Pediatric fibromyxoid brachial plexus tumor with YWHAZ::PLAG1 gene fusion: a case report.

Pediatric fibromyxoid soft tissue tumors may be associated with gene fusions such as YHWAZ::PLAG1, with only three reported cases in the literature. We present the fourth case, a 13-year-old male with a pediatric fibromyxoid brachial plexus tumor with YWHAZ::PLAG1 gene fusion. This is also the first case to be reported in an adolescent, in the brachial plexus, and in the Philippines. The patient presented with a 10-year history of a slowly growing left supraclavicular mass and a 1-year history of intermittent dysesthesia in the left upper extremity. Neurologic examination was unremarkable. Imaging revealed a large left supraclavicular lesion with intrathoracic extension. Surgical excision was performed, and histopathology revealed a fibromyxoid tumor with YWHAZ::PLAG1 gene fusion. Although previous examples of this gene fusion pointed toward lipoblastoma as their primary pathology, our tumor does not completely fulfill the current diagnostic criteria for a lipoblastoma and may represent an intermediate form of the disease. Our case is unique not only because it is the first reported adolescent patient harboring such a lesion but also because of the relatively lengthy natural history exhibited by the tumor prior to its resection. This provided us with valuable information about its behavior, which suggests a more indolent growth pattern. This case also highlights the clinical importance of molecular testing of tumors, where recognition of disease entities can assist clinicians in deciding and advocating for the proper management.

Unplanned Excision of Soft Tissue Sarcomas of the Extremities in a Low-to-Middle-Income Country.

BACKGROUND: Outcomes of unplanned excisions of extremity soft tissue sarcomas (STSE) range from poor to even superior compared with planned excisions in developed countries. However, little is known regarding outcomes in low-to-middle-income countries. This study aimed to determine whether definitively treated STSE patients with a previous unplanned excision have poorer oncologic outcomes compared with those with planned excisions. PATIENTS AND METHODS: Using the database of a single sarcoma practice, we reviewed 148 patients with STSE managed with definitive surgery-78 with previous unplanned excisions (UE) and 70 with planned excisions (PE). RESULTS: Median follow-up was 4.4 years. UE patients had more surgeries overall and plastic reconstructions (P < 0.001). On multivariate analysis, overall survival (OS), local recurrence-free survival (LRFS), and distant metastasis-free survival (DMFS) were not worse among UE patients compared with PE patients. Negative predictors for LRFS were high tumor grade (P = 0.031) and an R1 surgical margin (P < 0.001). High grade (P <0.001), local recurrence (P = 0.001), and planned excisions (P = 0.009) predicted poorer DMFS, while age over 65 years (P = 0.011) and distant metastasis predicted poorer OS (P < 0.001). CONCLUSIONS: We recommend systematic re-excision for patients with unplanned excisions. Our study shows that STSE patients with UE, when subjected to re-excision with appropriate surgical margins, can achieve oncologic results similar to those for PE patients. However, there is an associated increased number of surgeries and plastic reconstruction for UE patients. This underscores the need, especially in a resource-limited setting, for education and collaborative policies to raise awareness about STSE among patients and physicians.

YJ5 as an immunohistochemical marker of osteogenic lineage.

Overexpression of WLS, an upstream protein in the Wnt pathway, has been implicated in several non-osteogenic tumours. This study represents the first attempt at evaluating WLS expression in various bone and soft tissue tumours using YJ5, a monoclonal antibody specific to WLS, with the aim of elucidating its utility in discerning tumours with aberrant Wnt signalling and as a marker of osteogenic lineage in challenging cases. Tumour tissue sections of 144 bone mass lesions and 63 soft tissue mass lesions were immunostained with the YJ5 antibody following standardised protocols. Subsequent assessment of immunoreactivity segregated cases into one of three groups: absent/weak, moderate, or strong YJ5 immunoreactivity. For the bone tumours, strong YJ5 immunoreactivity was seen in almost all osteosarcomas and chondroblastomas, all osteoblastomas and osteoid osteomas. In contrast, all other cartilaginous tumours, chordomas, aneurysmal bone cysts, chondromyxoid fibromas, most fibrous dysplasias and most giant cell tumours exhibited absent/weak YJ5 immunostaining. For the soft tissue tumours, a more heterogeneous pattern of YJ5 immunoreactivity was observed. Because diffuse and strong YJ5 expression is identified in almost all benign and malignant bone tumours with osteoblastic activity, it can be potentially utilised as an immunohistochemical marker to support osteogenic lineage. If interpreted in the appropriate context, this marker is useful in determining whether a malignant bone tumour is an osteosarcoma, particularly in those subtypes with no or minimal osteoid or unusual morphological features. This marker can also complement SATB2 to denote osteogenic lineage.