Fetal lung interstitial tumor (FLIT) is a rare fetal malignancy that is typically diagnosed in the postnatal period, or, if recognized prenatally can mimic a benign lesion such as congenital pulmonary airway malformation. We present the earliest case of a FLIT tumor described by ultrasound and MRI at 26 weeks of gestation. Our case highlights features suggestive of FLIT including presentation later in gestation in combination with findings on fetal MRI such as a solid appearance with radiating curved bands of high signal within and along the periphery of the lesion (not as intensely high signal as the typical CPAM), possibly detailing a radiographic signature for these tumors. The role of betamethasone for these tumors is not known.
Keywords: Fetal lung interstitial tumor; congenital pulmonary airway malformation; immature mesenchymal interstitial tumor.