Heart transplantation is undergoing a continuous development, with rates of success increasing substantially due to advances in immunosuppressive therapy and surgical techniques. The most worrying complication occurring after cardiac transplantation is graft rejection, a phenomenon that is much affected by matrix metalloproteinases (MMPs), with the role of these proteases in the cardiac remodeling process being well established in the literature. A detailed investigation of the association between MMPs and cardiac rejection is necessary for the future development of more targeted therapies in transplanted patients, and to discover prognostic serum and immunohistochemical markers that will lead to more organized therapeutic management in these patients. The aim of this review is therefore to highlight the main MMPs relevant to cardiovascular pathology, with particular emphasis on those involved in complications related to heart transplantation, including cardiac graft rejection.

Introduction: Endometrial endometrioid carcinomas can show multiple lines of differentiation, including pilomatrix-like high-grade endometrioid carcinoma, a recently described tumor with similarity to cutaneous pilomatrix carcinoma and associated with very aggressive clinical behavior. Methods: We present a 56-year-old woman with an endometrial tumor associated with secondary involvement of both ovaries, left tubo-ovarian ligament and obturator lymph nodes. The diagnosis of high-grade endometrioid carcinoma in a previously performed curettage was confirmed in the hysterectomy specimen. Results: Microscopically, the tumor exhibited a solid, nested/insular pattern with basaloid cells, predominantly seen at the periphery, ghost cell keratinization towards the center of the nests, and extensive geographic necrosis. No low-grade endometrioid carcinoma component was identified throughout the primary tumor or metastases after extensive sampling. Immunohistochemical assessment showed aberrant cytoplasmic and nuclear expression of β-catenin, and focal CDX2 expression. Tumor cells were negative for PAX8, and estrogen and progesterone receptors (ER/PR). The next-generation sequencing (NGS) analysis found a CTNNB1 pathogenic mutation (p.Ser37Phe, c.110C > T; variant allele frequency: 18.6%). Based on these morphologic, immunohistochemistry and NGS analysis, a diagnosis of pilomatrix-like high-grade endometrioid carcinoma was established. Conclusion: The absence of a low-grade endometrioid carcinoma component makes this pilomatrix-like high-grade endometrioid carcinoma, a very rare tumor, even more special. This and the absence of PAX8 and ER/PR expression in an unusual morphological context proved to be diagnostically challenging. This patient's presentation at high stage is concordant with the literature's description of this tumor as aggressive. It is not yet known whether standard adjuvant therapies for high-risk endometrial carcinomas are effective.

Uterine smooth muscle tumors (USMTs) represent a diagnostically and clinically challenging subset of uterine mesenchymal neoplasms. Up to 5% of these tumors exhibit ambiguous histological features that preclude definitive classification as either benign leiomyomas or malignant leiomyosarcomas. This review provides a comprehensive synthesis of the evolving diagnostic criteria, histopathological variants, and recent advancements in immunohistochemical and molecular profiling of smooth muscle tumors with uncertain malignant potential (STUMPs). The review traces the historical development of diagnostic criteria, from the original mitotic thresholds to the “Stanford criteria,” which incorporate mitotic index, cytological atypia, and tumor cell necrosis. Contemporary WHO guidelines largely uphold these principles, with nuanced refinements for spindle, myxoid, and epithelioid subtypes. However, recent studies suggest additional morphologic indicators, such as atypical mitoses, infiltrative margins, and vascular invasion, may provide prognostic insight. Notably, necrosis remains the most reliable histologic predictor of recurrence, while mitotic activity and atypia, though important, are less specific. In conclusion, STUMPs represent a heterogeneous group with unpredictable behavior that requires long-term clinical follow-up. While existing histological and molecular tools aid classification, definitive prognostic markers remain elusive. Further studies integrating histopathology, immunohistochemistry, and molecular biology are essential to refine diagnosis and improve therapeutic decision-making in this diagnostically ambiguous group of uterine tumors.

Valvular hemangiomas are uncommon vascular anomalies that appear on the surface of heart valves. They can cause an array of non-specific symptoms and are consequently rarely diagnosed, with only 31 such cases (including the present one) reported to date in the literature; the present case is the first report of an arteriovenous hemangioma with a tricuspid localization. During the preoperative echocardiographic examination for a ventricular septal defect, a mass was incidentally discovered on the tricuspid valve of a 9-month-old infant. The involved leaflet was surgically removed and sent to the pathology department for analysis and subsequently diagnosed as an arteriovenous hemangioma. The patient recovered well, with no local tumor recurrence or other complications. The microscopic examination showed multiple blood vessels which stained positive for the endothelial markers CD31 and CD34 and which did not express D2-40, normally found in lymphatic endothelia. Surprisingly, endothelial cells lining the vessels also showed positivity for SMA, a mesenchymal cell marker, indicating a possible involvement of endothelial-to-mesenchymal transition and its opposite process, mesenchymal-to-endothelial transition, in the pathogenesis of these vascular anomalies.