PD-L1 Expression in colorectal carcinoma and its correlation with clinicopathological parameters, microsatellite instability and BRAF mutation.

CONTEXT: : Programmed cell death ligand-1 (PD-L1) is the key inhibitor of the cytotoxic immune response thus causing progression of tumors and adverse prognosis in many malignancies. OBJECTIVE: The current study investigates PD-L1 expression in colorectal carcinoma and its correlation with clinicopathological parameters, microsatellite instability, and BRAF mutation. MATERIAL AND METHODS: 110 cases of colorectal carcinoma were evaluated for PD-L1 expression using SP263 clone in tissue microarray. Clinico-pathological characteristics and survival data were correlated with PD-L1 expression analyzed at different cut-offs of ≥1%, ≥10% and ≥50% in tumor cells and tumor infiltrating lymphocytes along with its correlation with BRAF expression and microsatellite instability status in these cases. RESULTS: Mean age was 49 years with male to female ratio of 1.5:1. 52.7% cases presented with stage 3/4 disease and 14.7% with >10 cm tumor size. Tumor cells expressed PD-L1 in 40% and TILs in 45.4% cases at a cut off of ≥1% was 17.3%, at ≥10% was 15.5% and at ≥50% was 7.3%. Significant association was seen between tumor proportion score (TPS) and increasing age, histological type, histological grade, tumor size, higher T stage (p = 0.03), TILs (p = 0.04), lymph vascular invasion, and perineural invasion. PDL-1 correlated with BRAF expression and microsatellite instability (MLH-1/PMS-2 expression loss). The overall survival was significantly higher (p < 0.001) with negative PDL1 expression in cases of colorectal carcinoma. CONCLUSIONS: Immunotherapy may be used as potential therapeutic option in colorectal carcinoma cases showing microsatellite instability and BRAF mutations which show poor response to conventional chemotherapy regimen and anti-EGFR therapy.

Microsatellite Instability in Sporadic Colorectal Malignancy: A Pilot Study from Northern India.

BACKGROUND: Three molecular pathways are described as the genetic basis of colorectal tumorigenesis. Among these, microsatellite instability (MSI) has shown greatest promise in serving as a biomarker to determine disease aggression by tumour biology, recurrence, and response to chemotherapy. METHODOLOGY: This prospective observational pilot study included patients of colorectal cancers, in a population subset coming to a tertiary care hospital in northern India, who were operated with curative or palliative intent over a period of one year and followed up for a maximum of 55 months. The post-operative pathological assessment was done for MSI status using PCR technique, and an attempt was made to evaluate its correlation with conventional clinical and histological parameters, early recurrences, disease-free survival and overall survival in comparison to MSS type tumours in sporadic cases of colorectal malignancies. RESULTS: Out of 38 patients of colorectal cancer, 26 were included in the study. Male to female ratio was 7:6 (n=14:12). Mean age of presentation was 48±14.2 years. Incidence of MSI was n=4 (15.4%). On subgroup analysis, age of presentation (p=0.044) and evidence of perineural invasion (p=0.017) was found to have significant statistical association with MSI tumour biology. Recurrence was seen in seven of the seventeen patients who previously had no synchronous or metastatic disease (41.2%). The mean disease-free survival for MSS was 21.32 months and was 25.25 months for MSI group which was statistically insignificant (p = 0.277). Out of four MSI tumour biology patients one was alive and without recurrence at 47 months. While the other two were alive and without recurrence till 27 months of follow-up.   Conclusion: Age and perineural invasion showed statistically significant association with MSI tumour biology. Due to the small sample size statistical significance was not established with site, recurrence rate, DFS and OS.

Polymeric locking clips [Hem-o-lok] versus Metallic clips in elective Laparoscopic Cholecystectomy: A Retrospective study of 1496 patients.

