A 71-year-old man was admitted because of abdominal pain in January 2003. His past medical history was significant for a monoclonal gammopathy and surgery for hip prosthesis 2 years before the current admission. At another hospital an abdominal computed tomography (CT) scan had revealed a left-sided mass (10 × 9 cm) involving the diaphragm, spleen, and, from the outside, the left colon flexure. Tumor marker (CEA and CA19-9) serum levels were normal, with the exception of serum AFP, which was markedly elevated (44074.6 ng/ml). However, no CT evidence of primary hepatocellular carcinoma was found. Endoscopy of the upper and lower gastrointestinal tract did not show any primary tumor. A FNAB was performed and cytologic analysis was consistent with a moderately differentiated adenocarcinoma.
Since surgery was deemed not to be feasible, 5-fluorouracil and oxaliplatin-based chemotherapy was administered for a total of 6 cycles, resulting in stable disease.
As the abdominal mass was shown to have slightly shrunk (Figure ), a laparotomy was scheduled with the aim to perform a radical operation in July 2003. Unfortunately, along with spleen and left colon, the tumor was found to infiltrate a large part of the left diaphragm thus making it difficult to remove the entire mass. A segmental resection of the left colon (left transverse colon, splenic flexure, and proximal part of the descendent colon) along with splenectomy was performed. A small part of the tumor was left in place (figure ).
CT scan before the treatment showing the mass lesion.
The gross appearance of the operated specimen was that of a lobulated, compact, yellow-greenish mass immersed in an adipose-like stromal tissue. Included in the pathological evaluation were also the spleen (12.5 × 6.0 cm), a 7-cm intestinal tract, and tissue samples from colon serosa (6.0 cm), omentum (19 × 18 cm), diaphragm (4.5 × 3.0 cm), peritoneum (8.5 × 3.5 cm), transverse mesocolon (2.5 × 2.0 cm), and pancreatic tail lymph nodes. The spleen had an irregular surface due to the presence of multiple, small gray-whitish nodules, which were also observed in the context of the other sampled tissues. The maximum diameter of the nodules was 2.5 cm. Microscopically, each nodule appeared to be made of single or multiple layers of cells, sometimes with branchlike divisions or in islet-like configuration. Cells in the nodules had polygonal appearance, acidophilic cytoplasm, and large, single or multiple hyperchromatic nuclei, often with vacuolization. These cells stained positive for AFP on immunohistochemistry (Figure ). In addition, features of well-differentiated liposarcoma were found on colon serosa. In particular, lobules of adipocytes with large and vacuolized cytoplasm were observed. At higher magnification, interspersed lipoblasts with large, hyperchromatic nuclei could be identified. On immunohistochemistry, lipoma-like cells stained positive for S100, vimentin and calretinin but not for p53, p21 WaF1, and c-kit, indicating a well-differentiated liposarcoma.
Photomicrograph Showing collision of hepatoid carcinoma (left-up corner) and liposarcoma (left down corner) (H&E × 100 magnification).
Finally, a collision zone between the two tumors was identified, consisting of a large area infiltrated by islets or layers of AFP-positive, acidophilic, polygonal cells in contiguity and continuity with islets of lipoblast-rich fat tissue (well-differentiated liposarcoma).
The serum AFP level decreased after surgery (9000 ng/ml). The patient received first line chemotherapy with liposomal doxorubicin for 8 cycles resulting in disease control for 2 years. The patient then had hepatic metastases and died 3 years after the first diagnosis.