Kashif Siddique ( Shaukat Khanam Memorial Cancer Hospital, Lahore, Pakistan )
Zeeshan Shabeer Sipra ( Shaukat Khanam Memorial Cancer Hospital, Lahore, Pakistan )
Periportal Plexiform Neurofibromatosis (PPNF) is a rare visceral manifestation of Neurofibromatosis Type 1 (NF1) or Von Recklinghausen disease. Neurofibromas are the most common lesions in NF1. We present a case of a young female diagnosed with NF1 who initially presented with hard abdominal mass. Contrast enhanced CT revealed the unusual lintrahepatic periportal plexiform neurofibromatosis in addition to a typical large retroperitoneal lumbar neurofibroma.
Keywords: Periportal neurofibromatosis, porta hepatis, neurofibroma , NF1.
A young female with past medical history of paraplegia, presented with a hard abdominal mass. Contrast enhanced CT scan was performed which revealed a classical large retroperitoneal neurofibroma [Figure-1].
In addition to that, a low attenuating, hypo enhancing mass was noted within the porta hepatis encasing the portal vein, hepatic artery and its branches and biliary radical with marked intrahepatic periportal infiltration [Figure-2. (a)(b)] but without any vascular compression or biliary dilatation.
People with NF1 develop multiple benign localized or plexiform neurofibromas anywhere in the body. Abdominal involvement is rare (10-25%) and mainly affects the small bowel, retroperitoneum and less frequently the colon.1 Plexiform neurofibroma of porta hepatis extending into liver along portal venous tree is a further rarely reported manifestation. Plexiform neurofibroma, a highly pathognomonic feature of NF1,2 is a complex and disordered mass formed of fusiform, rope like expansion of multiple nerve fascicles. On CT, plexiform neurofibromas are visualized as multilobulated low-attenuation masses, usually within a major nerve distribution. In PPNF, the non-enhancing low-attenuation lesions surrounding central and peripheral periportal spaces have been described as the "periportal collar sign".3 On MRI, the target sign has been described as being nearly pathognomonic of neurofibroma on T2-weighted MR images and consists of low-to-intermediate signal intensity centrally with a ring of high signal intensity peripherally.4
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3. Rodríguez E, Pombo F, Rodríguez I, et al. Diffuse intrahepatic periportal plexiform neurofibroma. Eur J Radiol. 1993;16:151-3.
4. Lin J, Martel W. Cross-sectional imaging of peripheral nerve sheath tumors: characteristic signs on CT, MR imaging, and sonography. AJR Am J Roentgenol.2001;176:75-82.