Background Laparoscopic cholecystectomy is one of the most commonly performed operation. Various methods for securing the cystic artery and cystic duct are described in literature. We aim to compare intra-operative and early post-operative outcomes of laparoscopic cholecystectomy using polymeric locking Hem-o-lok clips versus metallic ligaclips . Patients and Methods Retrospective study of prospectively maintained single institutional data including all consecutive patients who underwent elective laparoscopic cholecystectomy from 2013 to 2018. Patients in whom metallic ligaclips were used were grouped as Group I and those with Hem-o-Lok were grouped as Group II. The early post-operative outcomes of the two groups were compared. Results Total 1496 patients were included in the study; 836 patients in Group I and 660 in Group II. Study included 29.1% males and 70.9% females with mean age of 43.6 years. Hem-o-lok clip was better in securing wide cystic duct compared to metallic clips. Metallic clip failed to secure 8 out of 44 wide cystic duct compared to 0 out 70 with Hem-o-lok clips (p=0.002). The post-operative outcomes of both groups were comparable. There were no cystic duct leak, post- operative bleeding or major bile duct injuries in either group. Conclusion Use of Hem-o-lok clip is safe in laparoscopic cholecystectomy due to ease of application and security. Hem-o-lok is more useful in patients with thick and wide cystic duct which are difficult to secure with metallic clips with low risk of leak. Key words: Laparoscopic Cholecystectomy, Hem-o-lok clip, Metallic clip, Wide cystic duct.

Predictors and Outcomes of Pancreatic Fistula Following Pancreaticoduodenectomy: a Dual Center Experience.

Fistula following leaked pancreatico-enteric anastomosis is a common, potentially lethal complication of pancreaticoduodenectomy (PD). Early assessment and prediction of its occurrence can improve postoperative outcomes. Various perioperative factors were analyzed for its contribution to clinically relevant postoperative pancreatic fistula (crPOPF). Also, the difference in clinical outcomes of patients with and without fistula was studied. Sixty-seven patients undergoing PD for malignancies were analyzed during 3-year period in a dual-institutional study. Various preoperative, intraoperative, and postoperative factors were assessed. The incidence and severity of POPF and its association with the development of other post-PD complications were observed. Patients with and without POPF were divided into groups and compared with univariate and multivariate analyses, to identify significant contributing factors. Clinically relevant POPF was present in 20.9% cases. crPOPF contributed to delayed gastric emptying, albeit insignificant (p = 0.403), but was significantly associated with increased incidence of post-pancreatectomy hemorrhagic (p = 0.005) and infectious complications (p = 0.013). Soft pancreas (p = 0.024), intraoperative blood loss (p = 0.045), blood transfusion (p = 0.024), and fistula risk score (p = 0.001) were significant predictors of crPOPF. First postoperative day (POD1) drain fluid amylase (DFA) values at cut-off of 1336 U/L (AUC = 0.871; p < 0.001) significantly predicted crPOPF with good sensitivity and specificity. POD1 DFA was only factor significant on multivariate analysis (p = 0.014). There was no significant difference in overall survival between groups. crPOPF results in significant post-pancreatectomy hemorrhagic and septic complications, along with increased mortality. It can be accurately predicted by several preoperative and intraoperative factors. POD1 DFA can independently predict crPOPF development.

Incidental Gallbladder Carcinoma in Gallbladder Polyps: Challenges of Gallbladder Malignancy for an Endemic Population.

BACKGROUND: Gallbladder polyps are considered pre-malignant lesions of gallbladder carcinoma. This study aims to highlight the role of early cholecystectomy in the management of gallbladder polyps in an endemic population. METHODS: A retrospective analysis of 2,076 lap cholecystectomy procedures performed at the Department of Surgical Gastroenterology at a tertiary referral centre in Northern India was conducted and incidental malignancy in gallbladder polyps analysed. The 8th edition of the American Joint Committee on Cancer for tumour-node-metastasis (TNM) staging of gallbladder carcinoma was used. RESULTS: Of 54 patients with gallbladder polyps, 53 had benign histology and one had malignant cells in the lamina propria suggestive of T1a adenocarcinoma. The patient with the malignant polyp was older (57 years old) than the patients in the non-cancer group, which had a mean age of 45 (P = 0.039). The size of the malignant polyp was approximately 4 mm, significantly smaller than the average 7.9 mm size of the benign polys (P = 0.031). CONCLUSION: Cholecystectomy needs to be considered early in the management of small-sized gallbladder polyps, particularly in areas endemic for gallbladder carcinoma.

Comparative Study of Effects of Intraoperative Use of Positive End-Expiratory Pressure, Intermittent Recruitment Maneuver, and Conventional Ventilation on Pulmonary Functions during long-Duration Laparotomy.

