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K Y Lam

Publications and source records attributed to K Y Lam.

At least 73 records · Page 4Linked to original sources
PubMed2000

Parathyroid adenomas with pronounced lymphocytic infiltration: no evidence of autoimmune pathogenesis.

Pronounced lymphocytic infiltration in parathyroid adenoma is rare, with only six previously reported cases in the literature. The aims of this study are to review the features and investigate the pathogenesis of this rare entity. Two solitary parathyroid adenomas having this feature were reported, and the clinicopathologic features of all the documented cases were reviewed. The nature of the lymphoid infiltrate and the presence of Epstein-Barr virus (EBV) were analyzed to unveil the pathogenesis of this infiltrate. One adenoma was found in a 70-yr-old woman with primary hyperparathyroidism and valvular heart disease. The other was an autopsy finding in a 48-yr-old man who had presented with hypercalcemic crisis. The lymphoid cell population within the tumors was composed of B cells and different subsets of T cells. EBV was not detected in the infiltrates. The lymphocytic infiltrate in parathyroid adenoma is an unusual histologic entity. Its presence is unlikely to imply an autoimmune disorder. We hypothesize that the lesion may be a result of local tissue response to parathyroid adenoma.

Journal Article↗
PubMed2000

Esophageal small cell carcinomas: clinicopathologic parameters, p53 overexpression, proliferation marker, and their impact on pathogenesis.

OBJECTIVE: To evaluate the clinicopathologic features and the roles of p53 and MIB-1 in esophageal small cell carcinoma. METHOD: Twenty patients (14 men and 6 women) with esophageal small cell carcinoma treated in our hospital from 1982 through 1996 were studied. The clinicopathologic features, treatment received, and survival data of these patients were documented. Representative tissue was collected from each tumor, and immunohistochemical preparations for p53 protein and MIB-1 were made. RESULTS: Small cell carcinoma accounted for 1.3% of all esophageal malignant tumors. The median age of patients at presentation was 60 years. On gross examination, the tumors were large ulcerative lesions (median length, 7.5 cm). In 17 patients in whom p53 immunohistochemical study was performed, p53 protein was detected in 65% (9 of 17). All stage IV tumors were negative for p53 expression. The median tumor cell MIB-1 score was high at 855 (range, 810-964) positive cells per 1000. Overall median survival was 3.4 months. In patients who underwent chemotherapy, there was significant response. CONCLUSIONS: Esophageal small cell carcinoma is an aggressive tumor. Overexpression of p53 is associated with early stages of carcinogenesis. The high proliferative index, as defined by the MIB-1 immunohistochemical method, may be related to aggressive behavior and high sensitivity to chemotherapy and radiotherapy.

Adult↗
PubMed2000

Metastatic tumors to the spleen: a 25-year clinicopathologic study.

OBJECTIVE: The clinicopathologic features of splenic metastases have seldom been investigated. The aim of this study was to evaluate the clinical and pathological impact of splenic metastases. CASE MATERIAL: We reviewed the clinical/autopsy records and pathologic features of 92 Chinese patients (58 men, 34 women) with secondary nonlymphoid splenic tumors recorded during a 25-year period. RESULTS: The incidence of splenic secondary tumors at autopsy was 0. 6% and at splenectomy, 1.1%. The lesions were often seen in elderly patients (mean age, 60 years). Seven (8%) of the splenic lesions were symptomatic. The symptomatic splenic lesions, as compared with asymptomatic lesions, were bigger and were found more often in women and younger patients. Two patients experienced spontaneous splenic rupture because of metastatic carcinoma. Eighty-seven (95%) of the secondary splenic tumors were carcinomas. Lung was the most common primary tumor site (21%), followed by the stomach (16%), pancreas (12%), liver (9%), and colon (9%). Rarely reported sources of primary tumor, such as esophageal carcinomas, nasopharyngeal carcinoma, and choriocarcinoma, were also found. Splenic metastases could be identified macroscopically in 74 (80%) of our patients. Grossly, splenic metastases involved the splenic capsule (n = 8) or were solitary (n = 31), multiple (n = 30), or diffuse (n = 8) lesions in the splenic parenchyma. Isolated splenic metastases were noted in 5.3% of the metastases found at autopsy. Many of the metastatic lesions in the spleen were identified shortly after primary tumors were detected (mean latent period, 6.7 months). The time from diagnosis of the primary tumor to metastasis to the spleen was more than 2 years in 14 patients. CONCLUSIONS: Splenic metastases are uncommon. A variety of clinical and pathologic patterns were noted in our series.

