Giant adrenal lipoma: a report of two cases and review of literature

Lipoma of the adrenal gland is extremely rare. We report two cases of adrenal lipomas, one in a 64-year-old female and the other a 78-year-old male. The sizes of these tumours (4.5 cm and 8 cm) were larger than those reported in the literature. Both cases were found incidentally, one at autopsy and the other during ultrasonographic examination for unrelated condition. The histogenesis, clinicopathological features, differential diagnosis and management of these cases are discussed.

Lymphoma of the breast in Hong Kong Chinese

Fourteen cases of non-Hodgkin's lymphoma presenting as breast mass from 1974 to 1996 were reviewed. The median age of presentation was 51 years. Three patients had bilateral disease and five had disseminated disease. A predominance of B cell disease of diffuse large cell histology was noted. Painless lumps were the most common presenting features and most patients were treated with excisional biopsy followed by combination chemotherapy. Radiotherapy was added to local bulky disease. Six patients, however, underwent mastectomy. The overall CR rate was 74 per cent, lasting a median of 32 months. At a median follow-up of 60 months five patients were still alive, one with relapsed disease. Salvage treatments for relapsed patients were uniformly poor. Compared to reported western series, our patients had more high grade disease, more T cell disease and more CNS relapses. Improvements in treatment may involve the use of fine needle aspiration of breast lesion prior to surgery, primary CNS prophylaxis in high grade disseminated disease and high dose chemotherapy with marrow/stem cell rescue in relapsed cases.

Recognition of unique carboxyl-terminal motifs by distinct PDZ domains

The oriented peptide library technique was used to investigate the peptide-binding specificities of nine PDZ domains. Each PDZ domain selected peptides with hydrophobic residues at the carboxyl terminus. Individual PDZ domains selected unique optimal motifs defined primarily by the carboxyl terminal three to seven residues of the peptides. One family of PDZ domains, including those of the Discs Large protein, selected peptides with the consensus motif Glu-(Ser/Thr)-Xxx-(Val/Ile) (where Xxx represents any amino acid) at the carboxyl terminus. In contrast, another family of PDZ domains, including those of LIN-2, p55, and Tiam-1, selected peptides with hydrophobic or aromatic side chains at the carboxyl terminal three residues. On the basis of crystal structures of the PSD-95-3 PDZ domain, the specificities observed with the peptide library can be rationalized.

Primary cardiac lymphoma

Primary cardiac lymphoma is a rare entity. We report on the clinicopathological features of 2 patients with primary cardiac lymphomas: one involving the right atrium resulting in intractable right heart failure, and the other involving the pericardium with massive pericardial effusion. In the first patient, sternotomy and surgical biopsy of the tumor were performed to arrive at the diagnosis. In the second patient, CT thorax and transesophageal echocardiography helped to diagnose the pericardial tumor, and cytological examination of the pericardial fluid established the pathological diagnosis of lymphoma. Combination chemotherapy (COPP) was started in both patients. The first patient died on the first day of chemotherapy due to intractable heart failure, while the second attained a partial response to chemotherapy but died of progressive disease 8 weeks later. This is followed by a literature review of 21 patients with primary cardiac lymphoma. In conclusion, the prognosis of primary cardiac tumor remains poor.

Pathogenesis of gastric lymphoma: the enigma in Hong Kong

BACKGROUND

Helicobacter pylori (H. pylori) infection has been postulated to be a pathogenetic factor in gastric lymphoma. However, the etiological factors for gastric lymphoma could vary in different populations.

MATERIALS AND METHODS

We looked for histological evidence of H. pylori infection in 53 gastrectomy specimens from Hong Kong Chinese patients with primary gastric B-lymphoma. We also screened for Epstein-Barr virus (EBV) in these cases using in situ hybridization with oligonucleotide probes for EBV-encoded small RNA1 and 2.