BACKGROUND: With an increase in the duration of general anesthesia, there is a gradual deterioration in pulmonary functions. Intraoperative atelectasis is the major cause of deterioration in pulmonary functions. This study was performed to compare and determine the best ventilatory strategy among conventional ventilation, application of positive end-expiratory pressure (PEEP), and intermittent recruitment maneuver. MATERIALS AND METHODS: Seventy-five patients were divided into three groups each of 25 patients. In the first group (zero positive end-expiratory pressure [ZEEP]), we have applied zero PEEP intraoperatively. In the second group (PEEP), we have applied PEEP of 6 cm of H2O. In the third group (intermittent lung recruitment maneuver [IRM]), we have done intermittent recruitment maneuver intraoperatively. Pulmonary functions were analyzed by partial pressure of oxygen (PaO2)/fraction of inspired oxygen (FiO2) ratio (P/F) and static lung compliance (Cstat). RESULTS: While comparing the mean P/F ratio between the groups, a significant decrease in P/F ratio of the ZEEP group was found from 90 min after induction up till the end (i. e. 24 h after extubation) of our observations as compared to both the PEEP and IRM groups. However, it did not differ (P > 0.05) between the PEEP and IRM groups at all time points on statistical analysis. On comparing the mean of Cstat between the groups, there was a significant decrease in lung compliance of the ZEEP group as compared to both the PEEP and IRM groups at all time points. However, like P/F ratio, compliance was also found to be statistically insignificant between the PEEP and IRM groups. CONCLUSIONS: Pulmonary functions are relatively preserved with application of either PEEP or doing intermittent recruitment maneuver.

Substrate and Stereochemical Control of Peptidoglycan Cross-Linking by Transpeptidation by Escherichia coli PBP1B.

Penicillin binding proteins (PBPs) catalyzing transpeptidation reactions that stabilize the peptidoglycan component of the bacterial cell wall are the targets of ß-lactams, the most clinically successful antibiotics to date. However, PBP-transpeptidation enzymology has evaded detailed analysis, because of the historical unavailability of kinetically competent assays with physiologically relevant substrates and the previously unappreciated contribution of protein cofactors to PBP activity. By re-engineering peptidoglycan synthesis, we have constructed a continuous spectrophotometric assay for transpeptidation of native or near native peptidoglycan precursors and fragments by Escherichia coli PBP1B, allowing us to (a) identify recognition elements of transpeptidase substrates, (b) reveal a novel mechanism of stereochemical editing within peptidoglycan transpeptidation, (c) assess the impact of peptidoglycan substrates on ß-lactam targeting of transpeptidation, and (d) demonstrate that both substrates have to be bound before transpeptidation occurs. The results allow characterization of high molecular weight PBPs as enzymes and not merely the targets of ß-lactam acylation.

Factors predicting recovery of liver function after percutaneous drainage in malignant biliary obstruction: the role of hospital-acquired biliary sepsis.

AIM OF THE STUDY: Prolonged cholestasis adversely affects liver function. Hepatic functional recovery is mandatory prior to any surgical or medical intervention. Serum bilirubin levels correlate well with, and are a surrogate marker for, hepatocyte function. We aimed to ascertain factors responsible for slow decline of bilirubin and delayed recovery of liver function following percutaneous drainage in malignant biliary obstruction. MATERIAL AND METHODS: Sixty-seven patients with malignant jaundice who underwent percutaneous biliary drainage (PTBD) were followed until they achieved target bilirubin ≤ 3 mg/dl. According to duration, patients were divided into early (≤ 6 weeks, n = 43) and late (> 6 weeks, n = 24) groups. Various clinical, tumour-related and procedure-related factors were analysed for their contribution to delayed recovery with the χ2 or t-test. Multi-variate logistic regression analysis was used to predict independent associations. RESULTS: Gallbladder cancer presenting with type I block was the commonest pathology. Overall demographic, clinical, tumour characteristics and procedural details were comparable between groups. Duration of jaundice (p = 0.026), liver involvement (p = 0.041), baseline total (p = 0.001) and direct bilirubin levels (p < 0.001), positive bile cultures with hospital-acquired bacteria (p = 0.031) were significant factors on univariate analysis. Bacterial growth was significantly greater following repeated biliary manipulations. The commonest organisms were Pseudomonas and Citrobacter spp. Number of re-instrumentations, post-procedural biliary sepsis and native biliary organisms were non-contributory. No factor was significant on multivariate analysis. CONCLUSIONS: Factors directly linked to extent and duration of disease are validated as significant contributors to functional recovery after biliary drainage. Biliary sepsis with hospital-acquired organisms, especially following re-interventions is a significant modifiable risk-factor affecting bilirubin decline.

