CD99 (CD99 Molecule)

Intracardiac Ewing-like sarcomas represent a diagnostically challenging and highly aggressive entity with a grave prognosis due to limited surgical resectability, hemodynamic compromise, and heightened susceptibility to treatment-related complications. This case highlights the narrow therapeutic window in patients with cardiac involvement and underscores the importance of multidisciplinary evaluation and careful administration of intensive therapy.

Diagnosis depends on histopathology and immunohistochemistry, particularly STAT6. Complete excision is usually curative, but long-term surveillance remains essential.

These findings led to the diagnosis of primary renal adenosarcoma. This case highlights the diagnostic challenge of distinguishing this rare tumor from more common renal malignancies and underscores the importance of imaging-pathologic correlation.

This case highlights the diagnostic difficulty and rapid progression of renal Ewing sarcoma. Accurate diagnosis relies on integrated imaging, histopathology, immunoprofiling, and molecular testing. Early recognition and multidisciplinary decision-making are essential for optimizing outcomes in this rare tumor entity.

Immunohistochemistry showed diffuse positivity for CD56, chromogranin A, synaptophysin, and insulinoma-associated protein 1; a Ki-67 index of about 20%; negativity for CD5, CD117 (c-KIT), p63 (TP63), CK5/6, and CD20; and the absence of TdT/CD99-positive immature T cells, supporting a diagnosis of thymic atypical carcinoid. This case highlights the complementary value of imprint cytology and an appropriate immunohistochemical panel, in addition to frozen sections, in avoiding misclassification of tNENs as type A thymoma.

Histopathology revealed a highly cellular neoplasm of uniform small round blue cells arranged in sheets and nests, immunoreactive for cluster of differentiation 99 (CD99) with diffuse membranous staining and negative for AE1/AE3, desmin, CD45, and S100. Targeted next-generation sequencing confirmed an EWSR1/FLI1 fusion, establishing the diagnosis of ES.

This case highlights the role of TPR::NTRK1 fusion in driving abnormal melanocyte proliferation and the potential contribution of MCL1 amplification to tumor progression. These findings provide insights into the genetic underpinnings of APN in CMN and suggest potential therapeutic targets for high-risk lesions.

Immunostain for androgen receptor was strongly and diffusely positive in the primary tumor and in the nodal metastasis, which together with focal staining for NKX3.1 were suggestive of primary prostatic origin and invited consideration of androgen deprivation therapy. This report highlights a rare prostatic Ewing-family sarcoma harboring an EWSR1::FEV fusion and immunophenotypic features that mimic a neuroendocrine carcinoma.

It also underscores the critical role of immunohistochemistry, particularly STAT6 staining, in distinguishing SFT from histologic mimics. Vigilant follow-up remains essential, especially in atypical or CD34-negative cases, given their potential for aggressive behavior.

However, the short follow-up duration likely underestimates true long-term recurrence rates in adult-type GCTs, which characteristically recur late. Small sample size (particularly juvenile cohort, n=3), single-center design, relatively short follow-up (median 60 months; 72% <8 years), and absence of GCT-specific tumor markers (Inhibin B, AMH) limit generalizability and assessment of long-term outcomes.

In a Ewing sarcoma xenograft model, wave bioreactor-cultured CAR-T cells showed a greater percentage of memory-like tumor-infiltrating lymphocytes. Collectively, these results indicate that wave bioreactor-based dynamic cultivation promotes mitochondrial metabolic reprogramming, which is characterized by an enhanced TCA cycle and sustained oxidative phosphorylation, thereby sustaining CAR-T cell functionality and providing a robust platform for the manufacturing of potent and durable cellular therapeutics.

This study identified CDKN2A and MMP14 as potential OS biomarkers and elucidated their role within the stromal cell network, suggesting resveratrol as a candidate therapeutic molecule targeting MMP14. The present discoveries provided new insights for understanding the progression mechanisms and developing precise diagnosis and treatment strategies for OS.