Autoimmune diseases are rare in patients with severe combined immunodeficiency (SCID). The authors describe an 11-month-old infant girl with SCID with fatal warm autoimmune hemolytic anemia (AIHA) resulting from IgM autoagglutinins. Serologic evaluation revealed IgM autoantibodies that caused in vitro hemagglutination at 37 degrees C. The patient had clinical evidence of ongoing hemolysis and agglutination despite aggressive treatment. She had three strokes and died 6 weeks after unsuccessful bone marrow transplantation. Autoimmune disease is an unexpected complication of SCID. The presence of warm reactive IgM autoagglutinins in AIHA confers a dismal prognosis.

Malignant rhabdoid tumors (MRTs) are well recognized in the kidney and extrarenal sites such as soft tissues, retroperitoneum, and bladder but are classified as atypical teratoid/rhabdoid tumors in the central nervous system. The unifying features of both extracranial MRT and atypical teratoid/rhabdoid tumors are the exon deletions/mutations of the SMARCB1 (SWI/SNF related, matrix associated, actin dependent regulator of chromatin, subfamily b, member 1) gene in 22q11.23 and resulting loss of SMARCB1/INI1 (integrase interactor 1) protein expression by immunohistochemistry. We herein report a case of extrarenal rhabdoid tumor confined to the bladder in a 3-year-old child, diagnosed by histopathology and confirmed by immunohistochemical and molecular studies. This is only the fourth molecularly proven primary MRT of the bladder to be reported. The patient’s peripheral blood was negative for the deletions observed in the tumor, thereby confirming a sporadic origin for the tumor. Given the possible dismal outcome, urgency for definitive diagnosis to institute intensive multimodality therapy, histopathologic differential diagnosis with rhabdomyosarcoma and urothelial carcinoma with rhabdoid features, and lack of consensus management guidelines, oncologists, urologists, and pathologists must be aware of this entity. Evaluation for a germ line SMARCB1 alteration may greatly aid risk stratification and family planning.