Is Final Histopathological Examination the Only Diagnostic Criteria for Xanthogranulomatous Cholecystitis?

BACKGROUND: Xanthogranulomatous cholecystitis (XGC) is an uncommon inflammatory disease of gallbladder (GB) and can mimic GB cancer in extensive form. This study aims to assess the predictability of XGC on the basis of clinical presentation, laboratory tests, and radiological or intraoperative findings on frozen section analysis. MATERIALS AND METHODS: This is a retrospective study, conducted over a period of 4 years from October 2013 to November 2017. In this study, all patients with histopathological reports of XGC, who underwent cholecystectomy or a radical cholecystectomy, were included. Clinical records of these patients were reviewed for clinical features, laboratory tests, and findings on radiological imaging. RESULTS: Out of 700 consecutive cholecystectomies reviewed, 34 had histologically proven XGC (4.85%). Two patients had simultaneous presence of GB carcinoma with XGC. The most common presenting symptoms were right upper quadrant pain in 32 (94%) patients, jaundice in 9 (36%) patients, and fever in 5 (14%) patients. The most common radiological finding was cholelithiasis in 85.2% of cases. Thick-walled GB was present in 79.4% of patients; irregular wall thickening was present in 20.5% of patients. Intramural nodule was present in two patients, whereas hepatic invasion was observed in 11% and pericholecystic infiltration was present in 8.8% of patients. Regional lymphadenopathy was present in 9 (26.4%) patients. CONCLUSION: Clinical presentation and laboratory parameters were unequivocal due to considerable overlap. Despite recent advances in radiology, none have significant sensitivity and specificity to accurately diagnose XGC preoperatively. Intraoperative frozen section can add to the diagnosis with limited accuracy. The diagnosis of XGC can be confirmed only on histopathological examination.

Hydrolysis of peptidoglycan is modulated by amidation of meso-diaminopimelic acid and Mg2+ in Bacillus subtilis.

The ability of excess Mg2+ to compensate the absence of cell wall related genes in Bacillus subtilis has been known for a long time, but the mechanism has remained obscure. Here, we show that the rigidity of wild-type cells remains unaffected with excess Mg2+ , but the proportion of amidated meso-diaminopimelic (mDAP) acid in their peptidoglycan (PG) is significantly reduced. We identify the amidotransferase AsnB as responsible for mDAP amidation and show that the gene encoding it is essential without added Mg2+ . Growth without excess Mg2+ causes ΔasnB mutant cells to deform and ultimately lyse. In cell regions with deformations, PG insertion is orderly and indistinguishable from the wild-type. However, PG degradation is unevenly distributed along the sidewalls. Furthermore, ΔasnB mutant cells exhibit increased sensitivity to antibiotics targeting the cell wall. These results suggest that absence of amidated mDAP causes a lethal deregulation of PG hydrolysis that can be inhibited by increased levels of Mg2+ . Consistently, we find that Mg2+ inhibits autolysis of wild-type cells. We suggest that Mg2+ helps to maintain the balance between PG synthesis and hydrolysis in cell wall mutants where this balance is perturbed in favor of increased degradation.

Reconstruction of diaminopimelic acid biosynthesis allows characterisation of Mycobacterium tuberculosis N-succinyl-L,L-diaminopimelic acid desuccinylase.

With the increased incidence of tuberculosis (TB) caused by Mycobacterium tuberculosis there is an urgent need for new and better anti-tubercular drugs. N-succinyl-L,L-diaminopimelic acid desuccinylase (DapE) is a key enzyme in the succinylase pathway for the biosynthesis of meso-diaminopimelic acid (meso-DAP) and L-lysine. DapE is a zinc containing metallohydrolase which hydrolyses N-succinyl L,L diaminopimelic acid (L,L-NSDAP) to L,L-diaminopimelic acid (L,L-DAP) and succinate. M. tuberculosis DapE (MtDapE) was cloned, over-expressed and purified as an N-terminal hexahistidine ((His)6) tagged fusion containing one zinc ion per DapE monomer. We redesigned the DAP synthetic pathway to generate L,L-NSDAP and other L,L-NSDAP derivatives and have characterised MtDapE with these substrates. In contrast to its other Gram negative homologues, the MtDapE was insensitive to inhibition by L-captopril which we show is consistent with novel mycobacterial alterations in the binding site of this drug.

