Clinical and biological behavior of pancreatic solid pseudopapillary tumors: report on 31 consecutive patients.

BACKGROUND: Solid pseudopapillary tumors (SPTs) represent one of the most uncommon histotypes of all exocrine pancreatic neoplasms. AIM: To delineate the clinical presentation and biological behavior of SPT and evaluate the efficacy of treatment. METHODS: Retrospective analysis of 31 patients (27 female, 4 male, mean age of 34 years, (range 7-56)) who underwent surgical resection with a definitive histological diagnosis of SPT. RESULTS: Tumor detection was incidental in the 55% of cases. Symptoms were abdominal discomfort (n=10), jaundice (n=2), weight loss (n=6), vomiting (n=5), and a palpable abdominal mass (n=4). The neoplasm was localized in the pancreatic head in 10 patients and in the body-tail in 20 cases; the main diameter ranged from 2 to 20 cm (mean 5.4). At the radiological work-up, the neoplasm was solid in 87% of cases and delimited by a capsule in 39%. An internal necrotic-hemorrhagic area was present in 29% of cases. Calcifications were noticed in two patients and septa in one. None of the patients had metastases at the time of diagnosis. In 9 cases, pancreaticoduodenectomy was performed, while 15 patients underwent a left pancreatectomy (4 spleen preserving), 6 a middle pancreatectomy, and 1 enucleation. There was no postoperative mortality with an overall morbidity of 35%. At a median follow-up of 58.2 months (12-229 range), all patients are alive without evidence of local recurrence, metastasis, diabetes, or exocrine insufficiency. CONCLUSIONS: Solid pseudopapillary tumor (SPT) is an indolent neoplasm with low-grade biological aggressiveness, making surgical treatment successful despite its large size.

Constitutive expression of DeltaN-p63alpha isoform in human thymus and thymic epithelial tumours.

p63, a member of the p53 family, is involved in the survival and differentiation of reserve/stem cells in different epithelia. To unveil the possible role of p63 in thymic physiology and pathology, we investigated the expression of p63 isoforms in normal thymus, thymomas and other mediastinal tumours. All samples were analysed using immunohistochemistry with three different antibodies: 4A4 antibody recognising all p63 isoforms, p40 antibody reacting only with truncated dominant-negative isoforms (DeltaN-p63) and H-129 antibody recognising all alpha-isoforms. Reverse-transcription polymerase chain reaction (RT-PCR), and real-time PCR analyses were performed on RNA extracted from frozen samples of four thymomas and two primary-mediastinal large-B-cell lymphoma (PMLBCL). In normal thymus, DeltaN-p63alpha was expressed in all cortical and medullary epithelial cells, with decreasing intensity in Hassall's corpuscles. This phenotype was conserved in neoplastic transformation since all 54 investigated thymomas (World Health Organization types A, AB, B1, B2, B3, C) expressed DeltaN-p63alpha (virtually 100% cells). The predominance of DeltaN-p63alpha isoform mRNA was confirmed by real-time PCR. Among other mediastinal tumours, DeltaN-p63alpha was only expressed in those displaying either a stratified epithelial component (teratomas) or epidermoid differentiation (lung carcinoma). Among lymphomas, T-cell-precursor lymphomas did not express p63, whereas most PMLBCL expressed TA-p63alpha (7/8).