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 NF^1,2 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

References

1. Basile U1, Cavallaro G, Polistena A and et al. Gastrointestinal and retroperitoneal manifestations of type 1 neurofibromatosis. J Gastrointest Surg. 2010;14:186-94.

2. Friedman JM. Neurofibromatosis 1: Clinical manifestations and diagnostic criteria. J Child Neurol. 2002;17:548-54; discussion 571- 2, 646-51.

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.