Granulocytic sarcoma presenting as an orbital mass: report of two cases.

Granulocytic sarcoma is a rare variant of a myeloid malignancy, which shows an extra-medullary tumour mass which is composed of myeloblasts and myeloid precursors with varying degrees of differentiation. It occurs most commonly in bone, periosteum, soft tissue, lymph nodes, and skin; although it can occur anywhere throughout the body. Here, we are reporting two cases of orbital granulocytic sarcoma in children, which presented clinically with proptosis and periorbital swellings, which were first diagnosed by Fine Needle Aspiration Cytology (FNAC). Later, peripheral blood and bone marrow aspirate examinations revealed the evidence of Acute Myeloid Leukaemia (AML). These cases are being documented to demonstrate the utility and diagnostic accuracy of FNAC in evaluation of this entity, in cases of unsuspected AML. Recognition of this rare entity is important, because giving an early aggressive chemotherapy can cause regression of the tumour and thus improve the patient survival.

Endodermal sinus tumor of vagina in infants.

Endodermal sinus tumor (or Yolk Sac tumor) of the vagina is a rare malignant germcell tumor which is seen exclusively in children younger than 3 years of age. We report two cases of endodermal sinus tumor of the vagina. In both cases no radiological investigation was done and serum alpha-fetoprotein was elevated. The histopathological examination of both the tumor masses revealed vaginal endodermal sinus tumor. Periodic-acid-Schiff stain with diastase showed diastase resistant hyaline globules. These findings confirmed the diagnosis of endodermal sinus tumor in both cases. Vaginal endodermal sinus tumor is both locally aggressive and capable of metastasis. The serum alpha-fetoprotein level is a useful marker for diagnosis and monitoring the recurrence of vaginal endodermal sinus tumor in infants. Early detection and therapy is important because of its aggressive nature and good response to chemotherapy.

A glomus tumour arising from the flexor aspect of the forearm: a case report with review of the literature.

A 45 year old male patient presented with the complaint of a purplish nodular painful swelling on the flexor aspect of the left forearm of five years duration. A radiological examination of the lesion was not done prior to its excision. A biopsy was done and it was sent for a histopathological examination. The biopsied tissue was single, irregular, firm and globular, it measured 0.5 x 0.5cm in size and it was processed in two halves Its microscopic examination showed a well circumscribed area which comprised of sheets and nodules of monomorphic round cells with slightly vesicular, round nuclei and an acidophilic cytoplasm, amongst which were interspersed numerous blood vessels, many of which were dilated and congested, along with numerous lymphatic channels which were filled with lymph. Immunohistochemistry for SMA, CEA and CD 34 was advised, out of which only SMA turned out to be strongly positive and a final diagnosis of a Glomus tumour was made.

Myoepithelioma breast: clinically masquerading as breast carcinoma.

Pure myoepithelioma of breast is an extremely rare tumor. Only a few cases have been reported in the literature so far. A 30-year old female presented with a large fungating mass arising from the areolar region of her right breast of six months duration. A clinical diagnosis of breast carcinoma was made and a mastectomy was performed. The specimen measured 23×22×9 cm with attached skin, and showed a large white ulcerated growth with areas of necrosis and hemorrhage. No normal breast tissue, nipple or areolar region was seen. Histopathological examination showed oval to spindle cells arranged in fascicles and bundles with whorling pattern in places showing mild pleomorphism with oval to spindle-shaped vesicular nuclei, prominent eosinophilic nucleoli, eosinophilic cytoplasm and clear cell changes in places, along with perivascular hyalinization and collagenization. Differential diagnosis of pleomorphic hyalinizing angiectatic tumor, solitary fibrous tumor, perivascular epithelioid cell tumor, mammary type myofibroblastic tumor and myoepithelioma were all considered. Immunohistochemistry for vimentin, smooth muscle actin, calponin, caldesmon, p63, epithelial membrane antigen, S-100, CD-31, CD-34, muscle specific antigen, myogenin, desmin, and pancytokeratin was carried out. On the basis of positive staining for vimentin, actin, p63 (nuclear), calponin and caldesmon (focal), a final diagnosis of myoepithelioma was considered; however, cytokeratin negativity was an unusual finding. This case was considered worthy of documentation because of its rarity, and because it highlights the importance of proper clinical examination and radiological examination to prevent misdiagnosis.