Inflammatory myofibroblastic tumour of the rectum with a novel anaplastic lymphoma kinase fusion diagnosed on cytology: Not just another submucosal gastrointestinal stromal tumour!

Inflammatory myofibroblastic tumours (IMT) are spindle cell neoplasms most commonly seen in the lungs, with a wide variety of less common extrapulmonary sites including the mesentery, omentum, and intrabdominal sites. On cytological evaluation, these tumours can be difficult to diagnose, given the morphological mimics of other submucosal spindle cell neoplasms, which may be compounded by the relatively small amount of tissue and the uncommon nature of the diagnosis. Immunohistochemical staining and molecular studies for the ALK gene can prove useful for diagnosing this tumour. We present the cytological features of an IMT occurring in the rectum, the differential diagnoses, useful immunohistochemical staining patterns, and the additional finding of a novel ALK-fusion in this entity.

Recommended testing algorithms for NTRK gene fusions in pediatric and selected adult cancers: Consensus of a Singapore Task Force.

The occurrence of neurotrophic tyrosine receptor kinase (NTRK) gene fusions in a wide range of tumor types presents an attractive opportunity for using a tropomyosin receptor kinase (TRK) inhibitor as cancer therapy. Recent clinical studies have demonstrated highly efficacious outcomes associated with the use of TRK inhibitors, such as larotrectinib and entrectinib in NTRK fusion-bearing cancers, in both adult and pediatric populations. While NTRK gene fusions are commonly found in some uncommon adult and pediatric malignancies, they are also found, albeit rarely, in a wide range of more common malignancies. The potential value of testing for NTRK gene fusions in practically all advanced malignancies is underpinned by the remarkable therapeutic outcomes that TRK inhibitors offer. This requirement presents practical and financial challenges in real-world oncological practice. Furthermore, different testing platforms exist to detect NTRK gene fusions, each with its advantages and disadvantages. It is, therefore, imperative to develop strategies for NTRK gene fusion testing in an attempt to optimize the use of limited tissue specimen and financial resources, and to minimize the turnaround time. A multidisciplinary task force of Singapore medical experts in both public and private sectors was convened in late 2020 to propose testing algorithms for adult colorectal tumors, sarcomas, non-small cell lung cancer, and pediatric cancers, with particular adaptation to the Singapore oncological practice. The recommendations presented here highlight the heterogeneity of NTRK-fusion positive cancers, and emphasize the need to customize the testing methods to each tumor type to optimize the workflow.

Genomic and Transcriptomic Profiling of Combined Hepatocellular and Intrahepatic Cholangiocarcinoma Reveals Distinct Molecular Subtypes.

We performed genomic and transcriptomic sequencing of 133 combined hepatocellular and intrahepatic cholangiocarcinoma (cHCC-ICC) cases, including separate, combined, and mixed subtypes. Integrative comparison of cHCC-ICC with hepatocellular carcinoma and intrahepatic cholangiocarcinoma revealed that combined and mixed type cHCC-ICCs are distinct subtypes with different clinical and molecular features. Integrating laser microdissection, cancer cell fraction analysis, and single nucleus sequencing, we revealed both mono- and multiclonal origins in the separate type cHCC-ICCs, whereas combined and mixed type cHCC-ICCs were all monoclonal origin. Notably, cHCC-ICCs showed significantly higher expression of Nestin, suggesting Nestin may serve as a biomarker for diagnosing cHCC-ICC. Our results provide important biological and clinical insights into cHCC-ICC.

Follicular dendritic cell sarcoma of the liver with metachronous small bowel and splenic metastases: a case report and literature review.

Follicular dendritic cell sarcoma (FDCS) of the liver is an extremely rare disease, accounting for a mere 0.4% of all soft tissue sarcomas. FDCS most commonly involves lymph nodes but also affects extranodal sites such as the gastrointestinal system, oral cavity, liver, spleen and pancreas, albeit less commonly. It is widely considered a low-to-intermediate grade malignancy. We report a case of FDCS with metachronous involvement of the liver, small intestines and spleen, its imaging, histological findings and its management.

Toxic haemorrhagic colitis: a rare presentation of eosinophilic colitis.

Eosinophilic colitis is a rare condition that usually presents with non specific abdominal symptoms. Very uncommonly it presents with an acute surgical emergency such as peritonitis or haemorrhage. We present a rare presentation of eosinophilic colitis with toxic hemorrhagic colitis and ischaemic bowel requiring laparotomy and bowel resection.