Phenotypic characterization of perivascular myoid cell neoplasms, using myosin 1B, a newly identified human pericyte marker

Integrated analysis of canine soft tissue sarcomas identifies recurrent mutations in TP53, KMT genes and PDGFB fusions

Soft tissue sarcomas (STS) are a heterogenous group of mesenchymal tumors representing over 50 distinct types with overlapping histological features and non-specific anatomical locations. Currently, localized sarcomas are treated with surgery + / -  radiation in both humans and dogs with few molecularly targeted therapeutic options. However, to improve precision-based cancer therapy through trials in pet dogs with naturally occurring STS tumors, knowledge of genomic profiling and molecular drivers in both species is essential. To this purpose, we sought to characterize the transcriptomic and genomic mutation profiles of canine STS subtypes (fibrosarcoma, undifferentiated pleomorphic sarcoma, and peripheral nerve sheath tumors), by leveraging RNAseq, whole exome sequencing, immunohistochemistry, and drug assays. The most common driver mutations were in cell cycle/DNA repair (31%, TP53-21%) and chromatin organization/binding (41%, KMT2D-21%) genes. Similar to a subset of human sarcomas, we identified fusion transcripts of platelet derived growth factor B and collagen genes that predict sensitivity to PDGFR inhibitors. Transcriptomic profiling grouped these canine STS tumors into 4 clusters, one PNST group (H1), and 3 FSA groups selectively enriched for extracellular matrix interactions and PDFGB fusions (H2), homeobox transcription factors (H3), and elevated T-cell infiltration (H4). This multi-omics approach provides insights into canine STS sub-types at a molecular level for comparison to their human counterparts, to improve diagnosis, and may provide additional targets for chemo- and immuno-therapy.

Glomus Tumor of Sella Turcica With Synaptophysin Expression Mimicking Pituitary Adenoma

Glomus tumor can rarely arise in the central nervous system as a sella turcica mass. In this article, we report a case of sellar glomus tumor in a female patient who presented at the age of 8 years with visual impairment. The tumor recurred at 4 years and 26 years after initial excision and gamma knife therapy. Histologic examination showed a monotonous population of oval cells accompanied by delicate blood vessels, features mimicking pituitary adenoma. The tumor showed histologic progression at the second recurrence. Synaptophysin staining was positive, but chromogranin and CD56 were negative. The tumor cells were negative for epithelial markers but expressed actin and SMA. Awareness of the rare occurrence of glomus tumor at this region, careful analysis of morphology, and appropriate immunohistochemical workup are essential to solve this diagnostic challenge. The clinicopathologic features of all previously reported cases are reviewed.

Mesenchymal Neoplasms of the Genitourinary System: A Selected Review with Recent Advances in Clinical, Diagnostic, and Molecular Findings

Mesenchymal neoplasms of the genitourinary (GU) tract often pose considerable diagnostic challenges due to their wide morphologic spectrum, relative rarity, and unexpected incidence at GU sites. Soft tissue tumors arise throughout the GU tract, whether from adventitia surrounding or connective tissues within the kidneys, urinary bladder, and male and female genital organs. This selected article focuses on a subset of these lesions, ranging from benign to malignant and encompassing a range of patterns of mesenchymal differentiation, where recent scholarship has lent greater insight into their clinical, molecular, or diagnostic features.