Spindle Cell Sarcoma

These findings suggest that HLA class I downregulation may contribute to ICI resistance.

This case highlights the metastatic potential of ALK-rearranged unclassified mesenchymal neoplasms, particularly those exhibiting a tyrosine kinase phenotype (co-expression of S100 and CD34), supporting their classification within the intermediate, rarely metastasizing category according to soft tissue tumor stratification principles. It further emphasizes the need for heightened clinical vigilance and thorough surgical management, which may influence long-term outcomes.

Sensory symptoms improved after surgery, and no recurrence was detected on magnetic resonance imaging at 18-month follow-up. This short-term outcome is encouraging, but long-term radiological surveillance remains necessary.

Complete surgical resection remains the treatment of choice and typically results in rapid metabolic resolution. As the role of adjuvant therapy is not yet well established, accurate histopathological evaluation, appropriate risk stratification, and long-term surveillance are crucial to optimize outcomes and detect recurrence early.

Primary breast leiomyosarcoma is a rare entity that remains diagnostically challenging. Immunohistochemistry is essential for accurate diagnosis, and optimal management requires a dedicated multidisciplinary approach.

Accurate diagnosis requires histopathological evaluation with EBV confirmation. Management remains challenging and often centers on local tumor control and immune reconstitution.

This case illustrates the compounding diagnostic pitfalls of oral IMT: dual-site involvement, two failed biopsies, ALK negativity in an elderly patient, and focal cytokeratin positivity risking misclassification as spindle cell carcinoma. Awareness of IMT histologic subtypes, meticulous tissue sampling, and systematic immunohistochemical profiling are essential to avoid misdiagnosis and unnecessary aggressive oncologic treatment.

No disease progression was observed at 9 months. This case demonstrates the potential efficacy of combination immunotherapy in aggressive metastatic MTSCC.

Continuous genomic monitoring is essential for identifying resistance mechanisms and guiding precision therapy. Future studies should explore the impact of different fusion partners on tumor behavior and therapeutic response.

Immunohistochemistry confirmed positivity for smooth muscle actin and vimentin with a Ki-67 index of 15%-20%, consistent with myopericytoma. The short-interval recurrence, invasive features, and high mitotic activity raised concern for malignant myopericytoma.ConclusionThis being only the second reported breast myopericytoma case report, highlights the diagnostic difficulty and emphasizes the importance of thorough pathologic and immunophenotypic assessment to distinguish it from more common spindle cell tumours of the breast and to guide appropriate surgical management.