Latest Research News on Malignant Tumor : Aug – 2020
Metastasis results from preexisting variant cells within a malignant tumor
Clones derived in vitro from a parent culture of murine malignant melanoma cells varied greatly in their ability to produce metastatic colonies in the lungs upon intravenous inoculation into syngeneic mice. This suggests that the parent tumor is heterogeneous and that highly metastatic tumor cell variants preexist in the parental population. 
Magnetic resonance imaging in planning limb-salvage surgery for primary malignant tumors of bone
In defining the linear extent of a malignant tumor in a long bone, radiographs, computerized tomography, and scintigraphy are routinely employed, especially when non-ablative surgery is being considered. The drawbacks of these modalities in defining the true intracompartmental extent of disease within a bone can largely be overcome with the use of magnetic resonance imaging. We did a prospective analysis of magnetic resonance imaging in sixteen consecutive patients with a primary malignant tumor of a long bone, and it showed that this modality has clinical promise of being more precise than the other modalities in defining the true proximal and distal extent of a tumor in a long bone. Coronal images permit easier planning of surgical techniques for salvage of a limb using an allograft than do a multiplicity of transverse images. 
Localized Benign and Malignant Fibrous Tumors of the Pleura
We reviewed 223 localized fibrous tumors of the pleura and divided them histologically into 141 benign and 82 malignant neoplasms. The criteria used for a judgment of malignancy were high cellularity and mitotic activity (more than four mitotic figures per 10 high-power fields), pleomorphism, hemorrhage, and necrosis. The tumors occurred equally in both sexes, most commonly in the sixth to seventh decades of life. Presenting symptoms included chest pain, dyspnea, and cough; they were observed in three-fourths of patients with a malignant tumor. One in every four of these patients had hypoglycemia, clubbed digits, or pleural effusion. Two-thirds of the tumors were attached to visceral pleura, often by a pedicle. The rest arose from the parietal pleura of the chest wall, diaphragm, or mediastinum. Neoplasms in these atypical sites, together with fissural lesions and tumors “inverted” into peripheral lung, were more often malignant. Most neoplasms measured 5–10 cm and weighed 100–400 g. Microscopically, the “patternless pattern,” or hemangiopericytic type, was seen in the majority of cases, and mixed patterns were seen in nearly 40% of tumors. Of the 169 tumors where follow-up was available, all of the benign and 45% of the malignant tumors were cured by simple excision. Patients surgically cured of a malignant neoplasm had pedunculated or well-circumscribed lesions. However, 55% of patients with malignant tumors succumbed to their disease secondary to invasion, recurrence, or metastasis. Resectability is the single most important indicator of clinical outcome. No tumor expressed epithelial differentiation, either immunohistochemically or ultrastructurally; therefore, we favor the term “localized fibrous tumor” of pleura instead of “localized mesothelioma.” 
Histopathological Pattern of Pediatric Malignant Tumors and Survival Rate at Kilimanjaro Christian Medical Centre, Tanzania from 2013 to 2015
Background: Childhood malignant tumors are among diseases that cause death to children below 14 years. Although it is the second most common cause of death in children in developed countries, its magnitude in Africa is not well known.
Aim: To determine the proportion of pediatric malignant tumors and the immediate outcome among children attending Kilimanjaro Christian Medical Centre in Tanzania.
Study Design: Retrospective – hospital based study.
Place and Duration: Kilimanjaro Christian Medical Centre, Pathology department, 3 years.
Methodology: Microscopic slides from January 2013 to December 2015 were retrieved from archives and evaluated at a magnification of 40x, 100x and 200x for histological features, diagnosis and disease grading. The findings were confirmed by the pediatric pathologist and concluded on the diagnoses and the grade. The tumors were graded into well-differentiated and undifferentiated. Parents/guardians were contacted through phone calls to establish progress of their children to assess the six-month survival rate.
