PMC5287970_01
Abdominal MRI (A, B): nodular low-signal shadow (white arrow) was seen at the lower segment of common bile duct. Abdominal contrast-enhanced CT (C, D): nodular high-intensity shadow (white arrow) was observed in the upper duodenum. (Black arrow indicating nasobiliary drainage). CT = computed tomography, MRI = magnetic resonance imaging.
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F1
Lesions of the head of pancreas were found (Fig. 1A, B). Enhanced scan revealed no obvious enhancement, and the diameter was about 1.2 cm (Fig. 1C, D).
Postoperative specimen: spherical tumor at the head of pancreas, measuring 3 cm in diameter. It was composed of a fish-shaped gray matter and a hard structure resembling spongy bone in close proximity.
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F2
These two components were in close proximity (Fig. 2).
(A) Hematoxylin-Eosin (HE) staining x40: adenocarcinoma (right lower part) with dysmorphic spindle cell proliferation (right upper part) and neoplastic osteogenesis (left lower part). (B) HE x100: adenocarcinoma composed of moderately differentiated dysmorphic and proliferating pancreatic duct-like structure. Spindle cells in the osteosarcoma region were obviously dysmorphic. Pathological mitotic and neoplastic osteogenesis was observed. (C) Immunohistochemical (IHC) staining: cytokeratin7-expression in adenocarcinoma, but not in osteosarcoma (Envision method, x200). (D) IHC: vimentin-expression in osteosarcoma, but not in adenocarcinoma (Envision method, x200).
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F3
The pancreatic tumor was confirmed as carcinosarcoma consisting of moderately differentiated adenocarcinoma and heterologous mesenchymal osteosarcoma (Fig. 3A, B). The tumor originated in the pancreatic duct and contained malignant spindle cells (Fig. 3C), accompanied by mononuclear and giant polymorphonuclear cells. Osteoid and bony tissues of mesenchymal origin were found (Fig. 3D).