RESULTS

H. pylori was found in 29 of 53 (55%), including 8 of 13 (62%) cases of low-grade lymphoma of mucosa-associated lymphoid tissue (MALT) type. These infection rates in gastric lymphoma are lower than those reported in Western populations (80%-100%) and comparable to that found in healthy Chinese blood donors (55%) or in non-ulcer dyspeptic patients (52%-57%). EBV was found in tumor cells only in one case of high-grade gastric lymphoma with low-grade MALT component which was H. pylori-negative, and in occasional nontumor-lymphoid cells in 7 other cases.

CONCLUSIONS

These results suggest that (1) the role of H. pylori in pathogenesis of gastric lymphoma may vary in different populations; (2) very few gastric lymphomas are associated with EBV; (3) not all low-grade gastric MALT lymphomas are H. pylori-dependent.

Lymphoepithelioma-like carcinoma of the skin

The histopathological findings of two cases of primary lymphoepithelioma-like carcinoma (LELC) of the skin occurring in two elderly Chinese individuals are presented. Microscopically, they were well circumscribed and were composed of irregular nests of malignant epithelial cells in a background of reactive lymphoid cells including mature plasma cells. A focus of epithelial dysplasia was noted in the adjacent epidermis in one case, suggesting that the LELC might have originated from the overlying epidermis. The epithelial nature of the tumors was confirmed by cytokeratin staining. In situ hybridization for Epstein-Barr virus-encoded RNA (EBER) showed that the tumor cells were uniformly negative, although positive signals were detected in scattered background lymphocytes in case 1. Our results confirm the previous observation that LELC of skin is not related to Epstein-Barr virus, even in Chinese subjects. Nevertheless, such negative findings may prove to be of diagnostic value in excluding the alternative more common diagnosis of metastatic nasopharyngeal carcinoma, which is uniformly positive for EBER.

Primary B cell lymphoma of the mediastinum

Primary B cell mediastinal lymphoma has been recognized as a distinct entity recently. This is a retrospective study to define the clinical features and treatment outcome over a 10-year period. Twenty-four consecutive patients (male/female: 11/13) with B cell lymphoma primarily involving the mediastinum were studied. The median age was 34 years. Symptoms were mainly referrable to the chest, with superior vena cava syndrome (SVCO) present in one-third of the patients. Bulky disease was present in over half (58 per cent) and B symptoms were present in 38 per cent of patients. The overall CR rate was 70 per cent and the 5-year OS rates were 56 per cent and 72 per cent for all and CR patients respectively. Five (71 per cent) primary refractory patients and four (66 per cent) relapsed patients died despite salvage therapy. Six relapses occurred at a median of 6 months from treatment. This study showed that primary large B cell lymphoma of the mediastinum is a clinically distinct entity affecting young patients. A significant proportion attained CR and overall, more than half achieved prolonged remission, and most of the relapses occurred early. However, those who failed to attain CR or relapsed still had a poor outcome. An intensive therapy such as autologous bone marrow transplant has to be considered in this subgroup of patients.

Mesh hernioplasty using a stapler

BACKGROUND

The recent development of laparoscopic hernioplasty has evoked extensive re-examination of the safety and effectiveness of using synthetic mesh materials in hernia surgery. We have investigated the efficacy of anterior stapling mesh repair in the treatment of inguinal hernia.

METHODS

From July 1993 to June 1994, a modified open mesh hernioplasty using staples for anchorage has been performed in 127 patients.

RESULTS

The mean age of patients was 61.4 +/- 13.0 years. Over 90% of them were operated on under local anaesthesia. The operation time ranged from 30 to 95 min with a median of 39 min. Only sixteen patients (12.6%) required postoperative parenteral analgesics and the median time for resuming daily activities was 7 days. Apart from two patients with reactionary haemorrhage, there was no other significant complication observed. Only one recurrence was encountered over the 26-month median follow-up period.

