Yoke-Sun Lee

Diverticular disease of the large bowel in Singapore. An autopsy survey.

One thousand fourteen consecutive large intestines were removed at autopsy from persons over the age of 14 years and examined for diverticular disease. Diverticulosis was encountered in 194 patients (19 percent). The lesion appeared early in life, after the second decade. Men were affected more frequently than women before the age of 60 years. Chinese men had significantly more diverticular disease than Malayan men (P<0.01) and Indian men (P<0.02). Chinese men also had significantly more diverticular disease than Chinese women. There was a predominance of right colon involvement, with the disease affecting especially the ascending colon and cecum. This pattern was observed in all three major ethnic groups, and in both the Singapore-born and foreign-born Singaporeans. The cause of right-sided diverticulosis is unknown. It appears that, while adoption of the western diet may influence the prevalence of diverticular disease, the site of predilection is determined more by racial or genetic predisposition. All diverticular examined histologically were false, including 39 (20 percent) solitary diverticula. The distribution of solitary diverticula was similar to that of multiple diverticulosis. It is suggested that solitary and multiple diverticulosis are part of the spectrum of the same disease.

p53 expression in pseudoepitheliomatous hyperplasia, keratoacanthoma, and squamous cell carcinoma of skin.

Background. Expression of p53 protein has been described in a variety of human malignant tumors. Recent reports have also demonstrated its presence in benign and reactive lesions. The significance of p53 expression is unclear.

Malignant fibrous histiocytoma at site of metal implant.

The occurrence of malignant tumors at the site of metal implants is rare. The significance of this association is not settled. Its implications, however, are serious. A malignant fibrous histiocytoma arising at the site of an implant done 14 years ago for traumatic fracture of the femur in a 44‐year‐old man is reported. Previous reports are briefly summarized.

Lectin expression in neoplastic and non-neoplastic lesions of the rectum

&NA; The expression of six lectins (Arachis hypogaea, B. simplicifolia I, concanavalin A, Dolichus biflorus, Triticum vulgaris, Lotus tetragonolobus) was studied in 24 adenocarcinomas, 24 adenomas, 20 metaplastic polyps, 17 specimens of mucosal prolapse (solitary ulcer syndrome) and 10 of normal mucosa, all taken from the rectum. Qualitative, quantitative and distributive differences in lectin expression were observed between adenocarcinoma and normal mucosa. These cancer‐associated glycoprotein alterations were also observed, though to a lesser extent, in benign neoplastic and non‐neoplastic lesions of the rectum. It appears therefore that the glycoprotein modifications associated with malignant transformation are not specific indicators of malignancy. It is suggested that the common denominator is a disturbance in the activities of enzymes, particularly the glycosyl‐transferases and glycosidases, involved in the biosynthesis of glycoprotein. This disturbance can occur in situations where cells are less differentiated either through developmental immaturity, rapid cellular division or neoplastic de‐differentiation. These changes are therefore more likely to reflect the state of differentiation rather than the malignant nature of the cells. It is shown that the greater the deviation of the lesion from normal the greater the glycoprotein alterations. The potential usefulness of lectin expressions as predictive indicators of biological behaviour of adenocarcinomas of the large bowel needs further studies.

Autoclaved autograft bone combined with vascularized bone and bone marrow

In this study, the authors investigated enhancing the results of autoclaved autograft bone by combining it with a vascularized bone graft and supplementing it with autogenous bone marrow for replacement of a 2-cm tibial defect in the rabbit model. The study was divided into 4 groups. Group I consisted of autoclaved autograft bone only; Group II, autoclaved autograft bone and vascularized bone graft; Group III, autoclaved autograft bone and autogenous bone marrow; and Group IV, autoclaved bone and autogenous bone marrow and vascularized bone graft. The vascularized bone graft was provided by the ipsilateral fibula, pedicled on the peroneal vessels, and transposed to sit alongside the autoclaved bone. In Group I, all grafts had nonunion at 16 weeks. In Group II, new bone formation was seen at the proximal and distal site of the autoclaved bone, host bone, and vascularized fibular graft junction as early as 2 weeks, and bony union occurred at the 16th week. The autogenous bone marrow-supplemented groups (III and IV) had new bone formation along the entire length of the autoclaved bone. Bony union at the proximal and distal junction was seen as early as 4 weeks, extending to the entire autoclaved bone by the eight week (98% of the cases with 1 case of infection). Histologic examination showed revascularization and capillary ingrowth into the autoclaved bone at 16 weeks, with a significantly improved torsional stiffness when compared with the groups without autogenous bone marrow supplementation. The addition of vascularized bone graft resulted in an improved union rate as compared with the autoclaved bone alone. Autogenous bone marrow supplementation, in addition to the vascularized bone graft, resulted in rapid new bone formation all around the autoclaved bone, early revascularization and incorporation of the autoclaved bone, and a significantly improved torsional stiffness of the reconstruction.

Photosensitive Annular Elastolytic Giant Cell Granuloma with Cutaneous Amyloidosis

Annular erythematous indurated plaques with central clearing developed on sun-exposed areas of a diabetic patient. The lesions were aggravated by sun exposure. Histological examination revealed features as described in annular elastolytic giant cell granuloma. In addition, subepidermal amyloid deposits were identified. Though a coincidental occurrence cannot be excluded, a possible pathogenetic relationship between the two conditions is postulated. It is believed that they are caused by actinic damage to skin altered by diabetes.

Dystrophic and psammomatous calcifications in a desmoid tumor. A light microscopic and ultrastructural study.

