Solid pseudopapillary tumour

Abstract: Background: Solid-pseudopapillary tumors (SPTs) of the pancreas have been reported as rare lesions with “low malignant potential” occurring mainly in young women. This study was designed to define the clinicopathological characteristics and the effect of surgical intervention. Methods: A retrospective review from January 1985 to July 2000 was performed. Clinicopathological, operative, and survival data were obtained. The Kaplan-Meier method andχ 2 analysis were performed. All cases were re-reviewed by a senior pathologist. Results: During this time, 24 patients were diagnosed as having SPTs (0.9%). Twenty females and four males were identified, with a median age of 39 years (range, 12–79). The median size of the lesions was 8.0 cm (range, 1–20). Two patients’ tumors were found to be unresectable at initial presentation because of vascular invasion; both patients have remained alive with disease, one for 13 years and the other 1 year. At a median follow-up of 8 years, one recurrence occurred in 17 patients who underwent complete resection. Microscopic margin positive (P=.26), invasion of surrounding structures (P=.51), and size >5 cm (P=.20) were not significant predictors of survival. Four patients presented with synchronous liver metastasis and underwent resection of the primary tumor and the liver metastasis, with one patient dying of progression of metastatic disease at 8 months, another alive with recurrence in the liver at 6 years, and the last two alive without evidence of disease at 1 month and 11 years. Conclusions: SPT occurs predominantly in women (82%), although it can occur in men; all age groups are affected. Complete resection is associated with long-term survival even in the presence of metastatic disease.

Abstract: Solid-pseudopapillary tumor of the pancreas (SPT) has distinctive morphologic and biologic features but an unclear origin. It is classified among the pancreatic epithelial tumors, though many are reported to be negative for cytokeratin. Also unclear are its neuroendocrine differentiation, its capability to express alpha-1-antitrypsin (AAT) and, in view of the tumor's striking prevalence in women, its relationship with the female genital tract. To clarify these issues, the immunoprofiles of 59 SPTs were defined by applying a battery of antibodies against cytokeratin, vimentin, neuron-specific enolase (NSE), synaptophysin, chromogranin A, tyrosine hydroxylase (TH), AAT, LeuM1, Ki-M1P, smooth-muscle actin, CD34, alpha-inhibin, calretinin, placental alkaline phosphatase (PLAP), and progesterone and estrogen receptors. The most consistent markers with the strongest immunoreactivity were vimentin, AAT, NSE, and the progesterone receptor, which were each found in more than 90% of the tumors. Using immunocytochemical methods involving antigen retrieval, cytokeratin was demonstrated in almost 70% of the cases. Synaptophysin was found in 22% of the tumors, while chromogranin was absent and tyrosine hydroxylase was only present in a few tumors. None of the other markers tested were expressed by SPTs. This staining pattern fails to reveal a clear phenotypic relationship with any of the defined cell lineages of the pancreas. In view of the striking female preponderance of SPTs and the known close approximation of the genital ridges to the pancreatic anlage during embryogenesis, it is, however, hypothesized that SPTs might derive from genital ridge/ovarian anlage-related cells, which were attached to the pancreatic tissue during early embryogenesis.

Abstract: Solid pseudopapillary tumors (SPTs) are unusual neoplasms of the pancreas of uncertain histogenesis that occur mostly, but not exclusively, in young women. The pathologic features and immunophenotype of SPT are unique and well characterized. Despite its low malignant potential, proximately 15% of patients with SPT develop metastatic disease, mostly involving the liver or peritoneum. Even in the presence of disseminated disease, the clinical course is usually protracted, and the overall 5-year survival is reportedly 97%. We have encountered 2 cases of SPT possessing unusual pathologic features and exhibiting an aggressive clinical course. At the time of presentation, 1 patient had liver metastasis, and the other had a lymph node metastasis and developed liver metastases within 3 months. Both died of disease at 6 and 16 months, respectively, following the initial diagnosis. Review of other cases of SPT treated at Memorial Sloan-Kettering Cancer Center (New York, NY) revealed that 5 of 34 cases (15%) with conventional histologic features developed liver metastases. In contrast to the 2 cases reported here, all 5 patients survived for a mean of 106 months (39-193 months), and only 2 died of disease 5 and 10 years, respectively, following the initial resection. The pathologic features of the two rapidly fatal cases, which might have been indicative of their aggressive behavior, included a diffuse growth pattern, extensive tumor necrosis, significant nuclear atypia, an unusually high mitotic rate (35-70/50 high power fields), and in one a component of sarcomatoid carcinoma. However, regions displaying the typical histologic features of SPT were also evident. Abnormal beta-catenin distribution and markedly increased MIB1 expression were detected by immunohistochemistry in both cases. The immunohistochemical staining patterns were otherwise similar to those of conventional SPTs. Although precise pathologic criteria suggesting a high risk for aggressive behavior are uncertain, recognition of some of the unusual pathologic features displayed in these 2 cases may be useful in the prediction of potentially more aggressive SPTs. The possibility that these tumors represent high-grade malignant transformation of a conventional low-grade SPT is proposed.