Correlation between KRAS and NRAS mutational status and clinicopathological features in 414 cases of metastatic colorectal cancer in Morocco: the largest North African case series.

BACKGROUND: Advances in molecular biology have improved understanding of the molecular features of carcinogenesis and progression of colorectal cancer. It is clear that the efficacy of anti-EGFR depends upon the RAS mutational status, since any mutation in RAS is associated with resistance to anti-EGFR therapy. The aim of this study is to report the largest North African description of KRAS and NRAS status in metastatic colorectal cancer and to describe the association of these mutations with clinicopathological characteristics. METHODS: This is a prospective study of all consecutive unselected metastatic colorectal cancer samples, collected from the Laboratory of Pathology at the National Institute of Oncology of Rabat, Morocco, from January 1st 2020 to December 31st 2021. The molecular analysis was performed on the Idylla™ platform (fully automated real-time polymerase chain reaction-based assay) for KRAS and NRAS mutations in exons 2, 3 and 4. These mutations were correlated to gender, primary tumor site, histological type and degree of differentiation of tumor using adequate statistical methods. RESULTS: Four hundred fourteen colorectal tumors were screened for KRAS and NRAS mutations. These mutations occurred in 51.7% of tumors for KRAS (mainly in exon 12) and in 3% of tumors for NRAS. There was a significant correlation between NRAS mutation and age of colorectal patients in this study. The low rate of invalid RAS tests (1.7% for KRAS and 3.1% for NRAS) was certainly obtained due to the strict respect of pre-analytical factors such as cold ischemia time and formalin fixation. CONCLUSION: We report the largest North African analysis of NRAS and KRAS status in colorectal metastatic patients. This study showed the ability in low middle income countries to perform a high rate of valid tests and the unusual trend towards older patients for NRAS mutations.

An unusual variant of lipoma: case report.

Osteo-lipoma is a very rare benign tumor with a good prognosis. It is composed mainly of mature fatty tissue with a bony component. The diagnosis is based on the histological study, given the clinical and radiological characters that can simulate other benign or malignant pathologies. Osteosarcoma is the main differential diagnosis. The distinction between these two neoplasms is essential as the basis of the treatment is different. We report the case of a patient with a giant ossifying lipoma independent of bone tissue located in the thigh.

Breast metastasis 18 years after nephrectomy for renal cell carcinoma: a case report.

Metastasis of renal clear cell carcinoma (RCC) to the breast is exceptional. Breast metastases of extra-mammary tumors are rare and usually involve melanoma, lymphoma or leukemia. We report the case of a patient with breast metastasis of renal clear cell carcinoma occurring 18 years after nephrectomy. A history of RCC should always raise suspicion about breast metastasis, a situation that remains exceptional and whose diagnosis relies on anatomopathology.

Adenoid Cystic Carcinoma of the Uterine Cervix: A Report of 2 Cases.

Adenoid cystic carcinoma is malignant tumor that exceptionally occurs in the uterine cervix. It is mostly seen in postmenopausal women and has an aggressive clinical course. We report two cases of an adenoid cystic carcinoma associated with a high grade squamous intraepithelial lesion and invasive squamous cell carcinoma of the uterine cervix and discuss briefly its clinical and pathological characteristics.

[Giant cell tumor of soft tissues. Report of two cases]. / Tumeur à cellules géantes des tissus mous.

We report two cases of giant-cell tumour of soft tissue (TCG-TM). The first case occurred in a 26-year-old woman presenting with a subcutaneous tumour of the left leg. Pathological study revealed a tumour comparable to benign giant cell tumour of bone. The patient is well without recurrence 10 months after the diagnosis. The second case concerned a 49-year-old man with a huge mass of the thigh. Microscopically, the tumour was composed of sheets of mononuclear and multinucleated cells. Mononuclear cells presented severe atypia and a high mitotic activity. Eighteen months later, the patient died with diffuse pulmonary metastases. TCG-TMs are uncommon and represent a distinct entity whose clinical behaviour and histological features are similar to giant-cell tumour of bone. The malignant variant is debatable. The differential diagnosis includes other tumours rich in osteoclast-like cells.