British Journal of Radiology (2007) 80, e234-e237
© 2007 British Institute of Radiology
doi: 10.1259/bjr/33539044
Myxoid neurofibromas of the breast: mammographical, sonographical and MRI appearances
G Gokalp, MD
1,2
B Hakyemez, MD
1
E Kizilkaya, MD
2 and
A Haholu, MD, PhD
3
1 Department of Radiology, Uludag University Medical School, Gorukle, Bursa and Departments of, 2 Radiology, 3 Pathology, GATA Haydarpa
a Training Hospital, Uskudar, Istanbul, Turkey
Correspondence: Gokhan Gokalp, Uludag University School of Medicine, Gorukle, Bursa, Turkey. E-mail: drgokhangokalp{at}yahoo.com
 |
Abstract
|
|---|
Neurofibromas arise from elements in the peripheral nervous system and are rarely detected in the breast. Neurofibromatosis is a phakomatosis that displays a wide spectrum of clinical expression with neurocutaneous abnormalities and involvement of multiple organ systems. Neurofibromas are more common in neurofibromatosis Type 1. They can show variable amounts of myxoid change, which affect their radiological findings. In this paper, we present a patient with neurofibromatosis Type 1 with mammographical, sonographical and MRI findings of myxoid neurofibromas in her left breast.
|
Introduction
|
|---|
Neurofibromas are common benign tumours of perineural cell origin that arise from elements in the peripheral nervous system [1]. Variable amounts of myxoid (mucoid) change often accompany benign and malignant peripheral nerve tumours [2]. The vast majority occur in the skin and are very rare in breast tissue itself [1–5]. Neurofibromatosis is a phakomatosis that displays a wide spectrum of clinical expression with neurocutaneous abnormalities and involvement of multiple organ systems [6]. There are two major forms, designated neurofibromatosis Type 1 (NF1) and neurofibromatosis Type 2 (NF2), which are clinically and genetically distinct. NF1 is commonly associated with peripheral nerve sheath tumours, whereas NF2 primarily affects the central nervous system. The diagnosis of NF1 is largely based on clinical criteria established by the National Institutes of Health Consensus Development Conference [6–8]. The most common clinical manifestations are six or more café au lait spots, two or more neurofibromas, two or more Lisch nodules, axillary or inguinal freckling, sphenoid wing dysplasia or thinning of a long bone cortex and optic glioma. Two or more of the criteria are required for diagnosis [1, 6]. We report a rare case of a 46-year-old woman with NF1 who has myxoid neurofibromas in her left breast.
|
Case report
|
|---|
A 46-year-old woman with an approximately 20-year history of NF1 applied for screening mammography. Clinical examination revealed multiple café au lait spots, subcutaneous neurofibromas, axillary/inguinal freckling and hamartomas of the iris (Lisch nodules). Apart from the subcutaneous neurofibromas, there were no associated neurological findings and she had no family history. The mammograms revealed a few non-calcified, oval lesions with smooth and partially obscured margins forming lobulations of cutaneous tissue and asymmetric enlargement of the left breast (Figure 1
). Sonography demonstrated well-defined, hypoechoic, oval lesions (Figure 2) with mild posterior acoustic enhancement (Breast Imaging and Reporting Data System (BI-RADS) category 3). Dynamic breast MRI revealed five well-defined masses in the left breast. All of the masses demonstrated low signal intensity on T1 weighted MR images (Figure 3a) and high signal intensity on T2 weighted MRI (Figure 3b) compared with fat tissue. After administration of contrast material, the time–signal intensity curves were formed and two patterns were revealed: non-enhancement and gradual enhancement. Only one mass showed homogeneous contrast enhancement on post-contrast MR images (Figure 3c). Initial enhancement (first 3 min) was more than 100%. Type 1 curves (progressive or gradual enhancement) showed continuity of signal intensity with time (Figure 3d). Morphological characteristics and enhancement patterns of the lesions on MR images suggested benignity. Core needle biopsy of the enhancing mass revealed myxoid neurofibroma. Another core needle biopsy of the biggest non-enhancing mass in the breast also revealed the same diagnosis (Figure 4). The right breast of the patient was normal both sonographically and on MR images.
