case_images: PMC8256245_01
case_images: Case-1: (a) axial abdomen CT scan with contrast (venous phase) on 7th October 2018,
  shows a large retro-duodenal mass displacing the second part of the duodenum
  anteriorly and compressing the IVC, (b) sagittal CT scan with contrast shows large
  retroperitoneal mass invading the duodenum that appears displaced anteriorly, (c) CT
  scan with contrast on the 24th June 2019 shows progression in size of the
  retroperitoneal mass with more invasion of the duodenum, (d) low power magnification
  of the bowel wall with ulceration, with underlying immature cartilage consistent with
  the teratomatous component of the germ cell tumor (H&E, x20), (e) squamous
  epithelium and glandular component are other components of teratoma (H&E, x20),
  and (f) cartilaginous component is seen in other foci (H&E, x20).
case_images: 10.1177_20363613211029487-fig1.jpg
case_images: PMC8256245_01_10.1177_20363613211029487-fig1.jpg
case_images: fig1-20363613211029487
case_images: Further investigation by CT scan demonstrated a large mass lesion posterior to the second part of the duodenum which is displaced anteriorly (Figure 1(a) and (b)), compressing and stretching the inferior vena cava (IVC). A CT-scan revealed progression in the size of the retro-duodenal mass (Figure 1(c)). The tumor was composed of choriocarcinoma (50%), and mature cystic teratoma (50%), showing ulceration of the overlying mucosal lining (Figure 1(d)), with squamous and glandular epithelium (Figure 1(e)), and cartilage (Figure 1(f)) as the main components of the teratoma.
case_images: PMC8256245_02
case_images: Case-2: (a) abdomen CT scan with contrast (venous phase) on the 11th December 2015
  shows a retroduodenal mass measuring 6 cm that appears inseparable from the posterior
  duodenal wall. There is also left para-aortic metastatic lymph node with similar
  features, measuring 1.8 cm, (b) a group composed of cells with large clear cytoplasm,
  vesicular nuclei, with a single prominent nucleoli (H&E, x40), (c) SALL-4
  immunostain is positive in the tumor cells (x20), confirming the diagnosis, (d)
  scrotal ultrasound was performed on the 25th February 2016. Both testicles are normal
  in size, homogeneous with good color flow mapping in both testes. There were multiple
  calcific foci in the stroma bilaterally, more prominent on the right, but with no
  definite solid mass lesion seen. (e) Abdomen CT scan with contrast (venous phase) on
  the 12th April 2016 after two cycles of chemotherapy showing regression of the
  retroduodenal mass from 6 to 2 cm. The left para-aortic lymph node has regressed from
  1.8 to 0.6 cm. (f) Abdomen CT scan with contrast (venous phase) on the 28th June 2016
  showed further regression of the retroduodenal mass with residual post-treatment
  thickening that measured 1 cm. There was no evidence of left para-aortic lymph node
  enlargement.
case_images: 10.1177_20363613211029487-fig2.jpg
case_images: PMC8256245_02_10.1177_20363613211029487-fig2.jpg
case_images: fig2-20363613211029487
case_images: An abdominal CT scan revealed a 6 cm right upper retroperitoneal and abdominal mass (Figure 2(a)). Review of his original pathological slides revealed a germ cell tumor with large areas of necrosis, as well as focal granulomatous reaction (Figure 2(b)). SALL4 (Figure 2(c)), OCT 3/4, and CD30, with focal positivity for pan CK AE1/E3. Scattered groups of tumor cells were positive for Glypican3. Testicular ultrasound showed multiple small calcific foci that could represent microlithiasis (Figure 2(d)). He had excellent response to chemotherapy with regression of the tumor noted in April (Figure 2(e)) and June 2016 (Figure 2(f)).