Synchronous Occurrence of Advanced Gastric Carcinoma with Retroperitoneal Liposarcoma: A Case Report

Abstract

BACKGROUND Gastric carcinoma (GC) remains one of the most common and deadly neoplasms in the world. Liposarcoma (LPS) is the most common sarcoma of adults. However, synchronous or metachronous occurrence of GC with LPS seems to be very rare. Tumor staging and differential diagnosis with these cases are extremely difficult. CASE REPORT The patient was a man in his 70s, who reported anorexia and weight loss of 4 kg over 2 months. Gastroscopy demonstrated a large tumor of Borrmann type 3, of which histology was moderately to poorly differentiated adenocarcinoma. The clinical stage was initially defined as IVb due to a 11×6 cm retroperitoneal (RP) tumor. Despite chemotherapy for GC, the RP tumor rapidly enlarged. Endoscopic ultrasound-guided fine-needle aspiration biopsy showed that it was an undifferentiated sarcoma. He died of hepatorenal failure secondary to severe jaundice. The autopsy revealed a synchronous occurrence of GC and RP sarcoma. GC had no areas admixed with sarcoma. Histology of RP sarcoma showed that it mainly consisted of undifferentiated sarcoma and focally of well-differentiated LPS characterized by well-differentiated adipocytes admixed with scattered atypical stromal cells. The tumor cells in both areas were positive for MDM2 and CDK4 by immunohistochemistry. The diagnosis of the RP sarcoma was revised to dedifferentiated LPS. CONCLUSIONS There were no previous case reports of synchronous occurrence of GC with LPS in the English and Japanese literature. GC and LPS pose challenging problems in their diagnoses, staging, and treatments when they occur synchronously or metachronously.

Figure 1.

(A) Two up to 3.3-cm enlarged lymph nodes (yellow arrows) involving gastric regional lymph nodes. (B) A large, 11×6 cm, retroperitoneal tumor (orange arrows). The lesion was unusual in its large size and heterogeneous density compared with an ordinary GC nodal metastasis.

Figure 2.

A Borrmann type 3 antral tumor with stenosis of the stomach on gastroscopy.

Figure 3.

Gastric biopsy revealed a moderately to poorly differentiated invasive adenocarcinoma. H&E original magnification (OM) ×200.

Figure 4.

(A) After therapy, the regional lymph nodes decreased in size in comparison with Figure 1a (yellow arrow). (B) The RP tumor rapidly increased in size from 11 cm to 16 cm during therapy (orange arrows).

Figure 5.

EUS-FNA of the RP tumor showed a proliferation of atypical spindle cells arranged in sheets. H&E OM ×200.

Figure 6.

Gross examination at autopsy demonstrated the retroperitoneal tumor near the aorta (white arrows) and pancreas (red arrow) with massive central necrosis (white arrow heads) and invasion into the large vessels (red arrow heads).

Figure 7.

(A) Histology of the retroperitoneal tumor showed a monotonous proliferation of undifferentiated cells with a vaguely storiform pattern. H&E OM ×200. (B) Histology showed that focal areas of the RP tumor had well-differentiated LPS characterized by mature adipocytes and scattered atypical stromal cells. H&E OM ×200.

Figure 8.

(A) Many tumor cells within the dedifferentiated areas are positive for MDM2. MDM2 OM ×200. (B) Scattered cells are positive for MDM2 in the well-differentiated LPS areas. MDM2 OM ×200.