Spindle-cell thymic carcinoid occurring in multiple endocrine neoplasia I: fine-needle aspiration findings in a case

Thymic neuroendocrine tumour in multiple endocrine neoplasia type 1: female patients are not rare exceptions

OBJECTIVE

Thymic neuroendocrine tumour (Th-NET) occurs in 2-5% of patients with MEN1 and has high malignant potency accompanying recurrence and distant metastasis. While Th-NET is recognized to develop predominantly in men and heavy smokers, a number of female patients have been reported in the literature. The objective of this study is to clarify the clinical features of MEN1 patients with Th-NET using database analysis.

DESIGN/PATIENTS

Clinical data of patients with Th-NET were extracted and analysed from a recently constructed database of Japanese MEN1 patients.

RESULTS

Among 560 registered cases, Th-NET was seen in 28 (5·0%) patients. Of note, 36% of patients (10/28) were women; only one patient among those was a smoker and another six patients were non-smokers. Age at diagnosis of Th-NET and MEN1, tumour size, prevalence of other MEN1-related tumours did not differ between male and female patients, and 10-year survival probability was 0·271 ± 0·106.

CONCLUSIONS

Although the prevalence of Th-NET in women (3·2%) is significantly lower than that in men (7·6%), a considerable proportion of female patients develop Th-NET. Given that Th-NET is a major determinant of life expectancy of patients, our results alert clinicians who treat patients with MEN1 that surveillance of Th-NET is essential even for female patients without a smoking habit.

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.

Distinguishing Carcinoid Tumor of the Mediastinum From Thymoma: Correlating Cytologic Features and Performance in the College of American Pathologists Interlaboratory Comparison Program in Nongynecologic Cytopathology

Context.—The cytologic features of carcinoid tumor in mediastinal fine-needle aspiration are well described. Nevertheless, this tumor may be difficult to distinguish from thymoma in this site.

Objective.—We sought to correlate the cytologic features of carcinoid tumor of the mediastinum in the College of American Pathologists Interlaboratory Comparison Program in Nongynecologic Cytopathology with the frequency of misclassification as thymoma.

Design.—We reviewed 446 interpretations from 18 different cases of carcinoid tumor in mediastinum and correlated the cytologic features with performance.

Results.—Cases were more frequently classified as thymoma (158 responses, 35%) than as carcinoid tumor (126 responses, 28%). The best-performing case was classified as carcinoid tumor only 56% of the time. Three cytologic patterns were identified. Four cases consisted of isolated round cells with salt-and-pepper chromatin. Four cases consisted of isolated spindle and round cells with salt-and-pepper chromatin. The remaining 10 cases consisted of cohesive fragments of crowded cells with finely granular chromatin showing numerous pyknotic cells mimicking lymphocytes. Prominent vasculature patterns were not a feature of any of the cases. There was no correlation between any pattern and the rate of classification as carcinoid tumor or thymoma (P > .05).

Conclusions.—Carcinoid tumor of the mediastinum is frequently misclassified as thymoma in this program. Although some cytologic patterns resemble thymoma, the lack of correlation of these patterns with performance suggests that at least part of the reason for misclassification may be failure to consider the correct diagnosis or a lack of familiarity with discriminating cytologic criteria.

Cytopathology of thymic epithelial neoplasms

A cytologic diagnosis of thymoma is extremely challenging. In part, this is because the tumor is uncommon and aspirates are infrequently encountered, a technically proficient interventional radiologist is needed, epithelial cells may be difficult to recognize in lymphoid rich aspirate smears, and there is inherent sampling error in a tumor that frequently displays heterogeneous histopathology. Critical to the cytologic diagnosis of most WHO Type B thymomas is the recognition of a distinct population of epithelial cells mixed with lymphocytes. This is more easily accomplished using Papanicolaou or H&E stains, and often requires a cytokeratin stain for verification (in the correct clinical-radiologic context) because these cells are cytologically bland and have a varying amount of cohesiveness. WHO Type A thymoma may contain only epithelial cells and thus mimic a spindle cell neoplasm, or mesothelial cell clusters. Limitations of the cytologic method include an unproven ability to definitively separate thymoma into specific WHO subtypes using cytology alone, and to determine capsular invasion. Non-neuroendocrine thymic carcinomas mimic their extra-thymic counterparts in cytologic aspirates, and their malignant nature is usually readily recognizable. Thymic neuroendocrine carcinomas (NEC) are also cytologically identical to their more common pulmonary sites of origin, but identification of moderately-differentiated NEC is generally not possible.

