Dual pathology a case report of yolk sac component in mature gastric teratoma

Abstract

Gastric teratoma is a rare tumour accounting for less than 1% of all teratomas in pediatric age groups. We present a case of gastric teratoma in 33-month-old male infant who presented with abdominal pain for 2 months. Ultrasound of abdomen revealed a multi-cystic mass with mixed echogenicity arising from the lesser curvature of stomach. The mass was excised completely and sent for histopathological examination. Histopathology confirmed mixed germ cell tumour (gastric mature teratoma and yolk sac tumour). Serum AFP (alpha fetoprotein) and extensive sampling of the lesions can help in identification of other germ cell component. Introduction Gastric teratoma accounts for less than 1% of teratomas in pediatric age groups. A majority of the lesions are seen in the neonatal period. Gastric teratomas are the most common terartomas of gastro-intestinal tract, with oropharynx and tongue being other common sites. Since report of the first gastric teratoma in 1922, about 112 cases have been documented in literature. Case Report Case History: A 33-month-old male child presented with anaemia and pain abdomen for a duration of 2 months. Prior surgical history of laparotomy for similar complaints one and half year back. Previous histopathological report showed the lesion was diagnosed as immature gastric teratoma. Per abdomen examination showed an intra-abdominal mass, predominantly in the left upper quadrant of abdomen. AFP (alpha fetoprotein) was significantly raised (559.8 IU/ml). Ultrasonography showed a multi-cystic lesion with mixed echogenicity attached to lesser curvature. Operative findings showed a multi-cystic lesion displacing the stomach anteriorly and pancreas laterally. A complete excision of the tumour was performed. Gross examination of the lesion revealed an encapsulated lesion measuring 15x12x8, on cut section mass had a solid-cystic areas with a variegated appearance along with foci of cartilage, sero-mucinous secretions, area of necrosis and haemorrhage. Light microscopy showed derivatives from all three germ cell layer. Endodermal components such as smooth muscles, intestinal wall, respiratory epithelium and pancreatic acini were seen. Mesodermal components such as cartilage and ectodermal component in the form of stratified squamous epithelium with keratin was also seen. Focal areas of yolk sac tumour component composed of tumour cells in alveolar and trabecular pattern having vesicular nuclei and inconspicuous nucleoli. Pathognomic finding of Schiller Duval body was also observed. No angiolymphatic invasion was appreciable. A final diagnosis of mixed germ cell tumour (mature gastric teratoma with yolk sac tumour (YST)) was done. Fig. 1: Photomicrograph showing mature teratoma with ectodermal componentstratified keratinizing squamous epithelium, low power magnification (100x, H&E stain) Article Info Received: 9th February, 2019 Accepted: 6th March, 2019 Published Online: 9th August, 2019