K. Y. Lam

Pancreatic endocrine tumour: a 22-year clinico-pathological experience with morphological, immUnohistochemical observation and a review of the literature

The clinico-pathological features of 53 Chinese patients (27 males; 26 females) with pancreatic endocrine tumours were studied. The age range was from 14 to 78 years old (mean: 48 years) with the modal peak in the sixth decade for both sexes. Pancreatic endocrine tumours accounted for 14% of the primary pancreatic tumours operated on in Queen Mary Hospital. The autopsy incidence was 0.11%. Seventy-two per cent (38 cases) of the tumours were clinically functioning, comprising 33 insulinomas, three gastrinomas and two glucagonomas. A rare case of malignant gastrinoma associated with Cushings syndrome was also documented. The functional tumours were seen in the younger patients. The calculated annual incidence of clinically significant tumours was approximately 0.2 per 100,000 population. There was no correlation between the site, functional status and histological patterns of the tumours. Seventy-two per cent of the tumours showed a trabecular pattern. Calcification was present in 5.7% (three cases); two such cases being gastrinomas. Amyloid was found in 25% of tumours, chiefly (92%) in the insulinomas. The main difficulty encountered in diagnosis was distinguishing between solid and cystic tumours of the pancreas. The incidence of malignancy was 15% and the histological features were poor predicative indicators of malignant potential. The metastatic pancreatic endocrine tumours were often detected in the liver and lymph nodes. Immunohistochemical stains showed evidence of multi-hormone production in 18% of cases and all tumours showed a positive reaction to at least one of the six markers, namely, neuron-specific enolase (NSE), chromogrannin (CG), synaptophysin (SYN), insulin (INS), glucagon (GLU) or somatostatin (SOM). The three panendocrine markers (NSE, SYN, CG) were satisfactory for initial screening of the endocrine nature of the tumours if used in combination, as 92% of tumours were positive for at least one of these three markers.

Odontogenic Keratocysts: A Clinicopathological Study in Hong Kong Chinese

Objective To analyze the clinicopathological features of odontogenic keratocysts in Chinese patients.

Pre-operative chemotherapy for squamous cell carcinoma of the oesophagus: Do histological assessment and p53 overexpression predict chemo-responsiveness?

Pre-operative chemotherapy is increasingly used in the treatment of oesophageal carcinoma. However, no features have been identified which can reliably predict a positive response to chemotherapy. The aim of this study was to examine whether histological features and p53 overexpression could predict such response. Prechemotherapy endoscopic biopsies from 55 patients, who subsequently completed two courses of chemotherapy followed by surgical resection, were studied. Patients were classified into responders and non-responders according to clinical and pathological findings. Pathological features of the endoscopic biopsies examined included adequacy of the tumour tissue, histological grade, degree of keratinisation, histologic patterns, mitotic rates and nuclear pleomorphism. Biopsy specimens were also tested for p53 overexpression using p53 protein specific mouse monoclonal antibody DO-7 on paraffin sections. Histologic features and p53 expression were correlated to chemoresponsiveness. 76% (42 of 55) of patients had sufficient biopsy tissue for assessment. Response to chemotherapy was evident in 64% (n = 27) of patients. None of the non-responders had tumours with high-grade nuclear pleomorphism compared with 37% (10 of 27) of responders (P = 0.01). All patients with high-grade nuclear pleomorphism responded to chemotherapy. No significant differences were found between the responders and non-responders with respect to tumour differentiation (P = 0.7), degree of keratinisation (P = 0.3) and mitotic rates (P = 0.8). Overall, p53 overexpression was noted in 67% (28 of 42) of patients. This was more prevalent in non-responders (12/15) compared to responders (16/27), but this was not statistically significant (P = 0.08). The degree of p53 overexpression had no significant relationship with responsiveness to chemotherapy. High-grade nuclear pleomorphism, identified on pretreatment biopsy specimens, correlated with response to chemotherapy, whereas p53 overexpression did not correlate with response. Improved tissue sampling and further investigations should be done so that the assessment of prechemotherapeutic endoscopic biopsies can have significant impact on clinical decision making.

C-erbB-2 protein expression in oesophageal squamous epithelium from oesophageal squamous cell carcinomas, with special reference to histological grade of carcinoma and pre-invasive lesions.

AIMSnC-erbB-2, an oncogene, is member of the growth factor receptor family. Its role in activation of oesophageal squamous cell carcinoma is poorly understood. The aim of this study was to evaluate the part played by c-erbB-2 in oesophageal squamous cell carcinoma in Hong Kong Chinese patients.nnnMETHODSnWe examined the expression of the c-erbB-2 oncoprotein in 104 oesophageal squamous cell carcinomas from 89 men and 15 women, ranging in age from 41 to 89 years (mean 63). C-ercB-2 expression was studied with monoclonal antibody, using an antigen retrieval method.nnnRESULTSnFocal c-erbB-2 membrane staining was present in 10 (10%) of 104 squamous cell carcinomas. Staining was also noted in the adjacent dysplastic epithelium (n=2) and non-tumour inflamed epithelium (n=2). In carcinomas, the c-erbB-2 membrane staining was identified only in superficial well-differentiated tumour cells and the expression did not predict biological behaviour.nnnCONCLUSIONSnWe conclude that the c-erbB-2 oncoprotein is expressed in a portion of oesophageal squamous cell carcinomas and precursor lesions. This suggests that c-erbB-2 activation plays a certain role, mostly probably during the early stages, in carcinogenesis in oesophageal squamous cell carcinomas from Hong Kong Chinese patients.