CONCLUSIONS

We conclude that the modified mesh hernia repair with a stapling device is a feasible, inexpensive and safe procedure that is well tolerated under local anaesthesia by most patients.

Vitamin E potentiates arachidonate release and phospholipase A2 activity in rat heart myoblastic cells

Cytosolic phospholipase A2 (cPLA2) selectively catalyses the release of arachidonic acid from the sn-2 position of glycero-phospholipids to produce prostaglandins and leukotrienes. In this study, vitamin E enrichment of rat heart myoblastic H9c2 cells caused an increase in the release of arachidonate during ionophore (A23187) stimulation. PLA2 activity in the cytosolic fraction was also enhanced but enzyme activity in the particulate fraction was not affected by this treatment. Immunoblotting analysis with a polyclonal anti-cPLA2 antibody showed an increased level of the enzyme in vitamin E-treated cells. Direct incorporation of vitamin E into lipid vesicles in the assay mixture resulted in modulation of enzyme activity in a biphasic manner. Pretreatment of cells with phorbol 12-myristate 13-acetate, a known activator of protein kinase C, synergistically potentiated the ionophore-induced arachidonate release in both the control and vitamin E-treated cells. However, vitamin E treatment by itself did not affect the protein kinase C activity, indicating that the vitamin E-induced activation of cPLA2 was independent of the protein kinase C cascade. Collectively, these results suggest that vitamin E potentiates arachidonate release through the direct and/or indirect modulation of cPLA2 activity.

Distinct tyrosine phosphorylation sites in ZAP-70 mediate activation and negative regulation of antigen receptor function

Biochemical and genetic evidence has implicated two families of protein tyrosine kinases (PTKs), the Src- and Syk-PTKs, in T- and B-cell antigen receptor signaling. ZAP-70 is a member of the Syk-PTKs that associates with the T-cell antigen receptor and undergoes tyrosine phosphorylation following receptor activation. Three tyrosine residues, Tyr-292, -492, and -493, have been identified as sites of phosphorylation following T-cell antigen receptor engagement. Utilizing ZAP-70- and Syk-deficient lymphocytes (Syk-DT40 cells), we provide biochemical and functional evidence that heterologous trans-phosphorylation of Tyr-493 by a Src-PTK is required for antigen receptor-mediated activation of both the calcium and ras pathways. In contrast, cells expressing mutations at Tyr-292 or -492 demonstrate hyperactive T- and B-cell antigen receptor phenotypes. Thus, phosphorylation of ZAP-70 mediates both activation and inactivation of antigen receptor signaling.

Phosphorylation of SLP-76 by the ZAP-70 protein-tyrosine kinase is required for T-cell receptor function

Two families of tyrosine kinases, the Src and Syk families, are required for T-cell receptor activation. While the Src kinases are responsible for phosphorylation of receptor-encoded signaling motifs and for up-regulation of ZAP-70 activity, the downstream substrates of ZAP-70 are unknown. Evidence is presented herein that the Src homology 2 (SH2) domain-containing leukocyte protein of 76 kDa (SLP-76) is a substrate of ZAP-70. Phosphorylation of SLP-76 is diminished in T cells that express a catalytically inactive ZAP-70. Moreover, SLP-76 is preferentially phosphorylated by ZAP-70 in vitro and in heterologous cellular systems. In T cells, overexpression of wild-type SLP-76 results in a hyperactive receptor, while expression of a SLP-76 molecule that is unable to be tyrosine-phosphorylated attenuates receptor function. In addition, the SH2 domain of SLP-76 is required for T-cell receptor function, although its role is independent of the ability of SLP-76 to undergo tyrosine phosphorylation. As SLP-76 interacts with both Grb2 and phospholipase C-gamma1, these data indicate that phosphorylation of SLP-76 by ZAP-70 provides an important functional link between the T-cell receptor and activation of ras and calcium pathways.

