Implication of Microsatellite Instability Pathway in Outcome of Colon Cancer in Moroccan Population.

BACKGROUND: Tumors with microsatellite instability (MSI tumors) have distinct clinicopathological features. However, the relation between these tumor subtypes and survival in colon cancer remains controversial. The aim of this study was to evaluate the overall survival (OS) in patients with MSI phenotype, in FES population. METHODS: The expression of MMR proteins was evaluated by immunohistochemistry for 330 patients. BRAF, KRAS, and NRAS mutations were examined by Sanger sequencing and pyrosequencing methods. The association of MSI status with a patient's survival was assessed by the Kaplan-Meier method and log-rank test. RESULTS: The mean age was 54.6 years (range of 19-90 years). The MSI status was found in 11.2% of our population. MSI tumors were significantly associated with male gender, younger patients, stage I-II, right localization, and a lower rate of lymph node and distant metastasis. The OS tends to be longer in MSI tumors than MSS tumors (109.71 versus 74.08), with a difference close to significance (P = 0.05). CONCLUSION: Our study demonstrates that MSI tumors have a particular clinicopathological features. The results of survival analysis indicate that the MSI status was not predictive of improved overall survival in our context with a lower statistical significance (P = 0.05) after multivariate analysis.

Thymic large cell neuroendocrine carcinoma - a rare and aggressive tumor: a case report.

BACKGROUND: Neuroendocrine tumors are a large group of tumors with a wide spectrum of behavior, affecting mainly the digestive system and the lung. The thymus is very rarely affected. CASE PRESENTATION: A 28-year-old Arab woman presented with chronic chest pain and dyspnea. A computed tomography scan showed a huge anterior mediastinal mass invading neighboring structures. A mediastinotomy was performed with biopsies of the mass. Pathological findings were consistent with a thymic large cell neuroendocrine carcinoma. CONCLUSIONS: The occurrence of a large cell neuroendocrine carcinoma in the thymus, especially in young people, is extremely rare. In this current report, we discuss the clinicopathological issues of this rare tumor according to recent literature data.

Can p63 serve as a biomarker for giant cell tumor of bone? A Moroccan experience.

BACKGROUND: Multinucleated giant cell-containing tumors and pseudotumors of bone represent a heterogeneous group of benign and malignant lesions. Differential diagnosis can be challenging, particularly in instances of limited sampling. The purpose of this study was to evaluate the contribution of the P63 in the positive and differential diagnosis of giant cell tumor of bone. METHODS: This study includes 48 giant cell-containing tumors and pseudotumors of bone. P63 expression was evaluated by immunohistochemistry. Data analysis was performed using Epi-info software and SPSS software package (version 17). RESULTS: Immunohistochemical analysis showed a P63 nuclear expression in all giant cell tumors of bone, in 50% of osteoid osteomas, 40% of aneurysmal bone cysts, 37.5% of osteoblastomas, 33.3% of chondromyxoide fibromas, 25% of non ossifiant fibromas and 8.3% of osteosarcomas. Only one case of chondroblastoma was included in this series and expressed p63. No P63 immunoreactivity was detected in any of the cases of central giant cell granulomas or langerhans cells histiocytosis. The sensitivity and negative predictive value (NPV) of P63 immunohistochemistry for the diagnosis of giant cell tumor of bone were 100%. The specificity and positive predictive value (PPV) were 74.42% and 59.26% respectively. CONCLUSIONS: This study found not only that GCTOB expresses the P63 but it also shows that this protein may serve as a biomarker for the differential diagnosis between two morphologically similar lesions particularly in instances of limited sampling. Indeed, P63 expression seems to differentiate between giant cell tumor of bone and central giant cell granuloma since the latter does not express P63. Other benign and malignant giant cell-containing lesions express P63, decreasing its specificity as a diagnostic marker, but a strong staining was seen, except a case of chondroblastoma, only in giant cell tumor of bone. Clinical and radiological confrontation remains essential for an accurate diagnosis. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1838562590777252.

Low-grade fibromyxoid sarcoma arising in the big toe.

Low-grade fibromyxoid sarcoma (LGFMS) is a rare neoplasm commonly affecting young adults and typically arising in the somatic soft tissue of the proximal extremities. Its occurrence within the big toe is exceedingly rare. A 43-year-old man had surgery on a mass located in the big toe, which was first noted 6 months previously. Histological examination revealed LGFMS. One year after surgery, the patient is alive with no evidence of disease. Low-grade fibromyxoid sarcoma is a rare neoplasm that should be considered in the differential diagnosis of spindle cell neoplasms of the foot.

Anaplasic lymphoma kinase positive inflammatory myofibroblastic tumour with renal pelvic calculus: a case report.

Inflammatory myofibroblastic tumour is a distinctive mesenchymal neoplasm, composed of a variable admixture of myofibroblastic spindle-shaped and inflammatory cells which were originally described in the lung, as a nonneoplastic lesion and designated as an inflammatory pseudotumour. The lack of certainty of the IMTs pathogenesis is reflected in the large number of terms which have been attributed to this lesion. Recent genetic and molecular studies of IMTs have showed chromosomal abnormalities of 2p23 resulting in a rearrangement of the anaplasic lymphoma kinase gene and have also provided evidence for a monoclonal, noeplastic origin for IMT.Occurrence of IMT in the kidney is very rare, and to our knowledge, only 30 such cases have been described in the literature.This report describes an original case of an ALK positive IMT of the kidney associated with renal pelvic calculus which we believe has never been reported. The differential diagnosis of IMTs will also be discussed.