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.

Thymic carcinoids in multiple endocrine neoplasia-type 1

We report a case of a 45-year-old man with thymic carcinoids in multiple endocrine neoplasm-type 1. Extended total thymectomy was performed through a median sternotomy, and the mediastinal regional lymph nodes and fibroadipose tissue were dissected. Multiple endocrine neoplasm-type 1 related thymic carcinoids are rare and have a poor prognosis. The efficacy of radiotherapy and chemotherapy for prolonging survival is limited, and an aggressive surgical approach with complete excision of the tumor with resection of the peripheral tissues and dissection of the mediastinal lymph nodes seems to be the best available treatment today. We have found that this practice of thymectomy at an early stage in combination with genetic and effective radiological treatment can be effective for multiple endocrine neoplasm-type 1 patients.

Lipid-rich carcinoid tumor of the thymus gland: diagnosis by fine-needle aspiration biopsy

In this report we describe the cytologic features of an unusual thymic carcinoid tumor containing prominent cytoplasmic lipid vacuoles that was diagnosed by fine-needle aspiration biopsy. The tumor presented as a presternal subcutaneous mass in an 81-yr-old female, with a contiguous mediastinal mass on computed tomography. The cytomorphologic features included numerous discohesive cells with eccentric, round to oval nuclei, granular chromatin, and scant cytoplasm containing numerous intracytoplasmic, clear vacuoles. The neoplastic cells were reactive for neuroendocrine markers by immunocytochemistry and showed reactivity of the intracytoplasmic vacuoles with an oil red-O stain for neutral lipid. Ultrastructural examination confirmed the presence of intracytoplasmic lipid vacuoles and neurosecretory granules. Subsequent surgical excision confirmed the diagnosis. We believe this to be the first report describing these features in a primary thymic carcinoid tumor. The differential diagnosis of mediastinal tumors with clear-cell features and cytoplasmic vacuolization is also discussed.

Aspiration cytodiagnosis of small cell malignancies found in fine needle aspirate (FNA) of the liver: an immunocytochemical study

In this study the features of small cell malignancies found in the liver by fine needle aspiration cytology (FNAC) and immunostains required for a diagnosis and differential diagnosis are presented. The material consisted of 197 fine needle aspirates which were performed under image guidance between January 1982 to October 1999. Of these, 30 were diagnosed as small cell malignancies. The age of patients ranged between 46 and 68 years. The aspirated material was examined using Papanicolaou-stained filter preparations and cell blocks, the latter stained with hematoxylin and eosin and a panel of immunoperoxidase stains. The diagnoses based on a correlation of relevant clinical history, cytohistological findings and immunostaining were: metastatic small cell anaplastic carcinoma of lung (n = 6); neuroendocrine tumour (n = 9); non-Hodgkin's lymphoma (n = 4); well-differentiated cholangiocarcinoma (n = 2); metastatic carcinoma of the prostate (n = 2); metastatic adenocarcinoma (n = 4) and metastatic carcinoma breast (n = 3). This study emphasizes the wide range of neoplasms that enter into the differential diagnosis of small cell malignancies found in the liver and a correlation of clinical, cytohistological and immunostaining findings which seem to be useful in suggesting a diagnosis.

