Metastatic pancreatic solitary fibrous tumor: A case report

Abstract

Background: Solitary fibrous tumor (SFT) is a rare mesenchymal tumor that is most commonly found in the pleura but can also originate from non-pleural sites. Among the non-pleural localizations, the pancreas is extremely rare. In particular, metastasis to the pancreas from the central nervous system (CNS) is extremely rare, with only two cases reported so far. We report a case of recurrence in the pancreas 14 years after the initial complete surgical removal of a tumor in the CNS.

Case summary: A 68-year-old man with a past medical history of recurrent meningeal hemangiopericytoma, currently referred to as SFT, presented to the hospital with jaundice. The patient was first diagnosed with an 8cm-sized meningeal hemangiopericytoma fourteen years ago and underwent osteoplastic craniotomy. After 16 mo, imaging showed recurrence and he underwent gamma knife radiosurgery (GKRS). 2 years later, imaging showed recurrence again leading to a second GKRS. 5 years later, recurrence was again suspected leading to a second craniotomy. Since then 3 years had passed, and imaging showed a 3.5cm-sized mass lesion on the pancreatic head with obstruction of the pancreatic and bile ducts. Endosonography with fine-needle aspiration biopsy was done preoperatively and aided in the diagnosis of SFT. The patient underwent pylorus-preserving pancreaticoduodenectomy. Pathologic findings of the resected pancreatic specimen, consistent with the previously resected brain specimen, confirmed the diagnosis of SFT.

Conclusion: The rarity and lack of knowledge about SFTs make suspecting and diagnosing this disease challenging. We believe that a report of metastatic pancreatic SFT from the CNS will contribute to a better understanding of this rare disease.

Keywords: Case report; Central nervous system; Hemangiopericytoma; Metastasis; Pancreas; Solitary fibrous tumor.

Figure 1

Time axis of the patient’s detection, treatment, and post-operative follow-up of brain tumor. A: Brain computed tomography (CT) revealed an 8 cm × 4.7 cm multilobulated heterogeneous mass at both parieto-occipital lobe; B: Brain CT after osteoplastic craniotomy for removal; C: 16 mo later, brain magnetic resonance imaging (MRI) showed 1.7 cm enhancing lesion at the left cerebellar area which suggested remnant mass; D: 2 years later, brain MRI showed new 0.6 cm sized enhancing mass, suggesting recurrence; E: 5 years later, brain MRI showed multiple masses in both cerebellar area.

Figure 2

Radiologic findings. A: Abdominal computed tomography (CT) showed a 3.5 cm sized mass lesion on the pancreas head; B: The CT scan shows a double duct sign, the dilatation of both the pancreatic duct and bile duct, due to the compression of the mass lesion; C: On magnetic resonance imaging (MRI), T1-weighted imaging showed low signal intensity compared to the surrounding pancreas parenchyma; D: On MRI, T2-weighted imaging showed iso-signal intensity.

Figure 3

Endoscopic ultrasonography findings. A: The mass showed hypoechogenicity inside, leading to an impression of cystic change; B: On doppler mode, blood vessels were observed inside the mass, suggesting it is less likely to be a cystic lesion; C: Endoscopic ultrasonography (EUS)-FNA specimen. H&E staining of the EUS-FNA specimen showed proliferation of spindle to ovoid cells. The specimen stained positive for smooth muscle actin, STAT6, and CD34, but negative for DOG-1, C-kit, S-100, and desmin.

Figure 4

Gross and pathological findings of resected specimens. A: The cut surface of the resected pancreatic specimen showed a 3.9 cm × 3.6 cm well-circumscribed, gray to white-colored mass; B: Resected pancreas specimen. H&E staining of the resected pancreas specimen showed dense spindle to ovoid cells with positivity to CD34, epithelial membrane antigen (EMA), and STAT6 and negativity to desmin, smooth muscle actin, DOG-1, c-kit, and S-100; C: Resected brain specimen. H&E staining of the resected brain specimen showed dense spindle to ovoid cells with positivity to CD34, vimentin, and STAT6 and negativity to S-100, glial fibrillary acidic protein, and EMA. GFAP: Glial fibrillary acidic protein.