Central nervous system lymphomas: a histologic and immunophenotypic analysis

Objective: To observe the spectrum of non-Hodkin’s lymphomas involving the central nervous system including morphological subtypes and immunophenotypic status. Setting: Retrospective analysis of eleven years (1986 to 1996) data from surgical pathology files of Department of Pathology. Results: orty-three cases of non-Hodgkin’s lymphomas were diagnosed during the period of eleven years (from 1986 to 1996), all of which were diffuse types. A total of 1177 Central Nervous CNS biopsies were examined, out of which 937 cases were diagnosed as CNS neoplasms, the remaining were non-neoplastic in nature. Among 937 CNS neoplasms, 43 cases (4.6%) were reported as non-Hodgkin’s lymphomas. As most of the cases were outside referrals, the primary or secondary nature of the lymphomatous process could not he assessed. Seventeen cases were intracranial, while 26 cases were spinal in location. Majority of the intracranial Eymphomas were hiopsied from the cereherum (12 cases). Male to female ratio was 1:2. The median age for intracranial lvmphomas was 50 years and for spinal lymphomas 29 years. There were 16 cases (37%) of diffuse large cell lymphomas; 7 cases (16%) of diffuse mixed small and large cell lymphomas; 3 cases (7%) of diffuse large cell immunoblastic lvmphomas; 2 cases (4.6%) of lymphoblastic lymphomas and diffuse small non-cleaved cell lymphomas and one case of small Iyrnphocytic lymphoma and diffuse small cleaved cell Ivmphoma. One case of T cell rich B cell lvmphoma was also diagnosed in the thoracic spine as primary extranodal lymphoma. Eight cases were unclassifiable and in 2 cases the features were suggestive of lymphoma. Immunophenotypic analysis was performed in 20 cases, however, in 2 cases the results were inconclusive. Fifteen cases (83%) showed immunoreactivity for B cell markers and 3 cases showed T cell phenotype out of which one case was lymphoblastic lymphoma. Conclusion: CNS lymphomas were uncommon tumors and comprised 4.6% of the total CNS neoplasms in our study. Moreover, these CNS lymphomas accounted for 2.2% of the total non-Hodgkin’s lvmphomas, including both nodal and extranodal. There was a higher incidence of location of these lymphomas within the spinal cord than brain. Most of the lymphomas were of intermediate or high grade (75%) according to the working phenotype in 84% 3f the lymphomas, in which it was formulation. lmmunophenotypical status revealed B-cell teste

On provision of resilient connectivity in cognitive unmanned aerial vehicles

Mobile ad-hoc network (MANET) can be established in the areas/scenarios where the infrastructure networks are either out of service or no more available. MANETs have a lot of applications in sensor networks. Generally, a MANET deploys mobile ground nodes to set up a network. However, there can be some severe scenarios such as flood, battlefield, rescue operations, etc. where these ground nodes cannot be deployed. In such cases, a network of unmanned aerial vehicles (UAVs) can be a more viable option. Normally, UAVs operates on IEEE L-Band, IEEE S-Band or ISM band. These bands are already overcrowded, therefore, UAVs will face the problem of the spectrum scarcity. To resolve this issue cognitive radio (CR) is a most promising technology. Hence, in this work, we focus on CR based UAVs. As CR is based on opportunistic spectrum access, therefore, it is quite possible that all UAVs do not have one single channel available to communicate with each other. They need to form clusters for their communication depending on the availability of the channel. However, channel availability is intermittent because of opportunistic spectrum access. This may result in reforming of the cluster again and again. To avoid this frequent re-clustering and to maintain connectivity among the UAVs, in this paper, we present a resilient clustering technique with a concept of introducing a backup channel for each cluster. Simulation results show the significance of the proposed technique

Frequency and Characteristics of Breast lymphomas presenting to a tertiary care hospital, Pakistan