Choledocholithiasis: comparison of MR cholangiography and endoscopic retrograde cholangiography

PURPOSE

To prospectively compare magnetic resonance (MR) cholangiography with endoscopic retrograde cholangiography (ERC) in the diagnosis of choledocholithiasis.

MATERIALS AND METHODS

Forty-seven patients with suspected choledocholithiasis underwent non-breath-hold, heavily T2-weighted, respiratory-triggered turbo spin-echo MR cholangiography. They then underwent ERC within 5 hours. The results of the two procedures were compared in 45 patients.

RESULTS

The absence of ductal dilatation was shown in 16 patients at MR cholangiography and at ERC. MR cholangiography showed common duct dilatation in 28 of the 29 patients with dilatation shown at ERC. MR cholangiography helped correctly identify 18 of the 19 patients with choledocholithiasis and 22 of the 26 patients without choledocholithiasis. Sensitivity with MR cholangiography was 95%, specificity was 85%, positive predictive value was 82%, and negative predictive value was 96%. Two of the false-positive findings were due to pneumobilia.

CONCLUSION

Non-breath-hold MR cholangiography is as accurate for the evaluation of choledocholithiasis as ERC.

Risk of further ulcer complications after an episode of peptic ulcer bleeding

To identify the risk factors for developing recurrent ulcer complications after recovery from an episode of peptic ulcer bleeding 611 patients admitted with peptic ulcer bleeding were studied. Some 557 (91 per cent) were discharged without operation. A total of 22 patients were lost to follow-up and five were excluded as maintenance H2 blockers were required. Of the remaining 530 patients at risk, 169 (32 per cent) developed another complication (166 bleeding, three perforations) over a median follow-up period of 36 months. Patients with duodenal ulcers at the time of bleeding, previous history of peptic ulcer, previous bleeding, history of dyspepsia longer than 3 months, and a short interval between previous ulcer complications and the index bleed were more likely to develop further complications. Sex, age, smoking, coexisting illness, non-steroidal anti-inflammatory drugs intake and time taken to achieve ulcer healing had no predictive value.

Epinephrine or epinephrine plus alcohol for injection of bleeding ulcers: a prospective randomized trial

BACKGROUND

Rebleeding following epinephrine injection of bleeding peptic ulcers occurs in 10% to 20% of all cases. The addition of a sclerosant has the theoretical advantage of inducing vessel thrombosis and permanent hemostasis.

METHODS

A prospective randomized controlled trial was conducted to compare injections with epinephrine alone or epinephrine plus absolute alcohol in patients with actively bleeding ulcers at endoscopy. Repeat endoscopy was performed 24 hours later; treatment was repeated in the presence of endoscopic signs of rebleeding. Surgery was performed when arterial bleeding could not be controlled endoscopically, clinical rebleeding with hematemesis or shock occurred, or the transfusion total exceeded 8 units.

RESULTS

One hundred sixty patients were enrolled (epinephrine alone, 81; epinephrine and absolute alcohol, 79). They were matched in age, sex, location of ulcers, hemoglobin on admission, shock, and severity of bleeding. Initial hemostasis was comparable: 79 of 81 with epinephrine alone (97.5%) versus 75 of 79 with epinephrine and absolute alcohol (94.9%). No difference was observed between the two with respect to either rebleeding (9 vs 6), need for emergency operation (12 vs 9), transfusion requirement (median, three units vs two units), hospital stay (median, 5 days vs 4 days), mortality (4 vs 7) and ulcer healing at 4 weeks (50 vs 46).

CONCLUSIONS

The additional injection of absolute alcohol after endoscopic epinephrine injection confers no advantage.

Collision tumour of the oesophagus: a challenge for histological diagnosis

An unusual case of mantle cell lymphoma metastasising to squamous cell carcinoma of the oesophagus, in a 62 year old Chinese man, is reported. A histological diagnosis based on examination of a small endoscopic biopsy specimen, in the absence of detailed clinical information, may be difficult, as the lymphoma component can be mistaken for reactive lymphoid infiltrate which is sometimes present adjacent to squamous cell carcinoma. Correlation with the clinical history, careful assessment of the subtle histological changes, and use of ancillary methods such as immunohistochemistry are most helpful in making the correct diagnosis. This case also illustrates further the possible occurrence of lymphomatous infiltrates surrounding other lesions in patients with a previous or concurrent history of lymphoma.

