A 67-year-old girl in Japan had a CT scan as a result of docs needed a better have a look at an irregular spot on her lung. The scan turned up one thing no one was searching for: a mass measuring 31 by 23 millimeters, a bit over an inch throughout, in her pancreas.
Its look pointed docs towards a pancreatic neuroendocrine tumor, a kind of progress that may be cancerous. After surgical procedure, the actual reply turned out to be far rarer. It was a schwannoma, a often benign tumor of the sheath that wraps round nerves, and in depth bleeding inside it had made it appear like one thing else.
The case, from gastrointestinal surgeons and a pathologist at Kameda Medical Heart in Kamogawa, Chiba, was revealed on-line Oct. 5, 2026, as a scientific picture report in Oxford Medical Case Studies. The title spells out the twist: a hemorrhagic pancreatic schwannoma mimicking a pancreatic neuroendocrine tumor.
A Mass That Seemed Like One thing Else
On contrast-enhanced CT, the expansion had sharp, well-defined borders. Inside, it regarded patchy, with darker areas blended all through. Its edges picked up extra distinction dye because the scan went on, and some small spots inside lit up about as brightly as close by blood vessels.
That image matches a pancreatic neuroendocrine tumor, or pNET, a progress that arises from the hormone-producing cells of the pancreas. The Nationwide Most cancers Institute describes these tumors as unusual cancers, with about 1,000 new circumstances a yr in the US, accounting for lower than 2% of pancreatic malignancies.
The report doesn’t describe any signs tied to the mass. The lady got here to medical consideration solely due to the lung discovering, and the authors didn’t say what that lung spot turned out to be.
Ruling Out the Normal Suspects
Earlier than working, the group ran two specialised nuclear drugs scans to slim the chances. A somatostatin receptor scan, which regularly lights up neuroendocrine tumors as a result of many carry receptors for the hormone somatostatin, got here again adverse.
That consequence helps however doesn’t settle the matter. The Nationwide Most cancers Institute notes that this kind of scan is much less helpful for locating insulinomas, a pNET subtype that always has few of these receptors.
The second take a look at, a scan utilizing a tracer referred to as MIBG, confirmed solely faint uptake. The NCI describes the MIBG scan as a software for locating neuroendocrine tumors corresponding to paragangliomas, a few of which launch extra adrenaline and noradrenaline. After an endocrinology session, a hormone-producing paraganglioma was thought of unlikely.
Collectively, the scans made each pNET and paraganglioma much less probably, however they didn’t present a agency analysis. The surgeons went forward with laparoscopic enucleation, a minimally invasive operation that removes the tumor itself whereas sparing the encircling pancreas.
The Microscope Delivered the Actual Analysis
As soon as the tumor was out, the reason grew to become clear. The well-defined mass contained in depth inside bleeding and degeneration. Below the microscope, pathologists noticed wavy, spindle-shaped cells organized in alternating dense and free patterns, referred to as Antoni A and Antoni B areas, a traditional signature of schwannoma. The cells confirmed no important atypia or indicators of speedy division.
Particular stains confirmed it. The tumor examined optimistic for S100, a protein present in Schwann cells, and adverse for synaptophysin, chromogranin A, and INSM1, markers generally used to establish neuroendocrine tumors.
Schwannomas develop from Schwann cells, which type the protecting sheath round nerves. Mayo Clinic describes schwannoma as the most typical kind of benign peripheral nerve tumor in adults and notes that these tumors are not often cancerous.
The lady recovered with out problems and went residence seven days after the operation.
Why a Uncommon Tumor Is Straightforward to Mistake
Within the pancreas, schwannoma is a real outlier. The authors name it a particularly uncommon tumor, accounting for about 0.03% of all pancreatic tumors.
That rarity is a part of the diagnostic entice. The authors wrote that “the preoperative analysis of PS is difficult as a result of it regularly mimics different pancreatic neoplasms,” utilizing PS as shorthand for pancreatic schwannoma. They pointed to a 2019 assessment by Zhang and colleagues within the journal Pancreatology, which reported that 29% of sufferers with pancreatic schwannoma had been identified with a pNET earlier than surgical procedure.
The authors defined the mix-up on this case this fashion: schwannomas can bleed or type fluid-filled cysts as they degenerate, whereas pNETs can include areas of useless tissue. On this girl’s tumor, the heavy inside bleeding produced an uneven look that resembled a pNET with useless tissue at its core.
One case can solely present a lot. This can be a single affected person described in a brief image-focused report, and it doesn’t set up how typically bleeding leads docs to misinterpret schwannomas or how imaging observe ought to change. What it does present is why analyzing the tissue after elimination can stay the ultimate phrase for some pancreatic plenty, even after superior scans.
For readers, the takeaway is just not {that a} pancreatic mass is more likely to be innocent. Pancreatic growths have many potential causes, a few of them severe, and the correct workup relies on every affected person. Anybody instructed about an surprising discovering on a scan ought to ask their clinician what it would imply and what follow-up is smart.
Key Questions Answered
How was the pancreatic mass found? By likelihood. The 67-year-old girl had a CT scan to guage an irregular lung opacity, and the pictures additionally confirmed a 31-by-23-millimeter mass in her pancreas.
What did the tumor develop into? A pancreatic schwannoma, a tumor that arises from the Schwann cells that sheathe nerves. Pathologists confirmed it via its traditional cell patterns and a optimistic S100 stain, whereas neuroendocrine markers have been adverse.
Why did docs first suspect a neuroendocrine tumor? In depth bleeding contained in the tumor gave it a patchy, uneven look on CT, with enhancement round its edges. The authors mentioned this resembled a pancreatic neuroendocrine tumor with inside necrosis, or useless tissue.
Are schwannomas cancerous? Not often, in response to Mayo Clinic, which calls schwannoma the most typical kind of benign peripheral nerve tumor in adults. Discovering one within the pancreas, nonetheless, is extraordinarily uncommon.
How was the girl handled, and the way did she do? Surgeons eliminated the tumor via laparoscopic enucleation, which spares the remainder of the pancreas. She had no problems and was discharged seven days after surgical procedure.
Does this imply an surprising pancreatic mass might be innocent? No. That is one uncommon case, and pancreatic plenty have many potential causes, a few of them severe. Anybody with an incidental discovering ought to talk about subsequent steps with their clinician.
Printed by Medicaldaily.com
