Case report: long-term survival of an infant syndromic patient affected by atypical teratoid-rhabdoid tumor.

Background: Atypical teratoid rhabdoid tumor (ATRT) patients display a dismal median overall survival of less than 1 year. A consistent fraction of cases carries de-novo SMARCB1/INI1 constitutional mutations in the setting of the "rhabdoid tumor predisposition syndrome" and the outcome is worst in infant syndromic ATRT patients.

Case Presentation: We here describe a patient affected by mosaic Klinefelter syndrome and by rhabdoid tumor predisposition syndrome caused by constitutional SMARCB1/INI1 heterozygous mutation c.118C>T (Arg40X). Patient's ATRT primary tumor occurred at 2 years of age concurrent with metastatic lesions. The patient was rendered without evidence of disease by combined surgery, high-dose poli-chemotherapy and craniospinal irradiation, followed by autologous hematopoietic stem cell transplantation. At the onset of a spinal lesion 5.5 years later, both tumors were pathologically and molecularly evaluated at the national central pathology review board and defined as ATRT in a syndromic patient, with strong evidence of a clonal origin of the two lesions. The patient was then treated according to SIOP guidelines and is now alive without evidence of disease 24 months after the detection of metastatic disease and 90 months after the original diagnosis.

Conclusion: The report underscores the current utility of multiple comprehensive approaches for the correct diagnosis and clinical management of patients affected by rare and atypical brain neoplasms. Successful local control of disease and achievement of long-term survival is possible in ATRT patients even in the setting of rhabdoid tumor predisposition syndrome, infant age at diagnosis and metastatic spread of disease, thus justifying the efforts for the management of this severe condition.