Immature Gastric Teratoma: A Case Report.

A 3-month-old male child presented with a large abdominal mass, melena, and anemia. On imaging by X-ray, ultrasonography (USG), computed tomography (CT) plain and IV contrast and magnetic resonance (MR) screening of the abdomen showed it to be a retroperitoneal teratoma of 9.2 cm × 14 cm × 10.5 cm (AP × TR × CC) extending from epigastrium to left flank with calcification [Figure 1]. Both kidneys were normal. Hemoglobin was 6.9 gm/dl. Alpha-fetoprotein (AFP) showed an elevated level of 1220 ng/ml. Human chorionic gonadotropin was normal. After a blood transfusion, laparotomy was done which showed a surprise finding of a large Gastric Teratoma (GT). The tumor was intraperitoneal, retro gastric and dumbbell-shaped with a large exogastric and a small endogastric component in the posterior stomach wall [Figure 2a]. Excision of tumor along with a rim of the posterior wall of the stomach was done. Histopathology of both exogastric and endogastric parts of teratoma specimen [Figure 2b] showed the presence of tissues from all the three germ cell layers, immature neuroepithelial tubules, and glial cells suggestive of Norris Grade 1 immature teratoma [Figure 2c–h]. The postoperative period was uneventful. USG abdomen and AFP levels are normal during 2-years of follow-up.

Figure 1

(a) Large abdominal mass, (b) X-ray abdomen lateral view showing large retroperitoneal mass with calcification pushing the stomach superiorly and rest of the bowel inferiorly, (c) ultrasonography showing multilocular cystic mass with some solid components and calcifications suggestive of retroperitoneal teratoma. (d and e) Computed tomography plain and contrast showing large heterointense mass lesion with cystic areas, calcification and fat signal suggestive of large intraperitoneal teratoma

Figure 2

(a) Peroperative picture of large exogastric and a small endogastric component in the posterior stomach wall, (b) Excised specimen of the tumor along with the thin rim of the stomach. (c-f) Photomicrographs showing derivative of three germ layers. (c) Gastric glands, (d) squamo-columnar junction, (e) Neuroepithelial tubules, (f) Mucous acini, (g) Glial tissue, and (h) cartilage and fatty tissue

Immature GT is rare and represents 41 of 150 cases described so far. GT exhibits distinguishing characteristics and is well-known.[1] It would be appropriate to highlight the not-so oft-discussed features.

AFP >100 ng/dl is an excellent indicator of the presence of malignant components such as Yolk sac elements. Persistently high or raising levels of AFP indicate residual or recurrent tumor.[12] When the ultrasound shows normal kidneys, it excludes kidney tumors with cystic elements and calcification such as Mesoblastic nephroma and Wilms' tumor. CT with IV and oral contrast and MR imaging (MRI) shows the mass with anatomical proximity to the stomach with fat and calcification, normal kidneys, adrenals, and liver and thereby excluding renal tumor, neuroblastoma, and hepatoblastoma. CT and MRI may or may not delineate the origin from the stomach or intragastric tumor (like the case presented).[2]

Although the USG during pregnancy has become almost universal and more and more fetal MRIs are being carried out, GT was not diagnosed antenatally till now. In neonates with suspicious mass lesion with calcification suggestive of meconium peritonitis in fetal imaging[3] and nonimmune hydrops with suspicious meconium peritonitis in fetal imaging may be subjected to early postnatal CT/MRI/contrast upper gastrointestinal (GI) study[4] to confirm GT. This approach helps to plan emergency decompression of the abdomen to treat the abdominal compartment syndrome related to hydrops secondary to the mass and early and appropriate surgical procedure for complete excision.

In infants older than neonates when the teratoma has anatomical proximity to the stomach, the imaging need not show stomach wall involvement or intragastric tumor. Such cases may even have features of gastric outlet obstruction or hematemesis or melena. In these situations, early Upper GI endoscopy in stable infants may help to identify the stomach involvement or intragastric tumor and to plan appropriate surgical procedure for excision of tumor.[2] Rare recurrence of mature GT with normal AFP into mature recurrent GT with normal AFP after two decades which became tumor-free after excision of recurrent tumor is reported in one case.[5]

At present, the treatment for GT when first seen, is complete surgical excision even if there are immature elements or malignant elements and metastasis.[6] In cases of recurrent GT with elevated AFP, relook laparotomy for excision of recurrent tumor followed by chemotherapy even if recurrent tumor is not located may be a safe strategy.[1] Whether carrying out AFP immunoreactivity in all cases to improve the rate of picking up Yolk sac elements should be explored. This may be considered in the context of the only GT to have manifested postoperative malignancy in the absence of positive AFP immunoreactivity in the original resected specimen. This was explained by the possible missing AFP immunoreactivity due to a tiny cluster of Yolk sac tumor cells in the background of large neuroepithelium.[1] Postexcision follow-up is important with clinical, USG, and AFP monitoring every 3 months for 1 year, every 6 months for the next 2 years, and yearly till 7 years postexcision like in any other germ cell tumor. The possibility of late recurrence may be kept in mind and evaluation and monitoring may be extended into adulthood, if the late recurrence two decades after excision recorded in the literature[5] is considered.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient's father has given consent for images and other clinical information to be reported in the journal. The patient's father understands that the names and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.