The American journal of surgical pathology
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Am. J. Surg. Pathol. · Dec 2006
Comparative StudyComparison of microsatellite instability, CpG island methylation phenotype, BRAF and KRAS status in serrated polyps and traditional adenomas indicates separate pathways to distinct colorectal carcinoma end points.
The aim of this study was to compare BRAF and KRAS, CpG island methylator phenotype (CIMP), and microsatellite instability (MSI) status in each of the histologic categories, including end-point carcinomas with residual adenoma, of the serrated polyp neoplasia pathway and the traditional (nonserrated) adenoma-carcinoma sequence. Deoxyribonucleic acid (DNA) was extracted from the selected samples and assayed for BRAF, KRAS2 codon12, 13, CIMP using markers hMLH1, MGMT, MINT1, MINT2, p16, and MSI using an assay for BAT25 and BAT26. A BRAF mutation was present in 82% of serrated carcinomas (SCas), 62% of serrated adenomas (SAs), 83% of serrated polyps with abnormal proliferation (SPAPs-syn. sessile serrated adenoma [SSA]), 76% of microvesicular serrated polyps (MVSPs), and was not found in any of the histologic categories of the traditional adenoma-carcinoma sequence. ⋯ The findings indicate that a BRAF mutation is a specific marker for a serrated polyp pathway that has its origin in a hyperplastic polyp (MVSP) and a potential end point as MSI carcinoma. CIMP-High (CIMP-H) develops early in this sequence and MSI-H develops late. The data provided a less complete picture of a second serrated pathway, identified by a KRAS2 mutation in SAs, but showed that the progressive stages of both iterations of the serrated neoplasia pathway are separate and distinct from those of the traditional adenoma-carcinoma sequence.
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Am. J. Surg. Pathol. · Dec 2006
Intraductal papillary mucinous neoplasm (IPMN) of the pancreas: its histopathologic difference between 2 major types.
Intraductal papillary mucinous neoplasm (IPMN) is a unique pancreatic neoplasm developing in the ductal system. Two major histologic subtypes have been reported, that is the gastric type and the intestinal type. However, their histopathologic features, especially those of the gastric type, have not been fully described. ⋯ Seven cases (23%) of the intestinal type were associated with an invasive adenocarcinoma (6 mucinous and 1 ductal), versus only 1 case (2%) of the gastric type (invasive ductal carcinoma). All cases of both gastric and intestinal types expressed MUC5AC; however, high immunolabeling scores for MUC2 were mostly observed in the intestinal type (P<0.05). In conclusion, gastric and intestinal types of IPMNs have distinct histopathologic features and mucin profiles, suggesting that they may follow different biologic pathways.
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Am. J. Surg. Pathol. · Dec 2006
The incidence and anatomic site specificity of chromosomal translocations in primary extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) in North America.
Several balanced translocations have been identified in extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) but there are few data regarding their frequency in different anatomic sites or the frequency of translocations involving BCL6 or kappa or lambda immunoglobulin light chain genes (IGK or IGL), particularly in patients from geographic regions other than Europe and Japan. One hundred thirty-three paraffin-embedded North American primary MALT lymphoma specimens from diverse anatomic sites were studied by fluorescence in situ hybridization (FISH) using probes for API2-MALT1, IGH-MALT1, IGH-BCL10, IGH-FOXP1, IGH, +/- centromeres 3, 7, 12, and 18, and a subset (n=74) were analyzed using FISH probes for IGK, IGL, and BCL6. Translocations were mutually exclusive and were detected in 26% of cases (17% API2-MALT1, 5% IGH-MALT1, 3% IGH-unknown translocation partner, and 1% IGH-BCL10). ⋯ No MALT lymphomas with translocations involving IGK, IGL, BCL6, or FOXP1 were identified. This FISH panel detected cytogenetic abnormalities in half of all MALT lymphomas, and translocations arose preferentially in MALT lymphomas of the lung and gastrointestinal tract. Differences in incidence and anatomic site specificity of translocations between North American and non-North American cases may reflect geographic variability of infectious or other etiologic factors.
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Am. J. Surg. Pathol. · Nov 2006
Immunohistochemical analysis of INI1 protein in malignant pediatric CNS tumors: Lack of INI1 in atypical teratoid/rhabdoid tumors and in a fraction of primitive neuroectodermal tumors without rhabdoid phenotype.
Immunohistochemical lack of nuclear INI1 protein expression has been recently described as characteristic finding in atypical teratoid/rhabdoid tumors (AT/RTs), and has been suggested as useful marker to distinguish AT/RTs from other malignant pediatric central nervous system (CNS) tumors. In this study, we examined a large series of malignant pediatric CNS tumors to determine the immunohistochemical expression of INI1 protein in different malignant pediatric tumor entities. Archival paraffin-embedded biopsy specimens of 289 malignant pediatric CNS tumors including medulloblastomas, supratentorial primitive neuroectodermal tumors, glioblastomas, anaplastic astrocytomas, anaplastic ependymomas, choroid plexus carcinomas, germ cell tumors, and AT/RTs were analyzed immunohistochemically for expression of nuclear INI1 protein. ⋯ In summary, immunohistochemical expression of INI1 protein is lacking in tumors displaying characteristic morphologic features of AT/RT. Furthermore, a certain number of embryonal tumors without rhabdoid features but lack of INI1 protein and aggressive biologic behavior can be detected. We conclude that INI1 protein analysis should be routinely performed in all malignant pediatric embryonal CNS tumors to detect cases with lack of INI1 protein, because patients with these tumors are likely to benefit from intensified treatment.
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Am. J. Surg. Pathol. · Nov 2006
The recurrence and the overall survival rates of ovarian serous borderline neoplasms with noninvasive implants is time dependent.
Ovarian serous borderline neoplasm with noninvasive implants traditionally have been considered to be nonaggressive tumors associated with an excellent prognosis. However, in our experience, recurrences commonly develop as patients are followed over many years. Eighty cases of advanced-stage ovarian serous borderline tumor with noninvasive implants were identified; the minimum follow-up period for these cases was 5 years or until the death of the patient. ⋯ In this group of patients, 77% and 34% of the subsequent tumors developed 5 years and 10 years after diagnosis of the ovarian tumor, respectively. Histologic examination of the recurrent tumor is important in determining further therapy and prognosis for these patients; all patients who recurred with borderline tumor are without evidence of disease, whereas 74% of the patients who recurred with low-grade serous carcinoma died of disease. We propose that patients be followed for a minimum of 10 years to evaluate for recurrences and for 20 years to evaluate for survival.