Desmoplastic variant of ameloblastoma in Chinese patients

Desmoplastic ameloblastoma is a rare tumour, and we know of only 43 previously reported cases. We report seven Chinese patients (five men and two women) with the desmoplastic variant of ameloblastoma, which makes up 9% of all ameloblastomas diagnosed during the years 1981-1995. The age ranged from 18 to 68 years (mean 43). Five of the tumours were in the maxilla and two were in the mandible. Five of them were situated anteriorly, the remaining two cases involving both anterior and posterior maxilla. The features of the 42 cases previously reported were reviewed and were compared with those in the present study. Our results differ in that we found a male predominance, wider age range and more tumours in the maxilla. Histologically, this variant of ameloblastoma is characterized by abundant collagenous stroma. Because the epithelial clusters may show prominent squamous metaplasia or may be compressed into thin strands in most areas, the appearance may mimic a squamous odontogenic tumour or odontogenic fibroma. The behaviour of this variant of ameloblastoma is likely to be the same as that of the classic ameloblastoma.

Tracheostomal stenosis after total laryngectomy: an analysis of predisposing clinical factors.

Stenosis of the terminal tracheostome is a distressing complication of total laryngectomy. A retrospective analysis of 207 patients who underwent total laryngectomy is presented; an overall incidence of tracheostomal stenosis of 13% is reported. The incidence of tracheostomal stenosis is higher in females (26%), patients having immediate tracheoesophageal puncture (19%), pectoralis major myocutaneous flap pharyngeal reconstruction (26%), and tracheostomal infection (50%) which is shown to be significant (P<.05). However, on multivariate analysis, only female sex and tracheostomal infection are independent determinants. Recognition of these clinical factors identifies patients at increased risk of developing this complication and thus allows appropriate perioperative planning to minimize its incidence.

Use of the pectoralis major muscle flap for repair of a tracheoesophageal fistula

A case of tracheal rupture after a Lewis-Tanner esophagectomy in a patient with carcinoma of the esophagus was complicated by the formation of a tracheoesophageal fistula after initial direct repair. The fistula was successfully treated with a pectoralis major muscle flap moved into the superior mediastinum by a sternotomy and excision of the upper part of the sternum and adjacent costal cartilages.

Expression of p53 in oesophageal squamous cell carcinoma in Hong Kong Chinese

We studied p53 overexpression in a series of 99 primary oesophageal squamous cell carcinomas (28 well-differentiated, 42 moderately-differentiated and 29 poorly-differentiated squamous cell carcinomas) from Chinese patients using the p53 protein specific mouse monoclonal antibody DO-7 on paraffin sections. The p53 protein was detected in 30% (30 cases) of the tumours. A significantly higher positive rate was noted in the poorly-differentiated tumours (11% for the well-differentiated, 31% for the moderately-differentiated and 48% for the poorly-differentiated tumours). In addition, strong positive p53 staining was identified only in the less differentiated tumour cells in the periphery of the tumour cell nests in all the cases and the expression was weaker in the better differentiated foci. The central keratinizing areas and the immediately adjacent tumour cells were always negative for p53. The adjacent normal oesophageal mucosa was all negative for p53 protein but the non-invasive dysplastic epithelium next to the tumours could also be strongly positive for p53 protein (four out of 14 cases in which the dysplastic epithelium adjacent to the tumour was adequately sampled). In two out of these four cases, the dysplastic epithelium showed staining for p53; even the adjacent invasive tumour was negative for p53. It is concluded that there is a strong relationship between p53 overexpression and tumour cell differentiation in oesophageal squamous carcinoma and overexpression of p53 can occur in non-invasive tumour cells.

Cardiac tumors in Hong Kong a clinicopathological study of 66 cases

A retrospective analysis of cardiac tumors surgically excised in a 14-year period in Hong Kong was performed. The study showed 65 primary tumors (64 cardiac myxomas, one unclassified sarcoma), and one metastatic leiomyosarcoma. All patients were Chinese except a Filipino woman who had a cardiac sarcoma. The incidence of primary cardiac tumors in Hong Kong Chinese was estimated to be 0.83 per million population per year. The mean age of patients at operation was 50. There were 37 females and 27 males with no difference in mean ages between the two groups. The average size of myxoma was 4.7 cm. The anatomic locations of the 64 myxomas were left atrium (60), right atrium (2), mitral valve (1), and atrial septum on both sides (1). The main presenting clinical features were dyspnea (46%), cerebral embolism (32%), and palpitation (27%). No familial or syndromatic case was noted. Well-differentiated glandular structures were found in one right atrial myxoma. The findings were compared with those of a local series of cardiac tumors found at autopsy.

Clinico-pathological correlation of glucagon-positive pancreatic endocrine tumours: a presentation of five cases

The clinicopathologic correlation of five cases of glucagon-positive pancreatic tumours is reviewed. Two cases with the typical glucagonoma syndrome but with atypical manifestations in the central nervous system are presented. These neurological manifestations might constitute a new paraneoplastic syndrome. The last three cases illustrate how glucagon positivity can be present in pancreatic endocrine tumours other than in the classical glucagonoma.