Contributed by
Advent Health
Avinash Mamgain MD, Brett Eckert MD, Jennifer Williams MD, Felix Gonzalez MD, Joshua Franklin MD, Kurt Scherer MD, and Christopher Wasyliw MD.
History
Two-week-old male with a large left foot mass detected prenatally; postnatally there is a plantar–hindfoot mass, skin dimples, a right groin node, and an intracardiac echogenic mass.
Infantile myofibromatosis (IM) is a rare soft tissue neoplasm typically diagnosed in early infancy of fibroblastic/myofibroblastic origin. IM may present as a solitary lesion or multicentric disease with or without visceral involvement. While most cases are sporadic, certain genetic mutations have been implicated such as the PDGFR-Beta gene. IM is seldomly diagnosed prenatally with most cases diagnosed during infancy or early childhood. Although rare, prenatal detection of IM can give the opportunity for perinatal counseling/management. Here, we present a case of a lower extremity IM detected on prenatal ultrasound with further characterization on subsequent fetal MRI. Final pathology in this case established IM harboring a PDGFR-Beta fusion gene, an increasingly recognized molecular driver within the IM spectrum that can refine diagnosis and may expand therapeutic considerations.
OB Detail Fetal Anatomy grey-scale ultrasound of the fetal left foot demonstrates a large hypoechoic heterogeneous soft tissue mass measuring 6.5 x 6.5 x 5.2 cm.
Fetal MR TrueFISP sagittal images demonstrate a large heterogeneous mass arising from the left foot measuring up to 7.3 x 5.0 x 5.8 cm. The mass is predominantly low T2 signal, with heterogeneity/scattered regions of slightly T2 hyperintense areas noted throughout. There are no large flow voids/vessels or restricted diffusion seen. There are a few regions of T1 bright signal in portions of the mass noted. No normal foot bones formation.
Fetal MR TrueFISP coronal image demonstrates large heterogeneous mass arising from the left foot measuring up to 7.3 x 5.0 x 5.8 cm. The mass is predominantly low T2 signal, with heterogeneity/scattered regions of slightly T2 hyperintense areas noted throughout. There are no large flow voids/vessels or restricted diffusion seen. There are a few regions of T1 bright signal in portions of the mass noted. No normal foot bones formation.
Fetal MR TrueFISP axial image demonstrates large heterogeneous mass arising from the left foot measuring up to 7.3 x 5.0 x 5.8 cm. The mass is predominantly low T2 signal, with heterogeneity/scattered regions of slightly T2 hyperintense areas noted throughout. There are no large flow voids/vessels or restricted diffusion seen. There are a few regions of T1 bright signal in portions of the mass noted. No normal foot bones formation.
Postnatal MRI T2 STIR sagittal image demonstrates large lobulated left foot mass surrounding the foot bones extending from the hindfoot to the proximal toes measuring approximately 6 x 4.5 x 5 cm. The mass has heterogenous STIR signal suggesting fibrous content or high cellularity.
Postnatal MRI T1 with contrast subtraction coronal image demonstrates rapid arterial enhancement of the mass. Prominent draining veins are present at the posterior aspect of the lower leg.
