Embryonal rhabdomyosarcoma in the maxillary sinus with orbital involvement in a pediatric patient: Case report

Orbital Rhabdomyosarcoma Masquerading as a Dermoid Cyst: A Case Report and Review of the Literature

The purpose of this report is to present a case of orbital rhabdomyosarcoma (RMS) masquerading as a dermoid cyst. A six-year-old boy with an unremarkable medical history presented in the outpatient department with a palpable mass in the superonasal region of the right orbit, which had rapidly grown in the past month. The most likely diagnosis was dermoid cyst and the patient was scheduled for surgical excision. A high index of suspicion was raised intraoperatively based on the appearance of the lesion due to the presence of a feeder vessel. The histopathology examination identified alveolar RMS. The patient was referred to a pediatric oncology department and commenced intravenous chemotherapy. RMS may masquerade as various conditions, including dermoid cysts and chalazion. A high index of suspicion should be raised in cases with rapidly growing lesions.

Pediatric Sinonasal Rhabdomyosarcoma Presented as Squint: A Case Report and Literature Review

Rhabdomyosarcoma (RMS) is the most common soft-tissue tumor in children, frequently affecting the nose, nasopharynx, and paranasal sinuses. RMS of this sinonasal region manifests with non-specific nasal symptoms of allergic rhinitis, sinusitis, or upper airway infection. Associated ocular symptoms are rare. We describe a young girl who presented with acute onset squint secondary to sinonasal RMS. Imaging showed an aggressive sinonasal tumor with oropharyngeal, intraorbital, and intracranial extension. Histopathological findings were consistent with a diagnosis of rhabdomyosarcoma, embryonal type. The patient deteriorated rapidly due to disease complications. We provide a literature review of pediatric sinonasal RMS with various manifestations.

MRI of Sinonasal Malignancies

ABSTRACT

Sinonasal cavity is an important subsite in head and neck tumors. There are a myriad of malignancies that present within this area. Adequate staging for treatment planning requires multimodality evaluation. Magnetic resonance imaging (MRI) forms an important component in the evaluation of sinonasal tumors. We sought to review the most common sinonasal tumors, including sinonasal anatomy, clinical features, and common imaging features. A literature review was performed to evaluate common sinonasal tumors. Owing to the different tissue types within the sinonasal cavity, there are multiple different tumor pathologies within the sinonasal compartment. Most present in adults although some present in the young. Many of these tumor types have imaging overlaps, although some have a characteristic appearance. MRI can aid in soft tissue delineation, evaluation of multicompartmental extension, intracranial spread, and perineural spread. Sinonasal tumors are a heterogeneous group for which soft tissue delineation via MRI forms an important role in ensuring adequate treatment planning to improve outcomes, decreasing morbidity, and improve functional outcomes.

Expanding the Spectrum of Intraosseous Rhabdomyosarcoma: Correlation Between 2 Distinct Gene Fusions and Phenotype

Primary intraosseous rhabdomyosarcomas (RMSs) are extremely rare. Recently 2 studies reported 4 cases of primary intraosseous RMS with EWSR1/FUS-TFCP2 gene fusions, associated with somewhat conflicting histologic features, ranging from spindle to epithelioid. In this study we sought to further investigate the pathologic and molecular abnormalities of a larger group of intraosseous RMSs by a combined approach using targeted RNA sequencing analysis and fluorescence in situ hybridization (FISH). We identified 7 cases, 3 males and 4 females, all in young adults, age range 20 to 39 years (median, 27 y). Three cases involved the pelvis, 2 involved the femur and 1 each involved the maxilla and the skull. Molecular studies identified recurrent gene fusions in all 7 cases tested, including: a novel MEIS1-NCOA2 fusion in 2 cases, EWSR1-TFCP2 in 3 cases, and FUS-TFCP2 gene fusions in 1 case. One case showed a FUS gene rearrangement, without a TFCP2 gene abnormality by FISH. The MEIS1-NCOA2-positive cases were characterized by a more primitive and fascicular spindle cell appearance, while the EWSR1/FUS rearranged tumors had a hybrid spindle and epithelioid phenotype, with more abundant eosinophilic cytoplasm and mild nuclear pleomorphism. Immunohistochemically, all tumors were positive for desmin and myogenin (focal). In addition, 4 tumors with TFCP2-associated gene fusions also coexpressed ALK and cytokeratin. In conclusion, our results suggest a high incidence of gene fusions in primary RMSs of bone, with 2 molecular subsets emerging, defined by either MEIS1-NCOA2 or EWSR1/FUS-TFCP2 fusions, showing distinct morphology and immunophenotype. Additional studies with larger numbers of cases and longer follow-up data are required to definitively evaluate the biological behavior of these tumors and to establish their relationship to other spindle cell RMS genetic groups.