Presentation
Back pain.
Patient Data
CT Abdomen and pelvis
Extensive retroperitoneal mass on the left likely represents coalescent lymphadenopathy, partially encasing the anteriorly displacing the aorta and IVC, as well as causing proximal ureteral obstruction with severe left hydronephrosis. Most of the fat planes between the mass and adjacent retroperitoneal structures are not clearly identified. Small fat containing umbilical hernia.
Testicular US
Selected image from testicular ultrasound showing a focal hypoechoic mass within the inferior pole of the left testis. The remainder of the scrotum (not shown) was normal.
This patient was worked up for possible lymphoma, and thus a CT-guided core-biopsy of the retroperitoneal masses was performed:
Macroscopy: "Retroperitoneal mass". Two pale tan cores of tissue and hemorrhage,
measuring <1mm and 5mm.
Microscopy: The biopsy fragments consist of fibrous connective tissue which includes an infiltrate of small reactive lymphocytes and a population a large atypical cells forming either sheets or poorly defined nests. These cells have irregular nuclear membranes with prominent nucleoli, and a small to moderate amount of pale cytoplasm. The large atypical cells show weak positive immunostaining for broad-spectrum cytokeratin (AE1/3). These immunomarkers are negative in the atypical cells: CD20, CD5, Bcl2, cyclinD1, CD10 (lymphoma markers) and S100 (melanoma marker).
Conclusion: Retroperitoneal mass, core biopsy - Probable metastatic poorly differentiated carcinoma. Additional immunostains show positive tumor cell marking for PLAP, with no staining for CD30, CK7, CK20 or pan-cytokeratin. Although the sample is small, the morphology and immunobinding are consistent with a diagnosis of metastatic seminoma.
Case Discussion
The patient was then submitted to further left radical orchiectomy:
Microscopy: The entire testis has been submitted. The sections from the lesion adjacent to the rete testis show an irregular zone of interstitial fibrosis and which is accompanied by the proliferation of small blood vessels and a patchy stromal infiltrate of lymphocytes. The adjacent testicular parenchyma shows evidence of tubular atrophy with eosinophilic thickening of tubular basement membranes and focally prominent interstitial clusters of Leydig cells. Focally, the lining of the adjacent seminiferous tubules is partly replaced by a population of large atypical cells that have very prominent nucleoli and abundant clear cytoplasm. These cells show positive staining with PAS, as well as the immunomarkers ckit and PLAP, consistent with intratubular germ cell neoplasia, unclassified type. The vast majority of the testicular parenchyma is unremarkable. The macroscopically described spermatic cord nodule is epididymal tissue which is within normal limits.
Diagnosis: Left orchiectomy: Testicular parenchymal fibrous scar, consistent with burned out germ cell
tumor, with adjacent intratubular germ cell neoplasia (ITGCN). No invasive germ cell tumor identified.
Therefore, this case illustrates the spontaneous regression of a primary testicular seminoma that happened after the demonstration of retroperitoneal nodal metastases. This is known as a burned-out testicular seminoma.