Rhabdomyosarcoma

This case report emphasizes the challenges in the diagnosis of RMS confined to the bone marrow due to its atypical presentation. It also highlights the poor prognosis and aggressiveness of this entity compared to conventional RMS.

These findings support L1CAM as a rational target for L1CAM-positive RMS cases and demonstrate that CAR optimization can enhance activity against moderate-density antigens. The potent antitumor activity and favorable selectivity profile of L1CAM.III-CAR T cells support their development for pediatric sarcoma immunotherapy.

The median time to progression was 7 months (range 2-16.5 months). The existence of a parallel relationship between the lesion and the ipsilateral inguinal region, as well as the vascular ball sign, is helpful in differentiating testicular ERMS from testicular seminoma.

Genetic testing of the rhabdomyosarcoma revealed a pathogenic c.4102dup (p.R1368fs) germline frameshift variant and a second c.5425G > A (p.G1809R) somatic missense variant in DICER1, as well as a somatic variant in BCOR. With this report, we advocate for further investigation of DICER1-associated rhabdomyosarcoma to improve management of this rare presentation.

Here, we describe two patients with EWSR1::PATZ1 sarcoma, of which one patient was initially misdiagnosed as synovial sarcoma and RMS on two occasions. These patients underscore the diagnostic challenges and therapeutic uncertainties surrounding EWSR1::PATZ1 fusion sarcomas, emphasizing the need for further large collaborative studies to establish optimal prognostic implications and management strategies for this rare entity.

P2/3, N=140, Completed, National Cancer Institute (NCI) | Active, not recruiting --> Completed | Trial completion date: Dec 2026 --> Mar 2026

A complete blood count obtained locally after return home showed severe cytopenias, prompting growth-factor support and close hematology-oncology follow-up. This case highlights that PPB should be prioritized in the differential diagnosis of aggressive pediatric intrathoracic masses with pneumothorax and mass effect, and demonstrates the value of adequate tissue sampling, expert pathology review, and early integration of molecular testing to prevent protocol misdirection and to trigger DICER1-directed genetic counseling and surveillance.

Histologic subtyping of unclassified sarcomas predicted prognosis and therapeutic response. We propose universal MMR IHC screening of (1) PRMS, (2) uterine LMS, (3) unclassified/UPS, and (4) any sarcoma in a patient with a personal or family history of Lynch syndrome.

In addition, we demonstrate that the first bromodomain of the bromodomain and extraterminal domain-containing protein BRD4 binds to the acetylated region of interest and that this interaction is inhibited through the bromodomain and extraterminal domain inhibitor JQ1. These findings confer molecular mechanistic detail to previous observations that BRD4 and PAX3-FOXO1 colocalize at superenhancers in ARMS, adding to the growing body of literature exploring how BRD4 contacts cancer-relevant transcription factors in ways potentially relevant to the use of bromodomain and extraterminal domain inhibitors in cancer treatment.

In conclusion, PATZ1 IHC is moderately sensitive and specific for PATZ1-rearranged sarcomas, and it may be a helpful diagnostic marker for this challenging tumor. While most tumors with morphologic overlap with PATZ1-rearranged sarcomas are negative for PATZ1 by IHC, expression in a subset of myoepithelial tumors and rhabdomyosarcomas represents a potential diagnostic pitfall.

PRAME is an antigen that has been described in primary cutaneous and metastatic melanomas and has become a useful ancillary immunohistochemical marker, particularly when all others are negative. We present a patient with metastatic melanoma to the left atrium with loss of melanocytic differentiation, gain of a rhabdomyosarcomatous differentiation, and a diffuse and strong positivity for PRAME.

This phenomenon was evidenced by the following indicators: reduced clone formation, increased cell apoptosis, cell cycle arrest, as well as the inhibition of tumor cell proliferation. Taken together, our study revealed that shepherdin not only modulates the biological behavior of RMS cells but also enhances their sensitivity to X-ray irradiation, demonstrating its potential as an effective therapeutic strategy for RMS.