Age Factors↗
PubMed1999

Parathyroid autotransplantation during thyroidectomy: is frozen section necessary?

OBJECTIVE: To evaluate the accuracy of parathyroid gland identification and the need for routine frozen section examination before parathyroid autotransplantation during thyroidectomy. DESIGN: A prospective case series. SETTING: An endocrine surgical unit. PATIENTS: From January 1, 1995, to December 31, 1997, parathyroid autotransplantation was attempted for devascularized or inadvertently removed glands in 152 (33.7%) of 450 patients during thyroidectomy. Before autotransplantation, a biopsy specimen of the transplanted tissue was sent for histological examination without frozen section confirmation. MAIN OUTCOME MEASURES: Positive identification of parathyroid tissue in microscopic examination. RESULTS: Of 179 attempted autotransplantations of parathyroid glands, parathyroid tissue was confirmed in 167 biopsy specimens (93.3%). Incorrect identification of parathyroid gland occurred in 12 instances. The tissue mistaken as parathyroid gland included fat in 6 cases, thyroid tissue in 4 cases, lymph node in 1 case, and thymus in 1 case. Transplantation of at least 1 parathyroid gland (range, 1-3) was confirmed in 144 patients. For patients with confirmed parathyroid autotransplantation at risk of hypoparathyroidism (n = 112), postoperative transient hypocalcemia occurred in 22 (19.6%), while no patient developed any permanent hypocalcemia during a median follow-up of 6 months. CONCLUSIONS: Devascularized or inadvertently removed parathyroid glands can be identified expeditiously without routine frozen section during thyroid surgery. Immediate autotransplantation should be performed and permanent hypoparathyroidism can be avoided with this measure.

Adolescent↗
PubMed1999

Pancreatic solid-cystic-papillary tumor: clinicopathologic features in eight patients from Hong Kong and review of the literature.

Solid-cystic-papillary tumors (SCPTs) of the pancreas are rare. The clinicopathologic features and pathogenesis of these tumors have attracted a number of investigations, but the results remain unclear. We investigated the clinicopathologic data, immunohistochemical expression of the pan-endocrine markers, hormones, steroid receptors, and p53 overexpression in pancreatic SCPTs from eight Chinese patients (seven women, one man) collected over a 24-year period. They accounted for 2.5% of the primary pancreatic tumors. The tumors were seen in young women (mean age 27 years). They were large (mean size of resected tumor was 8.4 cm), benign, had solid and cystic areas, and were evenly distributed in the pancreas. The main differential diagnosis was pancreatic endocrine tumor. The tumors were negative for pan-endocrine markers, hormones, estrogen receptor, progesterone receptor, and p53. To date, 452 pancreatic SCPTs have been documented in the English literature. They occurred in patients of different ethnic groups, particularly in non-Caucasians. The tumors were frequently noted in young females. Uncommon cases of malignant pancreatic SCPTs were often found in older men and had indolent behavior. It was concluded that pancreatic SCPTs have distinct clinicopathologic characteristics. The present observations, together with a review of the literature suggests that overexpression of p53 or estrogen receptor is not important in the pathogenesis of pancreatic SCPTs.

Adolescent↗
PubMed1999

Clinicopathological analysis of elective neck dissection for N0 neck of early oral tongue carcinoma.