View larger version (122K):
[in this window]
[in a new window]
|
Figure 1. Craniocaudal mammogram showing a few non-calcified, oval masses partly obscured by surrounding fibroglandular breast tissue in the left breast. Masses cause lobulations of cutaneous tissue and asymmetrical enlargement of the breast.
|
|
View larger version (132K):
[in this window]
[in a new window]
|
Figure 2. Sonography demonstrating well-defined, oval, hypoechoic, solid masses with slight posterior acoustic enhancement within the left breast.
|
|
View larger version (86K):
[in this window]
[in a new window]
|
Figure 3. Dynamic breast MRI.(a) Sagittal pre-contrast three-dimensional T1 weighted fast low-angle shot (FLASH) sequence showing a low intensity, oval, well-defined mass (arrow). (b) Axial T2 weighted fast spin-echo image showing a high intensity mass (arrow). (c) Subtraction of the post-contrast from the pre-contrast image displays a homogeneously enhancing lesion. (d) The signal-to-time curve in this enhanced mass reveals a strong initial signal intensity increase of more than 100% in the first 3 min, followed by a gradual enhancement in the next few minutes (Type 1 curve).
|
|
View larger version (49K):
[in this window]
[in a new window]
|
Figure 4. (a) The histological appearance (x10; H&E stain) of a neurofibroma reveals proliferation of nerve fibres and fibroblasts beneath the covering epidermis of breast skin. (b) Magnification of the same area (x20; H&E stain) shows cells dispersing in loose, disordered myxoid stroma.
|
|
|
Discussion
|
|---|
NF1 is the most common type of phakomatosis and occurs with an incidence of one case per 3000 live births. NF1 is inherited as an autosomal dominant disorder; however, up to 50% of cases occur sporadically as a result of spontaneous mutation [6, 7]. The NF1 gene is located in the pericentromeric region of the long arm of chromosome 17. The extremely large size of the gene is consistent with the high spontaneous mutation rate of neurofibromatosis (
50%). Mutations in the NF1 gene lead to abnormal tumour suppression and an increased prevalence of benign and malignant neoplasms throughout the body [9]. The clinical expression of NF1 is variable. NF1 symptoms are mild in many patients. The major tumour types observed in NF1 are gliomas, malignant peripheral nerve sheath tumours, leukaemia, rhabdomyosarcoma, cystosarcoma phylloides and breast cancer [10]. The classic neurogenic tumours occurring outside the central nervous system include neurofibromas.
Peripheral nerve sheath tumours are divided into two major benign categories, neurofibroma and schwannoma, and a malignant form, malignant peripheral nerve sheath tumour. Each category can be associated with neurofibromatosis [10]. Although major nerve trunks are most commonly affected, virtually any peripheral nerve can represent a site of origin. Breast involvement is rather uncommon and, when present, tumours are most commonly found in the areolar area [1–5]. In our patient, however, there were multiple lesions not only in the areolar area but also in the other quadrants.
Neurofibromas, which are not encapsulated, are common tumours that arise from elements in the peripheral nervous system. Pathologically, neurofibromas in NF1 can be divided into three types: localized, plexiform and diffuse [6]. As in our patient, localized intraneural neurofibromas are confined to the affected nerve. They are composed of Schwann cells and fibroblasts and are accompanied by variable amounts of myxoid change. Myxoid tumours demonstrate significant differences in biological behaviour, ranging from completely harmless to malignant neoplasms [6]. The incidence of sarcomatous change of neurofibromas varies from 5% to 15% [7].
