Metastatic clear cell sarcoma of the pancreas: A rare case report

Abstract

BACKGROUND

Clear cell sarcoma (CCS) is a rare soft-tissue sarcoma. The most common metastatic sites for CCS are the lungs, bones and brain. CCS is highly invasive and mainly metastasizes to the lung, followed by the bone and brain; however, pancreatic metastasis is relatively rare.

CASE SUMMARY

We report on a rare case of CCS with pancreatic metastasis in a 47-year-old man. The patient had a relevant medical history 3 years ago, with abdominal pain as the main clinical manifestation. No abnormalities were observed on physical examination and the tumor was found on abdominal computed tomography. Based on the medical history and postoperative pathology, the patient was diagnosed with CCS with pancreatic metastasis. The patient was successfully treated with surgical interventions, including distal pancreatectomy and splenectomy.

CONCLUSION

This report summarizes the available treatment modalities for CCS and the importance of regular postoperative follow-up for patients with CCS.

Key Words: Clear cell sarcoma, Pancreas, Metastasis, Follow-up, Case report

Core Tip: Clear cell sarcoma (CCS) is a rare soft tissue sarcoma accounting for less than 1% of sarcomas and was originally reported in 1965. CCS is a type of highly invasive cancer which mainly metastasizes to the lungs, followed by the bones and brain, but pancreatic metastasis is relatively rare. Here, we give details of the clinical manifestations and imaging features of a case of metastatic CCS of the pancreas.

INTRODUCTION

Clear cell sarcoma (CCS) is a rare soft-tissue sarcoma (STS) that accounts for less than 1% of all cases and was originally reported in 1965[1,2]. The incidence of CCS is estimated to be approximately 0.014/100000 depending on the surveillance, epidemiology and end results databases[3]. CCS originates from the tendon and aponeurosis, and is characterized by local invasive growth of the tendon and other soft tissues[4]. CCS is a highly invasive type that mainly metastasizes to the lungs, followed by the bones and brain; however, pancreatic metastasis is relatively rare[3-8]. To our knowledge, only two cases of primary pancreatic CCS have been reported[9,10]. Here, we provide details of the clinical manifestations and imaging features of a patient with metastatic CCS of the pancreas.

CASE PRESENTATION

Chief complaints

A 47-year-old male presented with abdominal pain and diarrhea.

History of present illness

Symptoms started more than a half month before presentation with abdominal pain and diarrhea.

History of past illness

No special notes.

Personal and family history

No special notes.

Physical examination

No special notes.

Laboratory examinations

No special notes.

Imaging examinations

Computed tomography (CT) and magnetic resonance imaging (MRI) revealed an isolated lesion in the pancreatic tail without metastasis (Figures 1 and 2).

Figure 1 Abdominal computer tomograph showed a 3.2 cm × 3.0 cm round lesion in the tail of the pancreas, which was uneven and mildly enhanced under enhanced scan. A: The boundary between the posterior margin and the pancreas was not clear, and was not combined with the pancreatic duct; B: Multiple lymph nodes were also seen in the mesentery area, with the width of about 1.3 cm for the largest one.

Figure 2 Magnetic resonance imaging showed an abnormal blocky signal found in the pancreato-gastric space, with a size of about 3.1 cm × 2.9 cm × 2.7 cm. The boundary between the local lesion and the pancreatic body was not clear. A: T1W1 showed equal and slightly lower signal; B: T2W1 showed a slightly higher signal. The enhanced scan showed progressive uneven enhancement.

FINAL DIAGNOSIS

The preoperative diagnosis did not rule out the possibility of CCS recurrence combined with the patient's disease history.