BACKGROUND: The study aims at evaluation of the efficacy of elective neck dissection as a staging and therapeutic procedure for N0 neck of early carcinoma of the oral tongue by whole organ serial sectioning. METHODS: There were 50 stage I and II patients. The neck dissection specimens were whole organ sectioned in 3-mm intervals for the evaluation of nodal metastasis. RESULTS: There were 18 (36%) patients with subclinical nodal metastasis. The total number of metastatic nodes were 31 (1%) among all 2,826 nodes being examined. The metastatic foci had a median size of 3 mm and occupied a median of 6% of the cross sectional area of the involved nodes. The ipsilateral level II nodes were the commonest (26%) site of metastasis. Metastatic nodes were present in 34% patients who had negative preoperative radiological assessment and in 20% patients who had negative intraoperative frozen section sampling of neck nodes. Patients with subclinical nodal metastasis had a high incidence of regional recurrence (62%) and low survival (27%) when postoperative radiotherapy was not given after elective neck dissection. CONCLUSIONS: Ipsilateral level I,II,III neck dissection is an adequate diagnostic procedure for staging of the N0 neck of early oral tongue carcinoma. Its diagnostic role cannot be replaced by the available pre-operative radiological screening and intra-operative frozen section sampling. However, elective selective neck dissection is an effective but not adequate therapeutic procedure, and post-operative adjuvant radiotherapy and chemotherapy have to be considered for all pathologically positive necks.

Adolescent↗
PubMed1999

Anaplastic carcinoma of the thyroid.

BACKGROUND: Anaplastic thyroid carcinoma, albeit rare, is one of the most aggressive human tumors, with a dismal prognosis. METHODS: Twenty-eight patients with anaplastic thyroid carcinoma were identified during the past 30 years to evaluate its clinicopathologic features and to document our experience in management. Potential risk factors for survival time were analyzed. RESULTS: The usual presentation was that of a rapidly enlarging neck mass. Distant metastases were present in 50% of patients on presentation. Palliative resection was performed in 16 patients. The median survival was 38 days, and the 2-year survival rate was 4%. Among factors analyzed, patients selected for surgical resection, absence of distant metastases at presentation, young age, and tumor size <6 cm were associated with an increased survival time. Concomitant well-differentiated thyroid carcinoma and p53 overexpression were present in 12 of the 22 and 13 of the 19 specimens, respectively. CONCLUSIONS: Patients with anaplastic carcinoma of thyroid have a dismal prognosis heralding imminent death. Surgical ablation followed by adjuvant therapy can provide palliation for selected patients only.

Aged↗
PubMed1999

Expression of p21/waf1 in oral squamous cell carcinomas--correlation with p53 and mdm2 and cellular proliferation index.

The cyclin-dependent kinase inhibitor p21/waf1 is regulated by p53-dependent and p53-independent pathways. In addition, mdm2 is an oncogene which forms an auto-regulatory loop with the normal p53 protein and its role has been implicated in oncogenesis. To determine whether a correlation exists between the expression of these gene products, tumor differentiation, tumor staging and radiation therapy, we investigated the expression of p21, p53 and mdm2, and cellular proliferation by Ki-67 (MIB1) labeling index using immunohistochemistry in 88 human oral squamous cell carcinoma (SCC) samples from 56 patients. Tumor expression of all nuclear proteins was scored according to the percentage of positive cancer nuclei, both with the cancer tissue as a whole as well as in different epithelial compartments of differentiation. Positive p21, p53, mdm2 and MIB1 staining was present in 82.4, 67.8, 25.9 and 98.8% of the SCC samples. The staining in different epithelial compartments of differentiation varied: those of p21 and mdm2 present predominantly in suprabasal and upper regions of the tumors: those of p53 and MIB1 in basal and suprabasal regions. Higher levels of p21 expression were seen in actively proliferating tumors (P = 0.025). p21 expression positively correlated with mdm2 expression but not with p53 expression. Moreover, the level of p21 expression was higher in older patients (P = 0.024) and female patients (P = 0.008). There was no significant association among p53, mdm2 and MIB1. Expression of p53 was higher in tumors with poorer cellular differentiation and in younger patients (P = 0.038 and 0.028). There was no association between tumor stage by TNM classification and the expression of any of these gene products or proliferation index. Radiation therapy did not alter the expression of any of these. To conclude, p21 protein was overexpressed in oral SCCs, and this overexpression was related to cell proliferation index and mdm2 expression but independent of p53 protein alteration. Overexpression of p21 alone appeared to be insufficient to suppress tumor progression.

Adult↗
PubMed1999

Surgical implications of underestimation of adrenal tumour size by computed tomography.

