RESUMO
Rhabdomyosarcoma with TFCP2 rearrangement is a recently identified malignant neoplasm characterized by immunohistochemical evidence of rhabdomyoblastic differentiation, keratin expression, upregulation of ALK, and an aggressive clinical course. This neoplasm has a tendency to affect craniofacial bones, with only a few reported cases of extra-osseous tumors. Here, we present a case of cutaneous rhabdomyosarcoma with FUS::TFCP2 fusion in a 35-year-old female. Notably, the tumor exhibited a pathologic spectrum, initially resembling sclerosing dermatitis at presentation but progressing into a high-grade malignant tumor within 8 months. The distinctive immunoprofile of this neoplasm highlights the importance of early molecular studies for diagnosis, even in the presence of low-grade cytomorphology. Early detection may offer an opportunity for timely resection before the tumor becomes unresectable.
Assuntos
Neoplasias Ósseas , Rabdomiossarcoma , Feminino , Humanos , Adulto , Detecção Precoce de Câncer , Fatores de Transcrição/metabolismo , Rabdomiossarcoma/diagnóstico , Rabdomiossarcoma/genética , Rabdomiossarcoma/química , Biomarcadores Tumorais/genética , Proteínas de Ligação a DNA , Proteína FUS de Ligação a RNA/metabolismoRESUMO
The WHO Classification of Tumors of Soft Tissue and Bone divides rhabdomyosarcoma (RMS) into alveolar, embryonal, pleomorphic, and spindle cell/sclerosing types. Advances in molecular diagnostics have allowed for further refinement of RMS classification including the identification of new subtypes. Very rare RMS with epithelioid and spindle cell morphology, female predominance, marked osseous predilection, ALK expression, EWSR1/FUS-TFCP2 gene fusions, and highly aggressive clinical behavior have recently been recognized with only 23 cases reported in the English language literature. Herein, we report two additional cases with detailed clinicopathologic description and molecular confirmation. In brief, two young women presented each with a primary bone tumor-one with a frontal bone tumor and another with an osseous pelvic tumor. Both tumors showed epithelioid to spindle cell morphology, ALK expression, and EWSR1/FUS-TFCP2 gene fusions. Both patients died of disease less than 17 months from diagnosis despite administration of multiple lines of aggressive treatment. In addition, we review the literature and discuss differential diagnostic and potential treatment considerations.