal failure that can be prevented by surgical intervention. Thus, physicians caring for patients with the carcinoid syndrome should also be aware of this complication.

Neuroendocrine neoplasms of the thymus

Neuroendocrine tumors of the thymus bear many similarities to "carcinoids" and "oat-cell carcinomas" in other organs, and are clinicopathologically distinct from thymomas, thymic seminomas, and other primary tumors of this gland. They are associated with Cushing's syndrome or multiple endocrine neoplasia in 35% of cases, and are often locally aggressive. Approximately 30-40% of patients have distant metastases of their tumors that ultimately result in fatality, since the response of thymic neuroendocrine neoplasms to irradiation and chemotherapy is poor. Ultrastructural studies and immunohistochemical stains for chromogranin, protein gene product 9.5, and synaptophysin are effective tools for the diagnosis of thymic carcinoid and oat-cell carcinoma.

Carcinoid tumor of the thymus

Primary carcinoid tumor of the thymus is a rare, slow-growing neoplasm occurring most commonly in middle-aged men. The usual clinical manifestations are those of a mediastinal mass, although in asymptomatic patients, the diagnosis may be suggested by a routine chest roentgenogram. Excision is the most common treatment. Because the disease may recur up to ten years after surgery, follow-up is important. The case reported here is of a 49-year-old man who was hospitalized for evaluation of a mediastinal mass first detected six years previously. When laboratory and other tests proved nondiagnostic, thoracotomy was done and pathologic examination of the excised mass revealed carcinoid tumor of the thymus.

Concomitant hepatic radiation and intraarterial fluorinated pyrimidine therapy: correlation of liver scan, liver function tests, and plasma CEA with tumor response

Sixteen patients with metastatic disease to the liver (12 colorectal and four unknown primary tumors) were treated in a pilot study of hepatic irradiation (2500-3000 rads in 10-12 fractions) delivered concomitantly with continuous short-term intraarterial infusion of 5-fluorouracil (1 g/d) or FUDR (0.5 mg/kg/d) via a percutaneously placed hepatic artery catheter. Abnormal liver function tests, including SGOT, LDH, and alkaline phosphatase, decreased in all patients by day 7-10 of treatment, and other metabolic factors, including serum cholesterol, calcium, albumin, phosphorous, and uric acid, also decreased, often to subnormal levels by termination of treatment (day 15-20). These chemical alterations did not correlate with tumor response in that the identical pattern was observed in responders (ten patients) as well as nonresponders (six patients). Objective determinants of response were assessed by serial monitoring of the plasma carcinoembryonic antigen (CEA) and liver scan. In 14 patients with elevated CEA levels, tumor response (nine patients), nonresponse (four patients), and relapse (five patients) was predicted and confirmed by sequential monitoring of CEA. In one patient, a paradoxical decrease in plasma CEA was associated with progressive disease. The liver scan identified all responding patients but was difficult to quantitate and was delayed for months following subjective clinical response and changes in plasma CEA levels.