A phase II study evaluating the use of concurrent mitomycin C and capecitabine in patients with advanced unresectable pseudomyxoma peritonei.

Pseudomyxoma peritonei (PMP) is a rare neoplastic process characterised by progressive intra-abdominal dissemination of mucinous tumour, and generally considered resistant to systemic chemotherapy. A phase II study in patients with advanced unresectable PMP was undertaken to evaluate the combination of systemic concurrent mitomycin C (7 mg m(-2) i.v. on day 1) and capecitabine (1250 mg m(-2) b.d. on days 1-14) in a 3-weekly cycle (MCap). Response was determined by semiquantitative assessment of disease volume on serial computed tomographic (CT) scans and serum tumour marker (CEA, CA125, CA19-9) changes at 12 weeks. Between 2003 and 2006, 40 patients were recruited through a national centre for the treatment of peritoneal surface tumours. At baseline, 23 patients had progressive disease and 17 had stable disease. Of 39 assessable patients, 15 (38%, 95% confidence intervals (CIs): 25, 54%) benefited from chemotherapy in the form of either reductions in mucinous deposition or stabilisation of progressive pretreatment disease determined on CT scan. Notably, two patients, originally considered unresectable, following MCap and re-staging underwent potentially curative cytoreductive surgery. Grade 3/4 toxicity rates were low (6%, 95% CIs: 4, 9%). Twenty out of 29 assessed patients (69%, 95% CIs: 51, 83%) felt that their Global Health Status improved during chemotherapy. This is the first trial to demonstrate an apparent benefit of systemic chemotherapy in patients with advanced unresectable PMP.

A specific cadherin phenotype may characterise the disseminating yet non-metastatic behaviour of pseudomyxoma peritonei.

Pseudomyxoma peritonei (PMP) is a rare neoplasm of mainly appendiceal origin, characterised by excess intra-abdominal mucin production leading to high morbidity and mortality. While histological features are frequently indolent, this tumour disseminates aggressively throughout the abdominal cavity, yet seldom metastasises. This study determined the expression of several markers of colorectal differentiation (carcinoembryonic antigen (CEA), cytokeratins (CK20 and CK7), epithelial membrane antigen), mucin production (MUC-2, interleukin-9 (IL-9), IL-9 receptor (IL-9Ralpha)), and cell adhesion (N- and E-cadherin, vimentin) in PMP tissue (n=26) compared with expressions in normal colonic mucosa (n=19) and colorectal adenocarcinoma (n=26). Expressions of CEA and cytokeratins were similar for PMP as those in colorectal adenocarcinomas with the exception that the CK20-/CK7- pattern was rare in PMP (Fisher's exact test: P=0.001). Similarly, expressions of mucin-related proteins were comparable for adenocarcinoma and PMP, with the exception that IL-9 expression was uncommon in adenocarcinoma (P=0.009). Pseudomyxoma peritonei demonstrated a specific pattern of adhesion-related protein expressions of increased N-cadherin, reduced E-cadherin, and increased vimentin (P=0.004), a phenotype suggesting a possible epithelial-mesenchymal transition state. Primary PMP cell cultures were successfully maintained and demonstrated marker expressions similar to those seen in in vivo tissues. These early characterisation studies demonstrate similarities between PMP and colorectal adenocarcinoma, but also reveal a specific cadherin phenotype that may characterise the distinct non-metastasising behaviour of PMP, and form the basis for future mechanistic and therapy-targeting research.

Pseudomyxoma peritonei: unusual origin from an ovarian mature cystic teratoma.

Pseudomyxoma peritonei (PMP) is classified into pathologically and prognostically distinct categories, such as disseminated peritoneal adenomucinosis (DPAM) and peritoneal mucinous carcinomatosis. There is overwhelming evidence that DPAM arises from a mucinous adenoma of the appendix. The one exception to this is the presentation of a mature ovarian cystic teratoma as PMP where the appendix is normal. This report describes such a case and discusses the presentation, histopathology, and treatment options.

Pigmented mesenteric lymphadenopathy in familial adenomatous polyposis - an unusual cause of intraoperative abandonment of ileo-anal pouch.

Familial adenomatous polyposis (FAP) is an autosomal dominant condition with near complete penetrance, characterised by the presence of numerous adenomatous polyps of the colon and rectum. Melanosis coli describes the brownish-black discolouration of the colon resulting from the accumulation of a granular pigment in the phagosomes of macrophages in the colonic lamina propria. The presence of melanosis pigment in pericolonic lymph nodes has been reported in patients with coincidental melanosis coli, following segmental colonic resection. We report a unique case of FAP with melanosis pigment in lymph nodes in the small bowel mesentery that initially prevented a restorative proctocolectomy but that resolved following a colectomy, subsequently facilitating formation of an ileo-anal pouch.

Lymphoma in an ileostomy.

Lymphoma developing in an ileostomy is an extremely rare complication. The presentation is similar to the commoner, yet still rare, adenocarcinoma but the staging and management of the condition differs.