Fetal lung interstitial tumor: Prenatal presentation of a rare fetal malignancy

Spontaneous Partial Regression of Fetal Lung Interstitial Tumor With A2M::ALK Rearrangement in a Neonate

The differential diagnosis for neonatal primary lung masses includes developmental anomalies and congenital lung tumors. Fetal lung interstitial tumor (FLIT) is a rare benign mesenchymal lesion which presents either antenatally or within the first 3 months of age. FLIT is a circumscribed solid-cystic mass which histologically resembles the fetal lung during the canalicular stage at 20-24 weeks of gestation. It is composed of immature mesenchymal cells expanding the interstitium and irregular airspace-like structures. Of all published cases, only 1 identified an α2-macroglobulin (A2M)::anaplastic lymphoma kinase (ALK) fusion and all cases underwent surgical resection in the neonatal or infancy period. We present the second case of FLIT with an A2M::ALK fusion diagnosed postnatally in a neonate which partially regressed spontaneously during conservative management with interim resection at 39 months of age, and provide a review of the literature.

Fetal Lung Interstitial Tumor (FLIT): Review of The Literature

Fetal lung interstitial tumor (FLIT) is an extremely rare pediatric lung tumor that shares radiological features with congenital pulmonary malformations (cPAM) and other lung neoplasms. A review of the literature, together with the first European case, are herein reported. A systematic and manual search of the literature using the keyword "fetal lung interstitial tumor" was conducted on PUBMED, Scopus, and SCIE (Web of Science). Following the PRISMA guidelines, 12 articles were retrieved which describe a total of 21 cases of FLIT, and a new European case is presented. A prenatal diagnosis was reported in only 3 out of 22 (13%) cases. The mean age at surgery was 31 days of life (1-150); a lobectomy was performed in most of the cases. No complications or recurrence of disease were reported at a mean follow-up of 49 months. FLIT is rarely diagnosed during pregnancy, may present at birth with different levels of respiratory distress, and requires prompt surgical resection. Histology and immunohistochemistry allow for the differentiation of FLIT from cPAM and other lung tumors with poor prognosis, such as pleuropulmonary blastoma, congenital peri-bronchial myofibroblastic tumor, inflammatory myofibroblastic tumor, and congenital or infantile fibrosarcoma.

A case report of misdiagnosed fetal lung mass and review of the literature

The patient was a male neonate, and a prenatal ultrasound had detected a right lung mass. He was born at term and after delivery had tachypnea and feeding difficulties. A chest x-ray and a computed tomography (CT) scan revealed a large mass in the right chest with compression on the right lung after birth. We initially considered congenital pulmonary airway malformation (CPAM). After conservative treatment, his respiratory symptoms worsened gradually, and he required continuous supplemental oxygen. The symptoms could not be relieved by puncturing due to a postnatal ultrasound having shown a mass with anechoic microcystic spaces. He therefore underwent an emergency thoracotomy and lobectomy at 14 days of age. The pathology was consistent with fetal lung interstitial tumor (FLIT). The patient remained healthy at the three-month follow-up. We reviewed the literature on FLIT and found that, to date, 23 cases have been reported worldwide.

Fetal lung interstitial tumor: An uncommon pediatric pulmonary neoplasm

Fetal lung interstitial tumor (FLIT) is a rare pediatric lung tumor with radiological features similar to developmental pulmonary malformations and other congenital lung neoplasms. There are about 17 cases of FLIT reported worldwide till date. We report the first case of FLIT in the Indian literature which was diagnosed in the early postnatal period (at the 21^st day of life) by pathological examination. The tumor exhibited a novel focal micropapillary architecture, in addition to the previously described microscopic features. We discuss the pathogenesis and differential diagnoses of FLIT and review the literature.

Fetal ultrasound and magnetic resonance imaging: a primer on how to interpret prenatal lung lesions

Fetal lung lesions include common lesions such as congenital pulmonary airway malformation (CPAM), bronchopulmonary sequestration (BPS) and combined CPAM-BPS hybrid lesions, as well as less common entities including congenital lobar emphysema/obstruction, bronchial atresia, bronchogenic cysts and rare malignant pulmonary lesions such as pleuropulmonary blastoma. Fetal lung lesions occur in approximately 1 in 15,000 live births and are thought to arise from a spectrum of abnormalities related to airway obstruction and malformation, with the lesion type depending on the timing of insult, level of bronchial tree involvement, and severity of obstruction. Lesions vary from small and asymptomatic to large and symptomatic with significant mass effect on surrounding structures. Accurate diagnosis and characterization of these anomalies is crucial for guiding patient counseling as well as perinatal and postnatal management. The goal of this review is to provide an overview of normal fetal lung appearance and imaging features of common and uncommon lesions on both ultrasound and MR imaging, and to discuss key aspects in reporting and evaluating the severity of these lesions.

Pediatric thoracic mass lesions: Beyond the common

Thoracic mass lesions can be categorized as originating in one of the three major compartments: a) chest wall and pleura, b) lung parenchyma and airways, c) mediastinum. While some of these, such as lymphoma, are common in both children and adults, others are rare and unique to childhood. The goal of this review is to familiarize radiologists with unusual but distinctive mass lesions of the pediatric thorax.