Spindle Cell Sarcoma

M-AME encompasses heterogeneous patterns that overlap with the infiltrative-like pattern of classic AME (adenomyoepithelial adenosis form of tubular AME) and metaplastic breast carcinoma. Recognition of the underlying AME architecture, coupled with immunohistochemical and molecular correlation, supports pragmatic classification into in situ or invasive M-AME or conventional breast carcinoma arising in the context of AME. Together with clinical, radiological, and molecular correlations, this approach can help guide appropriate management.

Most LGSCL-B can be classified on CNB, but approximately one-fifth yield indeterminate results. Diagnostic challenges include overlapping morphological features, immunohistochemical profiles and potential reclassification at resection. Awareness of these pitfalls, along with selective use of adjunct molecular testing, may enhance diagnostic accuracy and reduce overtreatment.

The postoperative course was uneventful, with no recurrence on follow-up. This case highlights ileal perineurioma as a rare but important differential diagnosis in adult small-bowel intussusception, with definitive diagnosis reliant on histopathological and immunohistochemical evaluation.

Spindle cell fibromatosis of the breast (SCFB) is a rare benign tumor that closely mimics malignancy on imaging and clinical examination. Accurate diagnosis relies on histopathology and immunohistochemistry, particularly β-catenin staining, to guide appropriate management and avoid overtreatment while addressing its locally aggressive behavior and associated conditions.

This case highlights that pancreatic metastasis from intracranial SFT/HPC, although extremely rare, may occur after a prolonged latency period and mimic a hypervascular primary pancreatic neoplasm. In patients with a history of intracranial SFT/HPC, late metastatic disease should be considered, and definitive diagnosis relies on histopathological examination and targeted immunohistochemistry.

Immunohistochemical analysis showed diffuse positivity for cluster of differentiation 34 (CD34). These findings supported the diagnosis of paratesticular SFT.

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.