Objective: To assess the relative frequency of (primary and secondary) mammary lymphomas presenting to a tertiary care hospital, Pakistan and its categorization according to WHO classification of lymphoid neoplasms. Methods: All NHLs (nodal and extra nodal) diagnosed in the section of histopathology during 1992-2004 were retrieved and reviewed. All patients (n=30) diagnosed with lymphomatous involvement of the breast were selected. Distinction between primary and secondary breast lymphomas was not made owing to lack of availability of clinical information. Results: A total of 5637 breast malignancies were diagnosed in our department during the study period of 10 years and the total number of NHLs (Nodal and extra Nodal) was 2632. Thirty (n=30) patients accounting for 1.13% were diagnosed to have lymphomatous involvement of the breast. The Female to Male ratio was13.5:1; age range was 12-92 years with a median age of 43 years (Mean age 46.5 years and Standard deviation of age was 16.88 years). The sites of the lesions were the right breast in 11 cases (37.93%), left breast in 9 cases (31.03%) and both breasts in 2 cases (6.89%), while the location of 8 masses (27.58%) was unknown. Immunohistochemical studies were negative for cytokeratins (MNF and Cam 5.2) in all cases. All cases of DLBCL expressed B cell lineage antigens and were positive for LCA and Pan B (CD20 and 79a). Conclusion: We concluded that breast lymphomas represent 1.13% of all NHL and 0.5% of all breast malignancies in this study. The most frequent morphologic type was diffuse large B-cell lymphoma. As patients with primary breast lymphoma have a better prognosis than those with carcinoma of the breast or patients with extranodal lymphomas, a multidisciplinary approach including surgery, radiotherapy, and chemotherapy when needed would result in a more favourable outcome

Colorectal Carcinoma, Extent and Spread in our Population. Resection Specimens give Valuable Information

Objective: To acquire information about the extent and spread of colorectal carcinomas in our population by examining colon and colorectum resection specimens received.Methods: All colon and colorectum resection specimens received in the section of Histopathology, Aga Khan University Hospital, Karachi from January 1, 2003 to July 31, 2003 were included in the study.Results: Eighty five resection specimens were received during the study period, 69.41% patients were males, and 30.59% were females. The mean age for males was 49 years and for females 48 years. Tumor location was in left colon (58.82%), and in right colon (41.18%). The average size of the lesions in largest dimension was 5.5cms. Majority (83.53%) were colorectal adenocarcinomas, 71.76% cases were grade II, 16.47% were grade I, and 11.76% were grade III. Most cases (85.88%) infiltrated full thickness of the bowel wall extending into the pericolonic fat. Vascular invasion was seen in 16.47% cases. Radial margin was positive in 23.08% of rectal carcinomas and 57.65% cases showed lymph node metastases.Conclusion: The findings in our study demonstrate that the disease is usually very advanced with extension into pericolonic fat and positive lymph nodes. Thus, the early detection and resection (while the disease is still in an early stage) are essential in our population using better surgical techniques, for proper staging of these tumor

Histological pattern of central nervous system neoplasms

Objective: To see in a large series of patients the histological pattern of CNS neoplasms and to provide a comprehensive data about the frequency of CNS neoplasms in Pakistani patients and to give a clearer idea about their prevalence. Method: Retrospective study of all consecutive cases of CNS neoplasms diagnosed at The Aga Khan University Hospital (AKUH) between 1st January 1994 and 31st December, 1999. Setting: The section of Histopathology, AKUH, Karachi. Observation: Our series included a large number of cases i.e., 1110 . There are very few local studies on CNS tumours and none so large . Our data was correlated with published Western and Pakistani data . Glial tumours were the commonest primary CNS neoplasms followed by meningiomas . Among glial tumours , astrocytomas comprised the largest group and the majority were high grade (Ill and IV ) astrocytomas. Percentages of anaplastic oligodendrogliomas and ependymomas were also significant. Male to female ratio was 1.6:1. However, meningiomas were more common in females. Almost half of the CNS tumours in patients 15 years or younger were in the posterior cranial fossa . Metastatic tumours were much lower as compared to the West. Conclusion: Except for the high percentages of anaplastic oligodendrogliomas and ependymomas and the low percentage of metastatic tumours, most of our findings roughly correspond with the published data

Immunohistochemical Estrogen receptor determination in human Breast carcinoma: correlation with histologic differentiation and age of the patients

An immunohistochemical assay for the measurement of estrogen receptor (ER) has been evaluated on 290 consecutive human breast biopsy and mastectomy specimens in the year 1992 at The Aga Khan University Hospital laboratories. Immunohistochemical localization of estrogen receptor on frozen/paraffin section was scored in a semi-quantitative fashion incorporating both the intensity and the distribution of specific staining. Histologic grading of the tumour was performed according to Bloom’s method. In this study, 21% of the tumours were estrogen receptor negative, 15% were weak positive, 25% intermediate positive and 39% strong positive. Fifty percent of the well differentiated tumours showed strong ER positivity against 27% of the poorly differentiated tumours. Seventy eight percent of all negative estrogen receptors were in patients younger than 50 years of age (pre-menopausal group), while 52% of strong estrogen receptor positivity was observed in patients older than 50 years (post- menopausal). This study demonstrates the value of immunohistochemical method to determine the ER status in patients with advanced breast cancer