The prevalence of umbilical cord cysts at 7-13 weeks' gestation is approximately 3%. More than 20% of such cases are complicated by structural defects and/or chromosomal abnormalities such as trisomy 18. These cysts usually have a single cavity and are <5 cm in size. Therefore, when an umbilical cord cyst is detected in the 2nd trimester, the examination of fetal karyotype is recommended. Omphaloceles are also well known to be complicated by many anomalies, especially trisomy 18. We report a case of an omphalocele associated with a large multilobular umbilical pseudocyst (diameter >5 cm) in a patient with a normal karyotype, 46XY. These anomalies were diagnosed by fetal ultrasonography. However, the cyst was difficult to diagnose as an umbilical cord pseudocyst because it was very large and multilobulated. At 38.5 weeks of gestation, the patient was delivered by Cesarean section. The cyst was resected, and the omphalocele was closed by staged surgeries. Pathologic diagnosis of the cyst was the degeneration of Wharton's jelly. This diagnosis was made by the absence of epithelial lining inside the cyst wall, since the existence of epithelial cells correlates with true cysts.

Fetal lung interstitial tumor (FLIT) is a recently reported type of congenital lung lesion comprising solid and cystic components. The pathological features include unique interstitial mesenchyme-based cell proliferation, and differ from other neoplasms represented by pleuropulmonary blastoma or congenital peribronchial myofibroblastic tumor. FLIT is extremely rare and its gene expression profile has not yet been reported. We provide the first report of a novel chromosomal rearrangement resulting in α-2-macroglobulin (A2M) and anaplastic lymphoma kinase (ALK) gene fusion in a patient with FLIT. The tumor cells contained a t(2;12)(p23;p13) and were mesenchymal in origin (e.g., inflammatory myofibroblastic tumors), suggesting the involvement of ALK in this case of FLIT. Break apart fluorescence in situ hybridization demonstrated chromosomal rearrangement at ALK 2p23. Using 5'-rapid amplification of cDNA ends, we further identified a novel transcript fusing exon 22 of A2M to exon 19 of ALK, which was confirmed by reverse-transcription polymerase chain reaction. The corresponding chimeric gene was subsequently confirmed by sequencing, including the genomic break point between intron 22 and 18 of A2M and ALK, respectively. Discovery of A2M as a novel ALK fusion partner, together with the involvement of ALK, provides new insights into the pathogenesis of FLIT, and suggests the potential for new therapeutic strategies based on ALK inhibitors.

In this study, we examined an experimental animal model of split cord malformation (SCM) produced by the surgical induction of a fistula. In Cynopus pyrrhogaster neurulae (stage 18.5 ± 0.5), the neural plate was incised and divided to construct a fistula that mimicked a neurenteric canal. After the procedure, the development of these embryos was examined morphologically and histologically. Following incubation, hemicords, hemicords with their own heminotochords, and dermal sinus were observed in histological sections of embryos with an induced fistula. These abnormalities varied with the length and duration of the fistula, and the induction of this fistula apparently caused the development of this anomaly. The histological findings resembled the findings in human cases. The results of this study support the hypothesis that SCM may originate from an accessory neurenteric canal.

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Objective: To induce experimental split cord malformations (SCMs) produced through the surgical induction of a dorsal midline fistula. Methods: In addition, the theory of embryogenesis of SCMs was verified by examining the developmental process of this experimentally induced anomaly. In Cynopus pyrrhogaster (amphibian) embryos (stage 18), the neural plate and notochord were split regionally to construct a fistula that appeared to be the ectopic neurenteric canal. Following this procedure, the embryonic development was traced morphologically and histologically. Results: Following the incubation and breeding period, split cord malformation was observed in some animals. Scoliosis, spina bifida, vertebral anomaly and subcutaneous manifestations were also observed with SCMs. Conclusions: The observations made in these experimentally induced SCMs are consistent with the findings in human SCMs. We report an experimental animal model of split cord malformation, in which double spinal cords were developed in the spinal canal. In addition, we examined the embryogenesis of SCMs. This study indicates that SCMs may arise through a process of dorsal midline fistula of the neural plate.