A primary retroperitoneal anaplastic lymphoma kinase-positive anaplastic large cell lymphoma with tumor thrombosis

Figure 1. Abdominopelvic contrast-enhanced CT scan. Notes: Black arrow: portal vein; white arrow: splenic artery; white arrowhead: splenic venous thrombus; black arrowhead: superior mesenteric vein; white hollow arrow: retroperitoneal lymphoma; black hollow arrow: the third segment of duodenum. (A) Splenic vein was replaced by longitudinal hypoattenuating mass, accompanied with splenic artery. (B) The retroperitoneal mass infiltrated the body of pancreas and splenic vein. The confluences of dilated PSPDV and coronary vein into portal vein could be seen. (C) The retroperitoneal mass involved aorta and posterior wall of duodenum. (D, E) After six cycles of chemotherapy, the splenic thrombus shrank significantly and the retroperitoneal mass disappeared. (F) The para-aorta mass and thickening of duodenum disappeared after the sixth cycle of therapy. Abbreviations: CT, computed tomography; PSPDV, posterior superior pancreaticoduodenal vein.

Figure 2. Histopathological and immunohistochemical features of the retroperitoneal mass. Notes: (A) HE staining of the tumor specimen showed atypical tumor cells with ovoid or irregular nuclei packed in sheets with intrasinusoidal infiltration. Kidney-shaped nuclei and obvious nucleoli were visible in the abundant eosinophilic cytoplasm (×400). Mitotic figures could be seen with neutrophil and plasmacyte infiltration. (B) IHC staining of EMA (×200). (C) IHC staining of CD3 (×400). (D) IHC staining of CD30 (×400). (E) IHC staining of CD56 (×400). (F) IHC staining of TIA1 (×400). (G) IHC staining of granzyme B (×400). (H) IHC staining of ALK (1A4) (×400). For all antibodies, the percentage of positive cells was semiquantitatively estimated and scored as follows: negative (−): <5% cells; weakly positive (+): 6%–30% cells; moderately positive (++): 31%~75% cells; strongly positive (+++): >75%. Abbreviation: IHC, immunohistochemistry.

Figure 3. PET-CT. Notes: (A) No sign of lymphoma was detected after the fourth cycle of chemotherapy. (B) Axial sections revealed normal size pancreas with no elevated intake of FDG (black arrow). (C) Coronal sections showed no peri-aorta lymphadenopathy (black arrowhead) or ascites. (D) Sagittal view showed slightly elevated intake of FDG in spine with normal bone structure, which was presumed as the reactive change after chemotherapy. Abbreviations: CT, computed tomography; FDG, 18F-fluorodeoxyglucose; PET, positron emission tomography.