BACKGROUND: Size of adrenal mass is an important consideration during adrenal surgery, with regard to the choice of surgical approach and management of adrenaloma. The aim of the present study was to evaluate the precision of preoperative computed tomography (CT) on the size estimation of adrenal lesions and to review its potential implications on surgical decision making. METHODS: Records of 110 patients who underwent adrenalectomy for various adrenal pathologies from 1981 to 1997 were reviewed retrospectively. Patients (n = 92) who had documented dimensions of adrenal mass by both preoperative CT and pathological examination were selected for analysis. RESULTS: CT overall underestimated the actual size of adrenal lesions by 16 per cent compared with measurement of resected specimens (mean 3.1 versus 3.6 cm; P < 0.001). There was a significant underestimation of the actual size of adrenal lesions measuring less than 6 cm by CT but not for lesions larger than 6.0 cm. Phaeochromocytoma (n = 17) was the only pathological condition consistently underestimated by CT. CONCLUSION: Conventional CT overall underestimates the real size of adrenal lesions, in particular phaeochromocytoma and adrenal tumours of less than 6.0 cm in size. Surgical decision making based on size should take this limitation into account.

Adrenal Gland Neoplasms↗
PubMed1999

Splenic vascular lesions: unusual features and a review of the literature.

Hamartoma and peliosis are uncommon splenic lesions. Approximately 120 splenic hamartomas and 40 splenic peliosis have been reported in the English literature. In the present study, a unique case of multiple splenic hamartomas with peliosis was reported. The splenic lesions were incidental findings in a 36-year-old man with ruptured sarcomatoid renal cell carcinoma. They were diagnosed clinically as metastatic renal cell carcinoma. On pathological examination, peliosis was noted in the splenic hamartomas as well as in the splenic parenchyma. In addition, the clinicopathological features of five other splenic hamartomas (including one giant hamartoma) noted in our department were presented. A re-evaluation of the features of the splenic hamartomas documented in the English literature was also done.

Adult↗
PubMed1999

Malignant melanoma of the oesophagus: clinicopathological features, lack of p53 expression and steroid receptors and a review of the literature.

AIMS: Fortunately, primary malignant melanoma of the oesophagus is a rare entity. The aims of this study were to evaluate the clinicopathological features, p53 over-expression and steroid receptors in oesophageal melanomas and to review the reported cases in the literature. METHODS: Melanomas reported during a 15-year period (1982-1996) in the Queen Mary Hospital were studied. The clinicopathological features and survival data of patients with oesophageal melanomas were noted. Representative tissue was collected from each tumour and immunohistochemical preparations for HMB-45, p53, oestrogen and progesterone receptors were made. A review of oesophageal melanomas reported in the literature was also performed. RESULTS: Three cases of primary malignant melanoma of the oesophagus were found. They accounted for 3% of melanomas and 0.2% of oesophageal cancers diagnosed. The melanomas were fusiform and large at the time of resection. All three patients died of their malignancy within 9 months of operation. The tumours stained positive for HMB-45 and were negative for p53, oestrogen and progesterone receptors. From previous reports, 154 oesophageal melanomas were documented. The tumours were fusiform, large, often pigmented and located in either the middle or lower oesophagus. Although many oesophageal melanomas presented at early stages (stages I or II), their biological behaviour was aggressive. The 5-year survival rate was 5.7%. CONCLUSIONS: Melanoma of the oesophagus is an aggressive tumour. There is no evidence for the p53 gene and female sex hormones having a role in the development or progression of the tumour.

Aged↗
PubMed1999

Teratoma in the region of adrenal gland: a unique entity masquerading as lipomatous adrenal tumor.

BACKGROUND: The aim of this study was to establish the clinical and pathologic aspects of 3 atypical lipomatous lesions in the region of the adrenal gland. METHODS: Three young Chinese patients (ages 18, 18, and 37 years) were seen for nonspecific back pain. Radiologic examination revealed a lipomatous lesion in the region of the adrenal gland, and hormonal assessment was normal. Calcification was noted in 2 of the 3 lesions. Adrenalectomy was performed because of the size (diameter 7.5, 10, 11 cm) of the tumors with suspected local symptoms. RESULTS: On gross examination 2 tumors were cystic and 1 was solid. In all 3 patients the diagnosis was mature teratomas. The tumors were composed of mature tissues arising from more than 1 germinal layer. There was no evidence of immature elements or malignancy. Adipose tissue was the predominant component in the tumors. There was no evidence of recurrent diseases in all these patients during follow-up. CONCLUSIONS: To our knowledge, this is the first report of teratomas occurring in the adrenal region. Teratoma should clinically and radiologically be included in the differential diagnoses of lipomatous adrenal lesions. Excision of the teratoma is advocated.

