Disseminated Congenital Malignant Rhabdoid Tumor Misdiagnosed as Multiple Congenital Hemangiomas.

To the Editor: A congenital malignant rhabdoid tumor (MRT) is a rare and aggressive growth, which is fatal in almost all patients under the age of 1 year.1 A 1-day-old girl, born at term by cesarean section due to thick meconium and fetal distress, was referred to the dermatology team for assessment of a possible vascular malformation. At birth she was noted to have a large, tense, dusky-red swelling on the left lower leg and foot, a 1 cm shiny, erythematous swelling near the left clavicle and a 4 cm erythematous mass in the left groin (Figs. 1A–D). Her full blood count and clotting were normal, but C-reactive protein was raised at 100. Ultrasound showed multiple hypoechoic lesions in the liver, left paraspinal muscles, both groins, and left leg. These masses were hypervascular, exhibiting both arterial and venous flow on Doppler imaging. According to the radiologist, the lesions were consistent with multiple congenital hemangiomas. Subsequently, magnetic resonance imaging of the whole body confirmed multiple, enhancing, soft tissue lesions involving the sites mentioned above and the differential diagnosis was widened to include neuroblastoma and sarcoma. At 7 days of age, a skin biopsy was taken from the left lower leg lesion and showed diffuse infiltration of the dermis and subcutaneous tissue by sheets of large atypical cells with rounded and vesicular nuclei, prominent nucleoli, and abundant clear cytoplasm (Figs. 2A–C). Tumor cells showed coexpression of vimentin and epithelial markers (keratins and epithelial