A desmoid tumor occurring in the abdominal wall of a 6‐year‐old boy with extensive microcalcifications was documented. Two forms of calcifications were observed: an irregular, amorphous dystrophic calcification of the collagen fibers and an organized, laminated psammomatous calcification (psammoma bodies). Ultrastructural studies revealed that the dystrophic calcification is a result of direct mineralization of individual collagen fibrils with subsequent coalescence to form large, calcified masses. Psammomatous calcification tended to cluster around areas where the collagen fibers assumed a whorled configuration. It is suggested that the circular orientation of the collagen fibers in some way favors the laminar deposition of hydroxyapitite crystals. The cause of the pathologic calcifications is the presence of extensive amorphous eosinophilic degeneration of the collagen fibers.

A fatal congenital myopathy with severe type I fibre atrophy, central nuclei and multicores

An unusual fatal congenital myopathy in a Chinese female infant is described. Muscle biopsy showed type I fibre smallness with central nuclei and focal decrease in oxidative enzyme activities affecting mainly larger type II fibres. Longitudinal sections from glutaldehyde-fixed araldite-embedded material stained with toluidine blue revealed multiple small foci of myofibrillar degeneration (multicores) along the muscle fibres. Electron-microscopic examination confirmed the presence of multicore lesions affecting mainly the larger fibres. In addition, there were definite degenerative changes involving the smaller fibres with central nuclei. The degenerative process started around the pericentronuclear zones with diffuse extension along the whole length of the muscle fibres resulting in severe atrophy. These degenerative changes were similar to those described in pericentronuclear myopathy. It is therefore suggested that the patient might have either had 2 co-existing myopathies viz. multicore disease and pericentronuclear myopathy or a single entity with combinations of features which had not hitherto been described.

Prevalence of Human Papillomavirus Types 16 and 18 in Cervical Carcinomas: A Study by Dot and Southern Blot Hybridization and the Polymerase Chain Reaction

Histologically classified biopsies from 83 women with invasive cervical carcinoma were analyzed by dot blot hybridization for human papillomavirus (HPV) types 16 and 18 infection. Sixty of the 83 (72.3%) were found to contain HPV DNA, of which 43 (51.8%) contained HPV 16 DNA, 12 (14.5%) contained HPV 18 DNA and 5 (6.0%) contained both HPV 16 and 18 DNAs. Southern blot analysis on 65 specimens gave similar results. Of 23 specimens negative by dot blot, 21 were tested by the polymerase chain reaction. Seventeen of the 21 were positive for HPV DNA, of which 13 contained HPV 16 DNA and 4 contained both HPV 16 and 18 DNAs. In all, 95.1% (77/81) were positive for HPV 16 and/or 18 DNA sequences.

Background mucosal changes in colorectal carcinomas

The entire colonic mucosa of 51 cases of colorectal carcinoma was examined histologically. Mucosal lesions including goblet cell hyperplasia, crypt dilatation, ulceration with regeneration, basal cell hyperplasia, metaplastic lesions, and adenomas were encountered. Goblet cell hyperplasia (80.4%) was most prominent adjacent to the carcinoma (transitional mucosa). Whether this represents a precancerous change is controversial. Crypt dilatation (57%) is considered a nonspecific change due to mucosal injury and indicates obstruction to the outlet of the crypts. Ulceration (6%) is often proximal to the carcinoma and is considered secondary to stasis and ischaemia due to obstruction. Basal cell hyperplasia is particularly prominent at the site of lymphoid follicles. It is suggested that the hyperplasia is a reactive response to the presence of stimuli in the intestinal content. It is observed that metaplastic lesions have their origin from these foci of basal cell hyperplasia. The presence of basal cell hyperplasia in metaplastic polyps (14%) indicates that they are active lesions in the process of formation and growth. The occurrence of metaplastic lesions may provide an indication of an adverse environment and a vulnerable mucosa. Adenomas have their origin from basal cells of colonic crypts. They are present in 47% of colorectal carcinoma. The findings support the view that adenomas are the most common and important precursor lesion associated with colorectal carcinoma in man. No de novo foci of malignant transformation was encountered but this does not exclude the possibility of de novo carcinogenesis of the colorectum.The entire colonic mucosa of 51 cases of colorectal carcinoma was examined histologically. Mucosal lesions including goblet cell hyperplasia, crypt dilatation, ulceration with regeneration, basal cell hyperplasia, metaplastic lesions, and adenomas were encountered. Goblet cell hyperplasia (80.4%) was most prominent adjacent to the carcinoma (transitional mucosa). Whether this represents a precancerous change is controversial. Crypt dilatation (57%) is considered a nonspecific change due to mucosal injury and indicates obstruction to the outlet of the crypts. Ulceration (6%) is often proximal to the carcinoma and is considered secondary to stasis and ischaemia due to obstruction. Basal cell hyperplasia is particularly prominent at the site of lymphoid follicles. It is suggested that the hyperplasia is a reactive response to the presence of stimuli in the intestinal content. It is observed that metaplastic lesions have their origin from these foci of basal cell hyperplasia. The presence of basal cell hyperplasia in metaplastic polyps (14%) indicates that they are active lesions in the process of formation and growth. The occurrence of metaplastic lesions may provide an indication of an adverse environment and a vulnerable mucosa. Adenomas have their origin from basal cells of colonic crypts. They are present in 47% of colorectal carcinoma. The findings support the view that adenomas are the most common and important precursor lesion associated with colorectal carcinoma in man. No de novo foci of malignant transformation was encountered but this does not exclude the possibility of de novo carcinogenesis of the colorectum.