Spindle Cell Sarcoma

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.

RAF/BRAF-driven mesenchymal tumours possess a broader clinicopathologic spectrum than traditionally recognised, frequently affecting adults and deep/visceral sites. Their inherently variable immunophenotypes and the presence of high-grade morphologic features do not strictly predict an aggressive clinical trajectory. Comprehensive molecular profiling is essential to refine diagnostic criteria, accurately identify these neoplasms, and elucidate the genomic events associated with tumour progression.

P2, N=798, Active, not recruiting, National Cancer Institute (NCI) | Trial primary completion date: May 2027 --> May 2026

Adult-onset ALK-positive IMT with extensive pulmonary involvement and multiorgan metastases is exceedingly rare. This case highlights the diagnostic challenges posed by sarcomatoid morphology and underscores the importance of integrating histopathology, immunohistochemistry, and clinical correlation, with ALK testing providing both diagnostic confirmation and a potential therapeutic target.

On follow-up PET-CT scan after imatinib therapy, the patient showed a complete/near complete metabolic response. This report expands the imaging spectrum of PHGIST and emphasizes the importance of radiologic-pathologic correlation in distinguishing this rare lesion from metastatic liver disease.

Despite treatment with pembrolizumab, the disease progressed rapidly both locally and distantly, necessitating palliative care. This case highlights the persistent challenges in diagnosing oral mucosal melanoma due to its atypical clinical and pathological features, emphasizes the critical role of immunohistochemistry in achieving an accurate diagnosis, and underscores the generally poor prognosis despite current therapeutic options. It also reinforces the importance of early detection and timely multidisciplinary management.

Our results support the incorporation of ALK immunohistochemistry as a screening tool and demonstrate the utility of anchored multiplex PCR-based RNA sequencing for the detection of therapeutically relevant fusions, particularly those with uncommon partners. This integrated approach may refine the diagnosis and support consideration of ALK-directed therapy in these rare tumors.

Perineurioma-like, EMA-positive calvarial neoplasms are a rare group of spindle cell tumours for which no local recurrence or distant metastasis has been documented to date, although they do show a propensity for progressive growth. Recognition of their distinctive clinicopathological and radiological features is important for accurate diagnostic classification and appropriate patient management.