TREATMENT

The patient underwent surgical treatment. Under general anesthesia, the abdomen was prepped and draped in the usual fashion, with the patient in the supine position. A midline incision of the abdomen was made, and the peritoneal cavity was entered. Generalized abdominal exploration revealed no metastases to the liver, spleen, or peritoneal omentum of the abdominopelvic cavity. The gastrocolic ligament was opened in the avascular zone, and the stomach was turned upward to reveal the pancreas. A solid tumor measuring 3 cm × 3 cm × 4 cm with a hard texture and smooth surface located in the pancreatic body was found during surgery. A distal pancreatectomy and splenectomy were successfully performed. The posterior, transverse, caudal, and dorsal pancreatic arteries and pancreatic freeing were ligated. The pancreatic tissues were gradually dissected by suturing 2 cm away from the tumor, close to the neck of the pancreas. The pancreatic body and tail, and the spleen were excised. No tumor residue was found in the pancreatic margins or the spleen (Figure 3).

Figure 3 The malignant tumor of the pancreatic body was accompanied by massive necrosis. A and B: Hematoxylin and eosin (H&E) showed tumor cells arranged in nests (A; × 10), with fibrous and vascular separation around the nests (B; × 20); C: The cells were oval or polygonal, with obvious nucleoli, and some cytoplasm was lightly stained or vacuolated (H&E, × 40); D-F: No metastasis was found in the surrounding lymph nodes and no tumor involvement was found in the resection margin. Immunohistochemical results: AE1/3 (-), CD56 (-), CgA (-), CK8/18(-), HMB45(+), Melan-A (+) (D), Ki-67 (60%+), S-100 (+)(E), SOX10 (+)(F), syn (-), β-catenin (+), PR (-).

OUTCOME AND FOLLOW-UP

The patient recovered well after surgery without complications and was free of any discomfort until the last follow-up (6 mo postoperatively), with refusal of any other therapy or examination.

DISCUSSION

CCS is a malignant tumor arising from the neural spinal cells caused by the EWSR1-ATF1 gene fusion resulting from t(12;22) (q13;q12) translocation[11]. CCS often occurs in the second to fourth decades of life and affects the lower extremities. CCS metastasis to the gastrointestinal system (CCSLGT) is rare and was first reported by Zambrano et al[12] in 2003. CCSLGT is prevalent in the walls of the small intestine, stomach, colon, and peritoneum, but is rare in the pancreas[13,14]. The manifestations of CCSLGT include abdominal pain, intestinal obstruction, anemia, nausea, and vomiting. The clinical presentation in this case was abdominal pain with nausea, which is consistent with the literature.

Currently, there is no unified management method for advanced CCS, and surgery remains the standard treatment, similar to most STSs[4,7,15,16]. Ensuring that the margins of the tumor are clean and retaining a ring of normal tissue around the tumor is essential. Preoperative imaging assessment in conjunction with patient history is appropriate. CT provides initial postoperative follow-up and evaluation. MRI is an important modality that can reveal the location and extent of tumor invasion[17,18]. In this case, the patient was initially diagnosed with metastatic CCS on preoperative MRI, thus providing a good plan for surgery and ensuring clean surgical margins.

CCS has a poor prognosis, with limited effectiveness of other postoperative treatments. According to the literature, chemotherapy and radiotherapy for CCS are unsatisfactory[19-22]. Some studies have demonstrated that targeted therapy or immunotherapy may be effective; however, no confirmatory clinical trials have been conducted[23-27].

Despite optimal management of local disease, CCS has a high probability of recurrence or metastasis, and when it progresses to stages III and IV, the 5-year survival rate significantly reduces to 15%-35%[3]. Long-term follow-up is necessary for patients with CCS, because new metastatic lesions may appear after a longer period[28]. Postoperative management is important in CCS to effectively detect early metastases. In this case, the patient was not followed up after the first operation until symptoms appeared, leading to delayed treatment. At this time, the patient resisted follow-ups and examinations that would have facilitated disease monitoring.

CONCLUSION

A rare case of CCS in a patient who developed pancreatic metastases 3 years after surgery has been reported. Regularized follow-up and re-examination were not performed after the first operation, resulting in the patient being seen only after the onset of symptoms, which may have delayed the treatment. Therefore, regular postoperative follow-up is important for patients with CCS because recurrence has a long-term course.