Vol 7, No 4 (2024)

Therapy choice for colorectal cancer is currently quite extensive and depends on molecular subtype of the tumor, since it has a high level of intertumor molecular heterogeneity. Microsatellite instability (MSI) is one of the important predictors of response to checkpoint inhibitors of immune response. At the moment, the defects in the unpaired base repair system (dMMR) and MSI are recognized using 2 methods: immunohistochemical and polymerase chain reaction. The present work investigated the concordance between these methods in a large sample of patients with colorectal cancer and assessed the reasons for discrepancies in the results.

Atypical polypoid adenomyoma is a rare tumor of the endometrium, which occurs mainly in women of reproductive age. Despite the fact that it belongs to benign neoplasms, it is distinguished by the possibility of recurrence and progression to endometrial adenocarcinoma, as well as a possible coexistence with atypical hyperplasia and endometrial adenocarcinoma, leading to significant difficulties in the differential diagnosis of this lesion and imposes special responsibility on the pathologist related to the possibility of conservative therapy. Nevertheless, there are a number of morphological and immunohistochemical characteristics that are presented in this article helping to make the correct diagnosis in such cases.

Uterine inflammatory myofibroblastic tumor represents a rare neoplasm characterized by a diverse range of morphological features and immunohistochemical profiles. Most of these tumors have a favorable prognosis, however, a subset exhibits aggressive behavior, with a tendency to recur and metastasize. The expression of smooth muscle markers can complicate the differential diagnosis with other smooth muscle tumors, such as smooth muscle tumors of uncertain malignant potential and leiomyosarcoma. ALK expression is a significant diagnostic marker, however, a subset of ALK-negative inflammatory myofibroblastic tumors may remain unrecognized. This case highlights the challenges of morphological diagnosis of inflammatory myofibroblastic tumors with a predominant spindle cell pattern and a mild inflammatory infiltrate. Accurate diagnosis is crucial for selecting the optimal treatment strategy, as patients with an aggressive variant of the disease may benefit from targeted therapy with tyrosine kinase inhibitors.

Intimal sarcoma is a very rare malignant mesenchymal tumor that arises in the large blood vessels of the systemic and pulmonary circulation, as well as in the heart. The prognosis of intimal sarcoma is usually unfavorable and is strongly influenced by the choice of treatment strategy in favor of surgical intervention. The article presents an analysis of two clinical cases of intimal sarcoma of the heart, literature review, discussion of possible errors in the diagnosis of this rare disease.