Atif A Ahmed
Children’s Mercy Hospital, USA
Title: Molecular testing in histologically benign spindle cell proliferations
Biography
Biography: Atif A Ahmed
Abstract
Histologically low grade spindle cell tumors in children are mostly benign and easily cured. Infrequency, such tumors can be infiltrative, commonly recur and are difficult to classify and surgically excise. Molecular tests including next generation seuencing have greatly faciltated the diagnosis and the treatment of highly malignant tumors but are rarely ultized in the management of undifferentiated low grade spindle proliferations. In the last three years, we have encountered two unusual cases of histologicaly benign infiltrative spindle cell proliferation in children that were studied by whole exome sequencing. The first case was that of a 20-cm abdominal mass that extended to the pelvis in a young child. The histology revealed bland spindle cell proliferation that infiltrated skeletal muscles and adipose tissue. The CD34-positive cells did not show any immunoreactivity to any other marker. Whole exome sequencing revealed NF1 gene mutation suggesting origin from peripheral nerve sheath. The second case was that of an infant who had right a nasal tumor involving the maxillary sinus and turbinates and extending to the skull base. The recurrent tumor shows focal early osteoid formation and was negative for ALK, CTNNB1 and GNAS mutations. Exome sequencing revealed RET Glu511Lys variant. In both cases, potential benefit by several tyrosine kinase inhibitors was revealed. In conclusion, molecular sequencing for actionable mutations is valuable in the management of low grade infiltrative spindle cell lesions in children.