Peritoneal melanosis associated with mucinous cystadenoma of the ovary and adenocarcinoma of the colon.

Peritoneal melanosis, a diffuse, black pigmentation of the peritoneum, is a very rare condition characterized by melanin pigment deposition in the peritoneum. In this paper, we describe a case of peritoneal melanosis associated with a mucinous cystadenoma on an ovary and adenocarcinoma in the colon of 68-year-old women. The patient was referred for an evaluation of lower abdominal pain and distension. Laboratory results showed anemia and elevated CA 125 levels. A pelvic computed tomographic scan revealed a huge multicystic mass on the right ovary and a well-enhancing intraluminal mass located at the rectosigmoid junction. During a surgical procedure, India-ink-colored (black) pigmentation was seen in the peritoneum, in the omentum, and on the surface of the ovary. Biopsies of the omentum and peritoneum showed pigment in the stroma and pigment-laden histiocytic aggregation. Pigment was also present in the wall of the mucinous cystadenoma of the ovary and colonic serosa. An ultrastructural study found melanosome in the cytoplasm of the histiocytes.

Histology of the mucosa in sigmoid colon specimens with diverticular disease: observations for the interpretation of sigmoid colonoscopic biopsy specimens.

We examined retrospectively 100 sigmoid colon resection specimens removed for diverticulitis (DD [diverticular disease]-diverticulitis), 53 adenocarcinoma specimens that also had diverticulosis (DD-adenocarcinoma), and 50 adenocarcinoma specimens that did not have DD (adenocarcinoma only) to study the mucosal changes that occur in DD. Documenting these histologic features could be helpful in deciphering changes seen in colonoscopic biopsy specimens from the sigmoid colon in older patients. Prominent mucosal folds were present in approximately 90% of all DD specimens. Increased mucosal lymphoplasmacytic inflammation at the bases of the prominent folds was present in 15% and 9% of DD-diverticulitis and DD-adenocarcinoma specimens, respectively. Eleven percent of the DD-diverticulitis and 4% of the DD-adenocarcinoma specimens had prolapselike mucosal abnormalities of the mucosa on the surface of the prominent mucosal folds. Mildly increased lymphoplasmacytic inflammation surrounded the diverticulosis ostia in approximately 25% of all DD specimens. All the diverticulitis ostia had neutrophilic and lymphoplasmacytic inflammation in the surrounding mucosa. No specimens had crypt distortion. Diverticular disease-related inflammation may be one cause of mild patchy inflammation that is occasionally observed in sigmoid colon biopsy specimens. Diverticular disease also should be considered as a cause of mucosal prolapse changes in sigmoid colon biopsy specimens. Other diseases should be considered when markedly increased mucosal inflammation, crypt distortion, or granulomas are present. Distinction between a DD-related incidental finding and a significant pathologic abnormality frequently can be made with the procurement of multiple biopsy specimens.

["Serrated" adenoma--a little known type of colorectal tumors]. / Fogazott ("serrated") adenoma--a colorectalis daganatok kevéssé ismert tpusa.

Eight cases and review of the literature on serrated adenoma of the colon were reported. This distinct entity of colorectal tumors was described in recent years. The tumors contain hyperplastic and adenomatous areas. Their tendency for malignant transformation is similar to pure adenomas to contrary to benign hyperplastic polyps. Three tumors of eight reported cases were pedunculated, while five were sessile. Four patients were operated on because of narrowing of intestinal lumen by the tumors. Malignant transformation of tumors was observed in three cases. Several biopsies were performed before major operations. Histology showed false benign hyperplastic tumors. Importance of multiple tissue sample for histology was emphasised. Electron microscopy showed disturbed differentiation and pathological mucus production of tumor cells.

Cronkhite-Canada syndrome. Light and electron microscopy of the cutaneous pigmentary abnormalities.

