Congenital Spindle-Cell Rhabdomyosarcoma with TEAD1-NCOA2 Fusion: Case Report and Review of the Literature

Background: Spindle-cell and sclerosing rhabdomyosarcomas (ssRMSs) are recently described as a rare variant of rhabdomyosarcoma (RMS), categorized by the World Health Organization classification as a entity distinct from embryonal or alveolar RMSs. Recent studies have shown ssRMSs to be a group of entities with significant morphological overlap but with a great molecular heterogeneity, with some genetic alterations potentially offering a better prognosis. Tumors harboring MYOD1 (p.L122R) mutations usually occur in older children and have a poorer prognosis, while tumors with genetic translocations resulting in fusion genes involving NCOA2 and/or VGLL2 tend to be congenital. Reports in the literature mainly suggest a favorable prognosis for this subset; however, four cases of patients who experienced local progression and distant metastases have recently been described. Outcomes and best treatment options for this subset of patients are therefore not fully established. Methods: We reviewed the current literature about treatment and outcomes of ssRMSs in infants using the PubMed CENTRAL databases, including in our literature search papers published in English in the last ten years. Results: We present a very rare case of a 15-month-old female diagnosed with a spindle-cell rhabdomyosarcoma harboring TEAD1-NCOA2 fusion of the left scapular region. The patient showed no local recurrence at the last follow-up, 4 years after being treated with chemotherapy and surgery. Our literature search identified 1323 records, of which 21 were included in the review. Conclusions: Our case report confirms the few data previously published in the literature, suggesting a good prognosis for this subset of patients. Molecularly defined ssRMSs in infants likely represent a biologically distinct entity which may not require the aggressive multimodal treatment used for other subtypes of rhabdomyosarcoma.