Neurofibromatosis Type 1: A Diagnostic Mimicker at CT

Abstract

Neurofibromatosis type 1 (NF1) is the most common of the phakomatoses and has a variety of localized or, more frequently, systemic manifestations throughout the thorax, abdomen, pelvis, and extremities. Classic computed tomographic (CT) findings in NF1 with thoracic involvement include small, well-defined subcutaneous neurofibromas, focal thoracic scoliosis, posterior vertebral scalloping, enlarged neural foramina, and characteristic rib abnormalities due to bone dysplasia or erosion from adjacent neurofibromas. However, more atypical manifestations are occasionally seen, and magnetic resonance (MR) imaging can be useful in equivocal cases. NF1 with abdominopelvic involvement tends to arise in the retroperitoneal, mesenteric, and paraspinal regions; it may be quite extensive and therefore difficult to distinguish from adenopathy at CT. The multiplanar capabilities of MR imaging, particularly with T2 weighting, make this modality helpful in evaluating affected patients and making the diagnosis. The classic peripheral manifestations of NF1 include limb hemihypertrophy, pseudarthrosis, peripheral nerve neurofibromas, and subcutaneous common and plexiform neurofibromas. In some cases of NF1, imaging findings are inconclusive, and biopsy and subsequent pathologic analysis are required. Familiarity with the various manifestations of NF1 in different anatomic locations is important in making the diagnosis and optimizing postdiagnostic treatment.

Unilateral absence of sphenoid wing in a Neurofibromatosis type 1 patient: imaging findings

“…The diagnostic criteria consists of café au lait spots, iris hamartomas (Lisch nodules), axillary freckling, bone dysplasia, affected first degree relatives, and multiple central nervous system tumors such as optic nerve gliomas, neurofibromas, and plexiform neurofibromas. Occasionally, neurofibromas are found incidentally at radiological imaging, because affected patients usually have very mild cutaneous symptoms [2,3]. Skeletal abnormalities are scoliosis, sphenoid wing dysplasia, bony distortion and local cystic or erosive change.…”

“…Clinically, sphenoid bone abnormalities cause soft tissue and orbital abnormalities such as exophtalmus, ptosis. Awareness of this process prevent further investigation and wasting time [1,2].…”

“…Sphenoid dysplasia occurs in 5-10% of cases with NF-1 and absence of a sphenoid wing is very rare. Furthermore, sphenoid wing abnormalities is often considered pathognomonic for NF-1 [1,2]. We report a rare case of NF-1 with unilateral absence of sphenoid wing and findings of multi-detector computed tomography (MDCT) and magnetic resonance imaging (MRI).…”

Multimodal Imaging in Neurofibromatosis Type 1-associated Nerve Sheath Tumors

“…After contrast medium is administered, many peripheral nerve sheath tumors exhibit an inhomogenous contrast enhancement, which is due not only to cystic areas, but also to regions of differing cellularity and collagen density [49]. The contrast enhancement and the inhomogeneous nature thereof do not allow reliable differentiation of benign plexiform and malignant tumors [49,50]. Contrast-enhanced CT is widely used for NF1 in the process of tumor staging, particularly in conjunction with 18 F-FDG PET/CT.…”

INTERACTIVE CASE REPORT: Neurofibromatosis Type 1 and Lung Issues: A Case Report

“…Apikal yerleşimli nörofibromlar Pancoast tümörü ile karı-şabilen semptomlara yol açabilir, fakat malign dönü-şüm %2-16 olarak bildirilmiştir. (9)(10)(11). Bizim olgumuzda da ciltteki nörofibromlar dışında akciğerde paravertebral yerleşimli ve 1997 yılından beri büyüme gözlenmeyen nörofibroma ile uyumlu lezyon mevcuttu.…”