Application of the cell block method, utilizing mount quick mounting medium

Our objective was to determine the applicability of cell transfer and cell block methods using Mount Quick (Daido Sangyo, Saitama, Japan) mounting medium (MQ) for hematoxylin-eosin (H&E) and immunohistochemical staining of several limited amounts of biological materials in slide preparations. The materials investigated were histopathologically confirmed malignant mesotheliomas (pleural effusions) and malignant lymphomas, a malignant melanoma, and an amelanotic melanoma in sealed slides. Monoclonal antibodies against carcinoembryonic antigen (CEA), epithelial membrane antigen (EMA), cancer antigen 125 (CA-125), vimentin, thrombomodulin (TM), cytokeratin, UCHL-1, L-26, melanoma-specific antigen (HMB45), and S-100 protein (S-100) were applied in the investigation. The malignant mesotheliomas were found to be positive for EMA, cytokeratin, vimentin, TM, and CA-125, and negative for CEA, with no differences being observed in findings from direct contact preparations. Using T-cell-type malignant lymphomas for immunohistochemistry, UCHL-1 positivity and L-26 negativity were clearly demonstrated. The malignant melanoma and amelanotic melanoma materials stained strongly for HMB45 and S-100. Cell transfer employing MQ is a suitable approach for immunohistochemical investigations of limited materials. In addition, cell blocks derived from MQ-embedded smears can be used for both H&E and immunohistochemical staining. Diagn. Cytopathol. 2000;22:117-119.

Thymic carcinoids in multiple endocrine neoplasia type 1

OBJECTIVE

To study the clinical, pathologic, and genetic features of thymic carcinoids in the setting of multiple endocrine neoplasia type 1 (MEN1) and to study means for detection and prevention of this tumor in patients with MEN1.

SUMMARY BACKGROUND DATA

Thymic carcinoid is a rare malignancy, with approximately 150 cases reported to date. It may be associated with MEN1 and carries a poor prognosis, with no effective treatment. Its underlying etiology is unknown.

METHODS

Ten patients with MEN1 from eight families with anterior mediastinal tumors were included in a case series study at tertiary referring hospitals. Clinicopathologic studies were done on these patients, with a review of the literature. Mutation analysis was performed on the MEN1 gene in families with clusterings of the tumor to look for genotype-phenotype correlation. Loss of heterozygosity was studied in seven cases to look for genetic abnormalities.

RESULTS

Histologic studies of all tumors were consistent with the diagnosis of thymic carcinoid. Clustering of this tumor was found in some of the families-three pairs of brothers and three families with first- or second-degree relatives who had thymic carcinoid. All patients described here were men, with a mean age at detection of 44 years (range 31 to 66). Most of the patients had chest pain or were asymptomatic; none had Cushing's or carcinoid syndrome. All tumors were detected by computed tomography (CT) or magnetic resonance imaging (MRI) of the chest. The results of octreoscans performed in three patients were all positive. Histopathologic studies were consistent with the diagnosis of thymic carcinoid and did not stain for ACTH. Mutation analysis of the families with clustering revealed mutations in different exons/introns of the MEN1 gene. Loss of heterozygosity (LOH) studies of seven tumors did not show LOH in the MEN1 region, but two tumors showed LOH in the 1p region.

CONCLUSIONS

MEN1-related thymic carcinoids constitute approximately 25% of all cases of thymic carcinoids. In patients with MEN1, this is an insidious tumor not associated with Cushing's or carcinoid syndrome. Local invasion, recurrence, and distant metastasis are common, with no known effective treatment. We propose that CT or MRI of the chest, as well as octreoscanning, should be considered as part of clinical screening in patients with MEN1. We also propose performing prophylactic thymectomy during subtotal or total parathyroidectomy on patients with MEN1 to reduce the risks of thymic carcinoid and recurrence of hyperparathyroidism. Its male predominance, the absence of LOH in the MEN1 region, clustering in close relatives, and the presence of different MEN1 mutations in these families suggest the involvement of modifying genes in addition to the MEN1 gene. A putative tumor suppressor gene in 1p may be involved.

Diagnosis and differential diagnosis of small-cell lesions of the liver

The objective of this study was to evaluate the cytologic spectrum of small cell lesions of liver as diagnosed by fine-needle aspiration (FNA). Of 304 FNAs of liver that were performed in our institution between 1990 and 1994, 29 were classified as small-cell lesions. The final diagnoses were as follows: small-cell undifferentiated carcinoma (10), neuroendocrine carcinoma (9), cloacogenic carcinoma (1), Merkel-cell carcinoma (1), cholangiocarcinoma (1), metastatic adenocarcinoma (4), small-cell sarcoma (1), lymphoma (2). Relevant clinical history and immunocytochemistry were helpful in making the final diagnosis in some cases. The diagnosis and differential diagnosis of small cell lesions of the liver are discussed in detail in this report.

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.