Management of the colonic polyps referred for surgery: an opportunity for improvement.

PURPOSE: To examine local practice for non-malignant polyps and to calculate morbidity and mortality associated with bowel resection for this indication. METHODS: This retrospective cohort study was conducted by reviewing our local gastrointestinal pathology database over a five-year period to identify colonic resections performed for benign polyps. Using search terms "polyp" and "adenoma," 272 cases were identified. Exclusion criteria included: cancer diagnosis, emergency surgeries, multiple resections, and subtotal colectomies for polyposis. 106 patients were included in the study. Primary outcome was perioperative mortality. Secondary outcomes included patient morbidity, characteristics of polyps requiring surgery, and the number of patients referred for a second endoscopic opinion prior to proceeding with surgery. RESULTS: 64 male and 42 female patients with a mean age of 65.3 years (± 8.6 years) underwent colon resection for benign polyps. The mean polyp size was 32.7 mm (± 19.5 mm). 30 patients (28.6%) had polyps equal to or less than 2 cm. Most of the polyps described were sessile (n = 55, 51.9%) and located in the right colon (n = 84, 79.3%). Endoscopic resection was attempted in 31 patients (29.2%), and five cases (4.7%) were referred for a second endoscopic opinion prior to proceeding with surgery. Endoscopists incorrectly felt that polyps were malignant in 62 cases (58.5%). Using Clavien-Dindo classification, most patients had no complications n = 36 (34.0%) or minor complications n = 41 (38.7%). Twelve patients (11.3%) had complications that required antibiotics, blood transfusions, or total parental nutrition. Nine patients (8.5%) required surgical or endoscopic management. Six patients (5.7%) required ICU admission. Mortality rate was 1.9% (n = 2). CONCLUSION: Surgery for benign colonic polyps is associated with significant morbidity and mortality. These findings reveal a gap in endoscopic management of benign colonic polyps.

Malignant mesothelioma in situ.

AIMS: The existence of malignant mesothelioma in situ (MIS) is often postulated, but there are no accepted morphological criteria for making such a diagnosis. METHODS AND RESULTS: Here we report two cases that appear to be true MIS on the basis of in-situ genomic analysis. In one case the patient had repeated unexplained pleural unilateral effusions. Two thoracoscopies 9 months apart revealed only visually normal pleura. Biopsies from both thoracoscopies showed only a single layer of mildly reactive mesothelial cells. However, these cells had lost BRCA1-associated protein 1 (BAP1) and showed loss of cyclin-dependent kinase inhibitor 2 (CDKN2A) (p16) by fluorescence in-situ hybridisation (FISH). NF2 was not deleted by FISH but 28% of the mesothelial cells showed hyperploidy. Six months after the second biopsy the patient has persisting effusions but no evidence of pleural malignancy on imaging. The second patient presented with ascites and minimal omental thickening on imaging, but no visual evidence of tumour at laparoscopy. Omental biopsy showed a single layer of minimally atypical mesothelial cells with rare tiny foci of superficial invasion of fat. BAP1 immunostain showed loss of nuclear BAP1 in all the surface mesothelial cells and the invasive cells. There was CDKN2A deletion, but no deletion of NF2 by FISH. CONCLUSIONS: These cases show that morphologically bland single-layered surface mesothelial proliferations with molecular alterations seen previously only in invasive malignant mesotheliomas exist, and presumably represent malignant MIS. More cases are need to understand the frequency of such changes and the time-course over which invasive tumour develops.

An unusual primary malignant tumor of the stomach: fetal gutlike gastric adenocarcinoma with "blastoma"-like component.

An unusual case of a polypoid, malignant gastric tumor in a 62-year-old man is presented. Endoscopy and subsequent polypectomy revealed an 8.5 × 6.5 × 4.5-cm lesion in the body of the stomach. Microscopy showed surface dysplasia with an invasive adenocarcinoma displaying prominent tubulopapillary areas composed of large vacuolated cells, pleomorphic nuclei, and occasional cytoplasmic hyaline globules. This component then blended with tubular structures lined by more primitive-appearing vacuolated cells embedded within a stroma made up of cellular primitive, high-grade blastemalike areas and less cellular, more pleomorphic foci with spindle and several bizarre, large cells. Immunohistochemistry showed the adenocarcinoma and primitive tubules to be strongly SALL4 and epithelial marker positive but with only focal expression of α-fetoprotein and glypican-3. The stromal component made up of blastemalike areas displayed strong immunoreactivity for glypican-3. The pleomorphic stromal areas were negative for all markers, including epithelial and muscle markers. The overall morphology and expression of primitive oncofetal proteins, especially SALL4 and glypican-3, are in keeping with this being a primitive adenocarcinoma showing fetal gutlike differentiation with an accompanying blastomalike component, a combination not previously described in a primary gastric cancer.

Evaluation of Hemo Techt NS-Plus system for use in a province-wide colorectal cancer screening program.

OBJECTIVES: The NS-Plus automated analyzer and fecal immunochemical testing (FIT) testing system (Alfresa Pharma) was evaluated for use in Newfoundland and Labrador's provincial colorectal cancer (CRC) screening program. DESIGN AND METHODS: Various method performance characteristics were evaluated including the sample stability. The sensitivity for detecting neoplastic lesions was evaluated in 249 patients scheduled for colonoscopy. Each patient collected up to 2 samples for both guaiac based testing (Hemoccult SENSA; gFOBT) and FIT using the NS-plus system (cutoff=20 µg Hb/g feces or 100 µg Hb/L) over 2 days. Data was analyzed comparing 1- and 2-day testing strategies. RESULTS: The analyzer showed acceptable linearity, precision, and accuracy. The collection device maintained acceptable sample stability for at least 7 days at: 37 °C, room temperature (~23 °C), 4-8 °C, and -20 °C. The 2-day sampling strategy identified 30% (21 of 69) of all neoplastic lesions (low and high grade adenomas and CRC) including 2 of 4 high-grade adenomas and 2 of 2 CRCs. The single day strategy identified the same high-grade adenomas and CRCs but fewer low-grade adenomas (23% of all neoplasia). Reducing the screening cutoff to the estimated 95th percentile of FIT results in the healthy adult population (10 µg Hb/g feces), detected all high-grade adenomas in the 2-day strategy. CONCLUSIONS: The NS Plus automated analyzer system detects clinically significant neoplasms and shows acceptable performance for use in a CRC screening program with the potential for gains in sensitivity by modifying the number of days of screening or through lowering the cutoff.

Plexiform fibrohistiocytic tumor: a brief review.

Plexiform fibrohistiocytic tumor is a rare mesenchymal neoplasm of intermediate malignancy, first reported by Enzinger and Zhang in 1988. It has a predilection for children and young adults but can occur at any age. The tumor usually involves the upper limbs as a slow-growing, painless mass. The tumor has a high local recurrence rate but metastasizes only rarely. Histologically, the tumor is characterized by poorly demarcated dermal or subcutaneous mass with multinodular plexiform growth and fibrohistiocytic cytomorphology. There are three distinct recognized growth patterns: fibrohistiocytic, fibroblastic, and mixed types. The tumor displays uniform immunoreactivity for vimentin and CD68. Ultrastructurally, the tumor cells have features of myofibroblasts and histiocyte-like cells. Complete surgical resection of the tumor, preferably with wider margins, is required to prevent local recurrence. Long-term follow-up is necessary to detect any nodal or pulmonary metastasis.