Showing papers by "Saul Suster published in 2000"

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

Abstract: 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 highpower 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. The term carcinoid was introduced in 1907 by Oberndorfer 1 to designate a group of tumors in the small intestine that behaved less aggressively than conventional carcinomas. A few years later, Gosset and Masson 2 demonstrated the presence of argentaffin granules in the cells of these tumors and suggested that they were derived from Kulchitsky cells. In due time, the occurrence of these tumors in other anatomic areas was recognized. Rosai and Higa 3 were the first to acknowledge the existence of carcinoid tumors in the thymus and to separate them from more common tumors arising in this location, such as thymoma. Since then, numerous single case reports and short series of cases have been reported in the literature. 4-41 Although some previous studies seemed to indicate that carcinoid tumors arising in mediastinal location may behave more aggressively than their foregut counterparts, the true spectrum of histopathologic features and the range of clinical behavior of these lesions has not been analyzed in a large series of patients. We studied a large series of primary neuroendocrine carcinoma of the thymus (thymic carcinoids) in an attempt to correlate their morphologic features with their clinical behavior. Our results indicate that these tumors can display a broad range of cytologic features of atypia that generally are more pronounced than those observed in other foregut carcinoids. In addition, such tumors also are characterized by a more aggressive biologic behavior, justifying their inclusion within the spectrum of neuroendocrine carcinomas of the thymus.

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

Abstract: 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.

On the Histologic Heterogeneity of Thymic Epithelial Neoplasms Impact of Sampling in Subtyping and Classification of Thymomas

Abstract: Six hundred thirty cases of thymomas were evaluated to determine morphologic heterogeneity. The thymomas were grouped in 4 categories using previous terminology. Stratification according to the number of sections available for examination revealed a marked difference in distribution by histopathologic type. A cutoff number of 5 sections appears to provide a difference in subgrouping these tumors. In addition, the proportion of invasive tumors increases with the number of sections examined. Final classification may be affected by the extent of sampling. Histopathologic classification of thymoma, although of academic interest, may have limited practical relevance for assessment of prognosis in limited biopsy tissue. Proper evaluation of histology and aggressive potential in thymoma should be based on ample sampling and assessment of capsular integrity, which is best accomplished on thoroughly sampled resection specimens rather than incomplete or limited biopsy samples.