A Complex Case of Diffused Malignant Extra-Renal Rhabdoid Tumor in a Newborn

Malignant rhabdoid tumor (MRT), first described by Beckwith and Palmer in 1978 as a variant of Wilms' tumor, is an aggressive neoplasm with early onset and poor prognosis. Malignant extra-renal rhabdoid tumors (MERTs) can arise in various locations and often present at birth as a disseminated disease without an identifiable primary site, posing significant diagnostic and therapeutic challenges. This case highlights the complexity of diagnosing an 11-day-old preterm infant with multiple enlarging masses, including a hypervascular forehead lesion, parotid mass, and soft tissue masses in the leg and hip. Initial imaging, pathology, and immunohistochemistry findings were inconclusive, necessitating advanced molecular studies, which ultimately confirmed MRTs through the loss of SMARCB1 expression. However, the diagnosis was delayed due to overlapping differential considerations, including fibrosarcoma and other sarcomas. Despite extensive multidisciplinary efforts and tailored treatments, the tumors progressed aggressively, emphasizing the challenges in diagnosing and managing such rare conditions. Given their complexity, MERTs require a comprehensive diagnostic approach combining clinical evaluation, histopathological analysis, and molecular studies, with a high level of clinical suspicion essential for timely treatment.