Asymptomatic thoracic Pantopaque cyst mimicking an intradural extramedullary lipoma on MR images

Abstract

Intraspinal masses showing metal-like density in X-ray or computed tomography but in MRI showing only lipoma or cystic lesions, not metallic characteristics, the differential diagnosis should include iophendylate (Pantopaque) cyst. Oil-based contrast medium is believed to have the potential to make a syrinx formation via arachnoiditis, which can lead to severe neurologic deteriorations, so even if the patients do not represent with an acute neurologic deficit, surgical total removal of remnant material without leaking should be considered.

Pantopaque contrast mimicking intracanalicular vestibular schwannoma

“…Radiographically, residual Pantopaque on MRI appears hyperintense on T1‐ and T2‐weighted images; however, isointense or hypointense T2‐weighted lesions have also been described . Unlike a schwannoma, Pantopaque droplets typically will not enhance . However, if surrounding fibrosis and inflammation are present, some enhancement may be seen.…”

“…4,[8][9][10] Unlike a schwannoma, Pantopaque droplets typically will not enhance. 5,7 However, if surrounding fibrosis and inflammation are present, some enhancement may be seen. Signal characteristics of remnant Pantopaque are comparable to that of blood or fat with both short T1 and T2 relaxation times; therefore, they may mimic the appearance of hemorrhagic lesions or fatty lesions.…”

“…However, residual contrast media was found to reside in the subarachnoid space due to its extremely low clearance rate, thereby potentially leading to chronic irritation, arachnoid adhesions, severe arachnoiditis, or nerve root irritation . In addition, its presence may mimic other pathologies, such as benign intracranial or spinal tumors, providing a source of diagnostic confusion when evaluating these patients . Pantopaque was replaced by water‐soluble contrast agents and therefore has no longer been used in the United States since the late 1980s.…”

“…[2][3][4] In addition, its presence may mimic other pathologies, such as benign intracranial or spinal tumors, providing a source of diagnostic confusion when evaluating these patients. [5][6][7] Pantopaque was replaced by water-soluble contrast agents and therefore has no longer been used in the United States since the late 1980s. Despite this, complications and sequelae from remnant contrast media may be encountered in clinical practice today, emphasizing the importance of being aware of this entity.…”

White Spots on CT Scan of Brain

“…Because of their adverse effects, oil-based agents became replaced by water-based contrast media (1, 2). Hence, oil-based contrast media-myodil or pantopaque-are absorbed and excreted very slowly from the body; even after years, they can be seen as remnants in imaging studies of the brain or spinal cord, such as CT or MRI (3,4).…”