This article describes the light and electron microscopic studies from a macule and the surrounding lightly hyperpigmented skin of a patient with the Cronkhite-Canada syndrome. Increased numbers of melanin granules in keratinocytes, increased numbers of melanosomes in melanocytes, and areas with increased numbers of melanocytes were found in the macular lesion. Skin from both the macule and surrounding area were also characterized by compact hyperkeratosis as well as perivascular inflammation and exocytosis not previously reported in these patients.

Pleomorphic (giant cell) carcinoma of the intestine. An immunohistochemical and electron microscopic study.

Pleomorphic (giant cell) carcinomas have been described in the lungs, thyroid, pancreas, and gallbladder. Two pleomorphic carcinomas of the small bowel and two of the large bowel are presented. On light microscopic study, the carcinomas were solid, without squamous or glandular differentiation. The tumors were composed of the following three cell types: gemistocytic (giant) cells, smaller polygonal cells, and spindle cells, with identical immunohistochemical reactions. A panel of monoclonal and polyclonal antibodies was applied. All tumors were found to coexpress keratin and vimentin. A positive reaction for neuron-specific enolase (NSE) was found in three tumors and a positive reaction for chromogranin was found in one tumor. On electron microscopic study, intracytoplasmic whorls of intermediate filaments were seen in the perinuclear area. Dense core "neurosecretory" granules were rarely seen. Intestinal pleomorphic carcinomas are histologically identical to pulmonary giant cell carcinomas. The prognosis is poor due to early tumor spread, with only a few months of postoperative survival. The pleomorphic carcinomas have some of the differentiation characteristics of carcinoid tumors and are best regarded as poorly differentiated variants of neuroendocrine carcinomas.

Adenosquamous carcinoma of the colon--an immunocytochemical and ultrastructural study. Report of two cases and review of the literature.

This paper presents two cases of adenosquamous carcinoma of the colon and brings to 39 the total number documented in medical literature. The concurrent glandular and squamous differentiation of the tumor cells was demonstrated by immunocytochemistry and electron microscopy. Evaluation of the biologic characteristics of all the reported cases suggests that malignant squamous elements in colonic carcinomas behave more aggressively than their glandular counterparts. In contradistinction from the pure squamous-cell carcinoma of the colon, adenosquamous carcinoma does not show the same predilection for the right colon.

Small-cell undifferentiated carcinoma of the rectosigmoid colon.

We describe three patients with small-cell undifferentiated carcinoma of the rectosigmoid colon. Though there was a wide range of patient age, history, and gross presentation of the malignancy, there was overlap in the histopathologic appearance and the biological behavior of the tumor. All three cases had liver involvement at the time of diagnosis. Despite multidrug chemotherapy, two patients died within a year of diagnosis, and the third patient had progressive disease. Ultrastructurally, all cases had membrane-bound dense-core granules, however, there was considerable variation of size and number of granules among the tumors, as well as other forms of endodermal differentiation. Whether small-cell undifferentiated carcinoma presents as a small focus within a neoplastic polyp or as a large primary tumor, the therapy must include a systemic aggressive protocol.

Brown bowel syndrome.

The brown bowel syndrome (BBS) is a rare disease characterized by malabsorption and accumulation of lipofuscin in the smooth muscle cells of the muscularis externa of the small intestine. Recently, we incidentally observed a case of BBS in a colon operated on because of a neoplasm. Our ultrastructural investigation, which demonstrated changes in the mitochondria, further supports the significance of mitochondrial damage in BBS.

Basaloid tumor of the sigmoid colon.

A second case of basaloid carcinoma arising in the midsigmoid colon is reported. By light microscopy the tumor was seen to be composed of islands of small, poorly differentiated cells separated by cellular connective tissue. Also seen were small foci of keratinized cells, Ultrastructure study confirms the largely basal character of the tumor and also shows some cells containing tonofilament bundles, representing a more squamoid differentiation. The similarity of this tumor to basaloid tumors arising in the transitional epithelium of the anal canal is discussed, and the suggestion that the tumor arises from a pluripotential basal cell is made.