Results: Among 84 studied patients’ slides, 43 (51.2%) were from males with the median (IQR) age of 4.5 (2.3-9.3) years while 50 children (59.5%) were under five years of age. Retinoblastoma 21 (25%) was the most common malignant tumor followed by Squamous cell carcinoma and Sarcoma comprising 13 (15.5%) each. Among 75 children other than patients with leukemia, 42 (56.0%) had well differentiated and 33 (44.0%) had undifferentiated malignant tumors. Forty-one (97.6%) of the patients with well-differentiated malignant tumors survived within six months from the date the specimen was taken. The overall six-month survival rate was 84.5%. Thirteen patients (15.5%) died during the six-month period of follow up.
Conclusion: Retinoblastoma was the most common malignant tumor affecting children <14 years in northern Tanzania. The overall six-month survival rate was high when early detection of childhood malignancies is practicable. 
Malignant Retroperitoneal Extra-Gastrointestinal Stromal Tumor: A Case Report
Context: Extragastrointestinal stromal tumors (EGIST) are extremely uncommon neoplasm. To the best of our knowledge, only one retroperitoneal EGIST case has been reported in Oncolgy, in 2005ï¼ˆPubMed search result).
Case Report: A 67-year old female patient presented with epigastric discomfort, dyspepsia, and anemia. Ultrasonographic examination of the abdomen showed the location of the tumor was between the tail of the pancreas and the spleen (retroperitoneal), it was variable in size of 12.3cm×7.2cm×14cm. Color Doppler Flow Imaging (CDFI) showed no flow signals with arterial-venous doppler spectrum in the massesï¼ŽContrast-enhanced computed tomography of the abdomen revealed a heterogeneously enhancing mass (8.23cm×14.2cm) and abundant blood supply of the tumor. The patient underwent gastroscopes-guided biopsy from the fundus of stomach for pathologic diagnosis and the result indicated chronic superficial gastritis. A complete gross excision was performed. Retroperitoneal tylectomy, left hepatic lobectomy, enterolysis, and liver biopsy were performed. Two weeks post operation, the patient was discharged without any postoperative problems. The final diagnosis of retroperitoneal EGIST was confirmed by histopathological examination and immunohistochemical findings (CD117 positivity).
Conclusion: We report a very rare case of retroperitoneal EGIST. Although the Ultrasonographic examination, computer tomography and endoscopy examination did not confirm the final diagnosis, they are complemented to each other in order to identify the exact location of the tumor. EGIST should be considered in the differential diagnosis of solid masses of abdomen on cytology and immunohistology. 
 Fidler, I.J. and Kripke, M.L., 1977. Metastasis results from preexisting variant cells within a malignant tumor. Science, 197(4306), pp.893-895.
 Sundaram, M.U.R.A.L.I., McGUIRE, M.H., Herbold, D.R., Wolverson, M.K. and Heiberg, E., 1986. Magnetic resonance imaging in planning limb-salvage surgery for primary malignant tumors of bone. JBJS, 68(6), pp.809-819.
 England, D.M., Hochholzer, L. and McCarthy, M.J., 1989. Localized benign and malignant fibrous tumors of the pleura: a clinicopathologic review of 223 cases. The American journal of surgical pathology, 13(8), pp.640-658.
 Killenga, S., Msuya, S., Philemon, R., Mremi, A. and T. Mmbaga, B. (2016) “Histopathological Pattern of Pediatric Malignant Tumors and Survival Rate at Kilimanjaro Christian Medical Centre, Tanzania from 2013 to 2015”, Journal of Cancer and Tumor International, 4(2), pp. 1-8. doi: 10.9734/JCTI/2016/29031.
 Abuduwayite, R., Muhemaiti, A., Biekemituofu, H. and Mohemaiti, P. (2012) “Malignant Retroperitoneal Extra-Gastrointestinal Stromal Tumor: A Case Report”, Journal of Advances in Medicine and Medical Research, 2(2), pp. 142-149. doi: 10.9734/BJMMR/2012/832.