Adolescent↗
PubMed1999

Telomerase activity in thyroid malignancy.

Telomerase activity seems to play a role in the development and pathogenesis of thyroid carcinoma. Its incidence of expression and its application as a tumor marker remain to be elucidated. Thyroid tissues obtained during thyroidectomy from 1996-1998 were rapidly frozen and stored at -80 degrees C until processed. Telomerase activity was determined using telomeric repeat amplification protocol (TRAP). Histology of the tissue examined (67 benign and 59 malignant) was reviewed. Telomerase activity was detected in 15 of 52 papillary carcinomas (29%); 1 of 1 thyroid lymphoma (100%); 1 of 2 anaplastic carcinomas (50%); and 2 of 16 lymphocytic thyroiditis specimens (13%). Telomerase activity was not detectable in 35 normal thyroid, 9 follicular adenoma, 7 nodular hyperplasia, 2 follicular carcinoma, and 2 medullary carcinoma. Lymphocytic thyroiditis was detected in 8 of 37 (22%) apparently normal thyroid tissues adjacent to papillary thyroid carcinoma and telomerase activity was present in 2 of these 8 specimens (25%). In conclusion, telomerase does not appear to be frequently activated in papillary thyroid carcinoma. The association of lymphocytic thyroiditis with papillary thyroid carcinoma may limit its clinical usefulness as a tumor marker.

Adolescent↗
PubMed1999

Malignant lymphoma of the thyroid. A 30-year clinicopathologic experience and an evaluation of the presence of Epstein-Barr virus.

Lymphoma of thyroid is uncommon, and Epstein-Barr virus (EBV) is found in many lymphomas. We studied the clinicopathologic characteristics in Hong Kong Chinese and analyzed the presence of EBV in thyroid lymphomas by reviewing data collected during 3 decades. We studied EBV gene expression by in situ hybridization and immunohistochemistry. Primary thyroid lymphomas were found in 23 patients (diffuse large B-cell lymphoma, 18; marginal zone B-cell lymphoma, 4; plasmacytoma, 1), and secondary lymphomas were found in 9 patients (diffuse large B-cell lymphoma, 3; Burkitt lymphomas, 2; Burkitt-like lymphoma, 1; hairy cell leukemia, 1; nasal T-cell and natural killer cell lymphoma, 1; and intestinal T-cell lymphoma, 1). Primary thyroid lymphomas were large (mean, 7 cm), found commonly in older women, and often misdiagnosed as undifferentiated carcinomas. Fine-needle aspiration was not helpful for diagnosis. Fifteen patients had Hashimoto thyroiditis. A history of thyrotoxicosis was found in 3 patients, and coexistence of 3 diseases (papillary microcarcinomas, primary thyroid lymphoma, and Hashimoto thyroiditis) was found 4 patients. The 5-year survival rate for primary thyroid lymphoma was 53%. Combined surgery and radiotherapy seemed to be the best treatment. Secondary thyroid lymphomas often were asymptomatic. EBV messenger RNAs were detected in 1 primary and 1 secondary thyroid lymphoma. The EBV gene expression in primary thyroid lymphoma showed a type II latency pattern. Thyroid lymphomas in Chinese had important clinicopathologic features. EBV may have a role in a subset of cases.

Aged↗
PubMed1999

Collision of endometrioid carcinoma and stromal sarcoma of the uterus: a report of two cases.

Two uterine collision tumors are reported, one in an 85-year-old woman and the other in a 47-year-old woman. Each tumor was composed of a smaller grade 1 endometrioid adenocarcinoma that was distinct from a larger component of high-grade stromal sarcoma. The separate components in these tumors could be detected on gross, microscopic, and immunohistochemical studies. The clinicopathologic features and indolent behavior of these tumors suggest that they should be distinguished from malignant mullerian mixed tumors.

Aged↗