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Concordance of genetic alterations in poorly differentiated colorectal neuroendocrine carcinomas and associated adenocarcinomas.

BACKGROUND: The histopathologic spectrum of colorectal neuroendocrine tumors ranges from benign to highly malignant. In this spectrum, poorly differentiated neuroendocrine carcinoma (PDNC) is the most aggressive type, characterized by early dissemination and a rapidly fatal course. Since it is unclear whether PDNC originates from neoplastic transformation of preexisting neuroectodermal cells, pluripotent epithelial stem cells, or adenocarcinoma precursor cells, we investigated the histogenesis of this type of cancer by performing genetic analyses on a series of colorectal tumors. METHODS: Archived histologic sections of colorectal PDNC from nine patients were analyzed; gastrointestinal carcinoid tumor specimens from four patients were used as controls. The specimens were deparaffinized, microdissected, and analyzed genetically. After DNA extraction, polymerase chain reaction amplification was performed to investigate alteration (i.e., loss of heterozygosity [LOH]) of the APC (adenomatous polyposis coli), DCC (deleted in colorectal carcinoma), and p53 (also known as TP53) genes. RESULTS: LOH of the APC, DCC, or p53 genes was observed in six of eight informative PDNC tumors; no LOH was detected in the carcinoid control specimens. Four of five informative PDNC tumors had associated adenocarcinoma; LOH of the APC and p53 genes in these tumors involved the same allele in both tissue components. Four of the five tumors with associated adenocarcinoma showed LOH of the DCC gene; in three of these four tumors, the PDNC and adenomatous components showed LOH of the same allele. CONCLUSIONS: PDNC and associated adenocarcinoma appear to be derived from the same cell of origin, which is most likely either a pluripotent epithelial stem cell or an adenocarcinoma precursor cell.

Adenocarcinoma↗

Adenosquamous and squamous cell carcinoma of the colon.

Adenosquamous and squamous cell carcinomas of the colon are uncommon tumors; only 28 have been previously reported. In a review of 5,969 colonic adenocarcinomas (excluding anorectal cancers). I identified six carcinomas with squamous features. This is a frequency of 0.1% relative to the incidence of "usual" adenocarcinomas of the colon. An association of squamous neoplasia in the colon and chronic ulcerative colitis is noted.

Adenocarcinoma↗

Gastrointestinal glomus tumors: a clinicopathologic, immunohistochemical, and molecular genetic study of 32 cases.

Glomus tumors usually occur in the peripheral soft tissues, but similar tumors have also been reported in the stomach and occasionally in the intestines. However, the relationship of these tumors to peripheral glomus tumors and gastrointestinal stromal tumors has not been fully clarified because previous series of gastrointestinal glomus tumors predate availability of immunohistochemistry. This clinicopathologic study examined 32 gastrointestinal glomus tumors. All but one of the tumors were located in the stomach and the remaining tumor was from the cecum. The tumors occurred with a strong female predominance (23 females and 9 males) and a median age of 55 years (range 19-90 years). The gastric tumors typically presented with gastrointestinal bleeding or ulcer-like symptoms, and 14 tumors had mucosal ulceration. Five tumors were incidental findings. The tumor sizes varied from 1.1 to 7 cm (median 2 cm), and most were located in the antrum. Histologically, the tumors typically had a solid pattern of sharply demarcated, round glomus cells with prominent, mildly dilated pericytoma-like vessels. Vascular invasion and focal atypia were relatively common (seen in 11 and 13 cases, respectively), and low mitotic activity (1-4 per 50 high power fields), was seen in 10 cases. Immunohistochemically, all tumors were positive for alpha-smooth muscle actin and calponin, and nearly all had a net-like pericellular laminin and collagen type IV positivity. All tumors were negative for desmin and S-100 protein. Three tumors had focal synaptophysin positivity, but none was positive for chromogranin. All tumors lacked KIT expression and the GIST-specific mutations in the c-kit gene. Follow-up revealed one patient death of metastatic disease to liver at 50 months; this tumor had 1 mitosis per 50 high power fields, but had spindle cell foci, mild atypia, and vascular invasion. Thirteen patients were well and alive after long-term follow-up. Gastrointestinal glomus tumors occur almost exclusively in the stomach, and they have a good overall prognosis, but a small, unpredictable potential for malignant behavior exists. These tumors are phenotypically similar to peripheral glomus tumors and differ from epithelioid GISTs.

Actins↗

Jejunoileal arteriovenous malformation: localization for resection by segmental bowel staining techniques.

