Case report: Extraskeletal mesenchymal chondrosarcoma with a rare metastasis to the pancreas

Abstract

Background: Extraskeletal mesenchymal chondrosarcoma (ESMC), an uncommon and highly aggressive form of chondrosarcoma, is characterized by its mesenchymal origin and absence of skeletal involvement. Only a few cases of primary ESMC with metastasis to the pancreas have been reported so far. In this study, we present a case of ESMC in the left thigh with a solitary pancreatic metastasis in a 45-year-old woman. Additionally, we provide a thorough overview of ESMC, encompassing its entire clinical progression and radiographic observations. Furthermore, we reviewed all thirteen cases of pancreatic metastasis, including this present case, analyzing patient attributes, clinical management, and prognosis.

Case presentation: A 45-year-old woman has had a painless mass in her left thigh for one year. X-ray, computed tomography (CT), and magnetic resonance imaging of the left thigh were performed. Positron emission tomography-CT imaging showed a high accumulation in the left thigh tumor and the pancreatic neck lesion. A diagnosis of extraskeletal chondrosarcoma with pancreatic metastasis was determined based on the radiological examinations. A final diagnosis of ESMC was confirmed by histopathological and immunohistochemical examinations after surgical resection. The patient presented metastasis in the lung, right groin, and tail of the pancreas successively, and mostly received complete surgical excision during a 39-month follow-up with postoperative chemotherapy.

Conclusion: We present a highly uncommon case of ESMC spreading to the pancreas and highlight the importance of recognizing the distinctive imaging features of ESMC for diagnosis and prognosis assessment.

Keywords: case report; contrast-enhanced computed tomography; magnetic resonance imaging; mesenchymal chondrosarcoma; metastasis; soft tissue neoplasms.

Figure 1

Plain X-ray, CT, MRI, and PET-CT images of the lesion in the left distal thigh (the lesion is indicated by the hollow arrow). Anteroposterior (A) and lateral (B) plain x-ray showed an oval soft tissue mass with spotty calcifications. Axial CT of soft tissue window images in the unenhanced (C) and enhanced (D) phases. Axial MRI images of the tumor mass on non-contrast T1-weighted (E), T2-weighted fat-suppression (F), and T1 enhanced (G) images. Axial PET-CT images of the lesions in the left distal thigh (H, I).

Figure 2

CT, MRI, and PET-CT images of the lesion in the neck of the pancreas (the lesion is indicated by the hollow arrow). Plain CT axial image (A), arterial phase of contrast-enhanced CT axial (B) and coronal (C) images of the abdomen. The axial multi-sequence MRI images of the pancreas on DWI (D), a ADC* image (E), a T1-weighted image (F), a T2-weighted fat-suppression image (G), and a T1 enhanced image (H). Coronal T1 enhanced image (I) of the lesion in the neck of the pancreas. Axial PET-CT images of the lesions in the neck of the pancreas (J, K).

Figure 3

Histomorphological staining results of the tumors in the thigh and the pancreas with hemotoxylin and eosin, and partial immunohistochemical staining results of the pancreatic metastasis. (A) Combination of cartilaginous islands and undifferentiated small cells with an abrupt transition between them. The hollow star indicates the cartilaginous islands (0riginal magnification, ×100). (B) The component of the primitive undifferentiated mesenchymal cell shows a small round to oval cellular appearance with scant cytoplasm bearing a considerable resemblance to myopericytoma with numerous vascular clefts. The hollow arrow indicates small round cells (original magnification, ×200). (C) The metastatic tumor in the pancreas morphologically resembles that in the thigh (A, B). The hollow arrow indicates the normal pancreas tissues, and the hollow star indicates the chondroid matrix. (original magnification, ×100). (D) Immunohistochemical staining with CD99 in a cartilaginous island. The hollow arrow indicates positive staining (original magnification, ×200). (E, F) Immunohistochemical staining with S-100. The hollow arrow indicates positive staining (original magnification, ×100 and ×200). (G, H) Immunohistochemical staining with NKX 3.1. The hollow arrow indicates positive staining (original magnification, ×100 and ×200).

Figure 4

The timeline of diagnosis and treatment.