Regulation of antigen receptor signal transduction by protein tyrosine kinases

The past two years have seen further clarification of the early events occurring in antigen receptor signal transduction that are mediated by the immunoreceptor tyrosine-based activation motif (ITAM). The ITAM was shown to be a specific binding site for the ZAP-70/Syk protein tyrosine kinases and the structure of this complex was solved. In addition, possible mechanisms of activation and functions for these kinases were reported. Lastly, genetic studies established the critical importance of these kinases in antigen-receptor signaling and lymphocyte development.

Direct regulation of ZAP-70 by SHP-1 in T cell antigen receptor signaling

The threshold at which antigen triggers lymphocyte activation is set by the enzymes that regulate tyrosine phosphorylation. Upon T cell activation, the protein tyrosine phosphatase SHP-1 was found to bind to the protein tyrosine kinase ZAP-70. This interaction resulted in an increase in SHP-1 phosphatase activity and a decrease in ZAP-70 kinase activity. Expression of a dominant negative mutant of SHP-1 in T cells increased the sensitivity of the antigen receptor. Thus, SHP-1 functions as a negative regulator of the T cell antigen receptor and in setting the threshold of activation.

Clinical validation of the Geriatric Depression Scale (GDS): Chinese version

This study has attempted to validate the Geriatric Depression Scale translated version (Chinese) with a psychiatric outpatient sample (N = 461) of males and females aged 60 or above, from 10 government-maintained psychiatric outpatient clinics between January 1992 and February 1993. Reliabilities and validities were exceptional. Internal consistency reliability was .89 (alpha), and the test-retest reliability was .85 (alpha). Criterion-related (psychiatrist diagnosis) validity was good at .95, and concurrent validity (with CES-D) was .96. Item analysis also confirmed consistency--all 30 items were significantly correlated with the full GDS. However, its sensitivity (70.6%), specificity (70.1%), false negatives (29.4%), and false positives (29.9%), though acceptable, were not as impressive. The overall result has shown that the GDS is generally applicable to the Chinese elderly population and is good for measuring depressive symptoms. The scale can be easily applied in the community by health care professionals. However, further follow-up studies are recommended.

SH2 domain function is essential for the role of the Lck tyrosine kinase in T cell receptor signal transduction

Tyrosine kinase activity is required for signal transduction through the T cell antigen receptor (TCR). The Src family tyrosine kinase Lck appears to play a key role in the initiation of TCR signaling events. We have investigated the role of the phosphotyrosine-binding Src homology-2 (SH2), domain of Lck in TCR signaling. Lck containing a mutation in the phosphotyrosine binding pocket of the SH2 domain was expressed in an Lck-deficient cell line. We found that, in contrast to wild-type Lck, the SH2 domain mutant was unable to restore even the earliest TCR-mediated signaling events. To investigate the role of the Lck SH2 domain, we examined the association of tyrosine phosphoproteins with Lck. The predominant associated phosphoprotein was the ZAP-70 tyrosine kinase, which has also been implicated in the initiation of TCR signaling. In addition, the zeta subunit of the T cell receptor was found to weakly associate with Lck. Further analysis indicated that the SH2 domain of Lck can directly recognize both ZAP-70 and zeta in immunoprecipitates from TCR-stimulated cells. Our findings demonstrate that the SH2 domain of Lck is essential for the initiation of signaling events following TCR stimulation probably as a result of its ability to mediate an interaction between Lck and the ZAP-70 tyrosine kinase and/or the zeta subunit of the T cell receptor.