Arteriovenous malformations, submucosal vascular lakes, of the jejunum and ileum which cause chronic gastrointestinal bleeding and anemia are easily identified before operation by selective arteriography but difficult at operation owing to lack of physical signs. This report is concerned with a patient who had such a lesion located in the proximal jejunum. The involved segment was easily identified at operation by injection of Indigo Carmine solution during operation into the involved jejunal artery subselectively catheterized immediately prior to operation. The duration of jejunal staining before resection was 45 minutes in this case and varied from 35 to 55 minutes in five other patients who had right colectomy for carcinoma, providing the opportunity to inject accurately in a conveniently located radiology suite before operation. Safe, convenient, longer periods of staining which could be performed at the time of original diagnosis were demonstrated in dog experiments using "biologic" colloidal carbon in which the bowel segment was well stained at the time of sacrifice five days after injection. There were no gross or microscopic signs of injury to bowel.

Aged↗

Colonoscopy in the diagnosis of unexplained rectal bleeding.

Three hundred six patients with unexplained rectal bleeding were examined by colonoscopy. Significant lesions were found in 30% including polyps having a diameter of 0.5 cm or larger in 14%, carcinoma in 8%, and a small number of patients with inflammatory bowel disease, vascular formations, and radiation colitis. Colonoscopic findings in a large subgroup of patients with diverticulosis established by barium enema did not differ significantly from those of the group as a whole. Significant lesions were also identified in 22% of small subsets of patients with occult bleeding or unexplained melena.

Adenoma↗

Oophorectomy and colon cancer. Impact on survival.

Data on survival and survival free-from-recurrence were analyzed retrospectively in a group of 571 women who had undergone curative resection for colon cancer at the Mayo Clinic between 1972 and 1978. Of these women, 75 (group 1) had required bilateral oophorectomy before or at colon resection, while 496 (group 2) retained one or both ovaries. Average age, location and grade of tumor, and duration of follow-up were similar for both groups. Five-year-survival rate for the 571 women was 73.6%, as compared with 84.3% for matched controls. The 5-year survival rates were not significantly different for group 1 (78.0%) and group 2 (72.9%). Five-year survival free-from-recurrence also was not significantly different (82.9%, group 1 and 79.5%, group 2). Women in group 1 who had grade 1 or 2 tumors or lesions in the sigmoid and cecum fared the best (no significant difference from controls). Incidence studies of ovarian metastases from colon cancers suggest that three to eight per cent of women should benefit from bilateral oophorectomy. This agrees with the difference in survival observed between groups 1 and 2 in this study. Our sample size is too small to statistically confirm the reliability of this difference. The design of a prospective study testing this hypothesis is outlined.

Adult↗

Toxicity of irinotecan (CPT-11) and hepato-renal dysfunction.

Various clinical and laboratory parameters have been investigated for their ability to predict toxicity arising from the use of the anticancer drug, irinotecan (CPT-11). In particular, patients deficient in the conjugation of SN-38, a metabolite of CPT-11, are known to be at greater risk. We describe one case of a patient with metastatic colorectal cancer treated with a single dose of CPT-11 at 125 mg/m(2). Although this patient lacked any known predictive factors for toxicity, he experienced severe side-effects several days later. We hypothesized that the toxicity in this patient was due to compromised SN-38 conjugation. Plasma samples were analyzed by reversed-phase high-performance liquid chromatography assay for CPT-11 and its metabolites at 96, 144, 168, 192 and 288 h post-administration. We observed that the concentrations of both the parent drug and its metabolites were markedly raised (11- to 60-fold expected). Additionally the estimated terminal half-lives were 1.5-7 times those expected (29.5, 101, 39.6 and 41.8 h for CPT-11, APC, SN-38G and SN-38, respectively). We conclude that the toxicity in this patient was not caused by deficient SN-38 conjugation, but by decreased drug excretion through both hepatic and renal routes.

Adenocarcinoma↗

67Ga-citrate scanning in gastrointestinal malignancies.

The value of 67 Ga-citrate scanning in cases of gastrointestinal malignancies is discussed. Seven cases are presented, including lymphomas of the stomach, small bowel, and rectum, and adenocarcinomas of the stomach and colon. In a review of the literature, there is general pessimism regarding the use of 67Ga scans in GI malignancies. Based on previous reports and our own experience, specific clinical situations are cited in which the scan is of considerable value for diagnosis and followup of GI malignancy.

Adenocarcinoma↗

Detection of cecal adenocarcinoma by Tc-99m pertechnetate scintigram.

A 23-year-old male presented with occult gastrointestinal bleeding and iron deficiency anemia. A Tc-99m pertechnetate abdominal scan was positive and surgery revealed an adenocarcinoma of the cecum. No Meckel's diverticulum was identified. This is the first reported association of an abnormal Tc-99m pertechnetate scan in adenocarcinoma. Carcinoma of the right colon should be considered in any patient with a positive pertechnetate scan for Meckel's diverticulum and suggestive clinical features.

Adenocarcinoma↗