Granulocytic sarcoma of megakaryoblastic differentiation complicating chronic idiopathic myelofibrosis

We report the development of soft tissue granulocytic sarcoma with megakaryoblastic differentiation in a patient with chronic idiopathic myelofibrosis, which has hitherto been undescribed. Although an artifactual signet ring appearance of the blasts was found in the formalin-fixed tissue and caused diagnostic problems, the histological appearance on B-5 fixed material and immunophenotyping confirmed the diagnosis. Cytogenetic analysis showed 47,XY,+der(1)del(1)(?p13) at initial presentation and 47,XY,del(1)(?13),+der(1)del(1)(?p13) at the time of soft tissue blastic transformation, indicating that partial trisomy 1 might be of pathogenetic significance.

Follicular dendritic cell tumor of the liver. Evidence for an Epstein-Barr virus-related clonal proliferation of follicular dendritic cells

Tumors of the follicular dendritic cell are uncommon, and most occur as primary lymph node tumors. We report a case of primary follicular dendritic cell tumor of the liver that was initially reported as an inflammatory pseudotumor. The neoplasm recurred as two separate tumor masses 30 months after complete resection of the "hepatic inflammatory pseudotumor." It showed a wide spectrum of morphologic features ranging from areas with fascicles of very bland spindle cells amidst a background population of lymphocytes, reminiscent of inflammatory pseudotumor, to areas of dispersed sheets of highly pleomorphic tumor cells with a relative paucity of reactive inflammatory cells. The diagnosis was confirmed by positive immunohistochemical staining with CD21, CD35, R4/23, and Ki-M4 and by ultrastructural demonstration of convoluted interdigitating cell processes joined by desmosomes. The background lymphocytes were oligoclonal, CD8-positive T cells. In situ hybridization for Epstein-Barr virus (EBV)-encoded RNA was positive in the tumor cells in the original and recurrent tumors. More importantly, the cells showed identical episomal clonal EBV on Southern blot analysis, implying that the initial and recurrent tumors are due to clonal proliferation of EBV-positive neoplastic follicular dendritic cells. The tumor cells expressed latent membrane protein but not EBV-encoded nuclear antigen 2 (EBNA2) or ZEBRA. Such gene expression is very similar to that of Hodgkin's disease and nasopharyngeal carcinoma. The strong expression of latent membrane protein restricted to the tumor cells and the clonality of the EBV suggest that the virus may be involved in the pathogenesis of this tumor and not present merely as a "bystander."

Selective use of preoperative endoscopic retrograde cholangiopancreatography in laparoscopic cholecystectomy

BACKGROUND

The management of possible common bile duct (CBD) stones in patients scheduled for laparoscopic cholecystectomy remains controversial.

METHODS

Prospective evaluation of 609 patients who underwent laparoscopic cholecystectomy was carried out in relation to the use of selective preoperative ERCP for detection of common duct stones. Preoperative ERCP was performed if there is or has been (1) cholangitis, biliary pancreatitis, or jaundice; (2) abnormal serum liver tests or (3) ultrasonogram showing a dilated CBD or ductal stones.

RESULTS

A total of 139 patients underwent preoperative ERCP, and cannulation of CBD was successful in 133 patients (96%). CBD stones were found in 60 patients (45%) and extracted after sphincterotomy. High prevalence of CBD stones was noted in patients with acute cholangitis and CBD stones on ultrasonogram. There were six endoscopic sphincterotomy-related complications (complication rate, 4.5%): bleeding (2), pancreatitis (3), retroduodenal perforation (1). No patient required surgery as the result of a complication. The prediction of the occurrence of ductal stones was further analyzed using stepwise logistic regression. Acute cholangitis and CBD stones on ultrasonogram were shown to be independent significant risk factors with odds ratios of 8.9 and 13.5, respectively.

CONCLUSIONS

With selective preoperative ERCP, suspected CBD stones can be identified and removed prior to laparoscopic cholecystectomy.