Neurofibromas are oval or round in shape with circumscribed margins on mammography and sonography. Sonography shows a hypoechoic lesion and may show distal acoustic enhancement, as in our patient, resembling a cyst and causing misdiagnosis. This effect has also been described with other solid tumours of uniform cellularity, such as lymphoma, which affects the lymph nodes [9–11].
The MRI features of breast neurofibromas are not documented in the English language literature. MRI findings depend largely on the histopathological characteristics of the tumour. Neurofibromas show low to intermediate signal intensity on T1 weighted images and heterogeneous signal intensity on T2 weighted images. The hyperintense regions on T2 weighted images correspond to areas of cystic degeneration or myxoid matrix, whereas the hypointense regions represent collagen and fibrous tissue. Hypointense areas on T2 weighted images may enhance following gadolinium administration [6, 7]. In our patient, myxoid changes, also shown histopathologically, were responsible for high signal intensity on T2 weighted images and showed a benign enhancement pattern. Four of the lesions did not enhance after contrast enhancement. A malignant contrast enhancement pattern is an expected finding in neurofibromas with sarcomatous changes, as in other malignant tumours. Breast MRI can aid in demonstrating enhancing lesions before biopsy and in predicting a pathological diagnosis.
In summary, neurofibromas, which are rare tumours of the breast, have different radiological appearances depending on their histopathological characteristics. Sonography may show posterior acoustic enhancement, simulating a cyst. If the tumour has myxoid matrix, it shows high signal intensity on T2 weighted images. Either non-enhancement or gradual enhancement following contrast material injection may also be demonstrated on MR imaging.
Received for publication March 5, 2007.
Revision received June 7, 2007.
Accepted for publication June 25, 2007.
|
References
|
|---|
- Murat A, Kansiz F, Kabakus N, Kazez A, Ozercan R. Neurofibroma of the breast in a boy with neurofibromatosis type 1. Clin Imaging 2004;28:415–7.[CrossRef][Medline]
- Wakely PE Jr. Myxomatous soft tissue tumors. Correlation of cytopathology and histopathology. Ann Diagn Pathol 1999;3:227–42.[CrossRef][Medline]
- Millman SL, Mercado CL. An unusual presentation of neurofibromatosis of the breast. Breast J 2004;10:45–7.[CrossRef][Medline]
- Sherman JE, Smith JW. Neurofibromas of the breast and nipple areolar area. Ann Plast Surg 1981;7:302–7.[CrossRef][Medline]
- Fink D, Schneider C, Wight E, Perucchini D, Haller U. Neurofibromatosis of the breast in a patient with morbus von Recklinghausen. Gynakol Geburtshilfliche Rundsch 2000;40:47–9.[CrossRef][Medline]
- Levy AD, Patel N, Dow N, Abbott RM, Miettinen M, Sobin LH. Abdominal neoplasms in patients with neurofibromatosis type 1: radiologic-pathologic correlation1. RadioGraphics 2005;25:455–80.[Abstract/Free Full Text]
- Fortman BJ, Kuszyk BS, Urban BA, Fishman EK. Neurofibromatosis type 1: a diagnostic mimicker at CT. RadioGraphics 2001;21:601–12.[Abstract/Free Full Text]
- Gutmann DH, Aylsworth A, Carey JC, Korf B, Marks J, Pyeritz RE, et al. The diagnostic evaluation and multidisciplinary management of neurofibromatosis 1 and neurofibromatosis 2. JAMA 1997;278:51–7.[Abstract/Free Full Text]
- Guran S, Safali M. A case of neurofibromatosis and breast cancer: loss of heterozygosity of NF1 in breast cancer. Cancer Genet Cytogenet 2005;156:86–8.[CrossRef][Medline]
- Lin J, Martel W. Cross-sectional imaging of peripheral nerve sheath tumors: characteristic signs on CT, MR imaging, and sonography. AJR 2001;176:75–82.[Free Full Text]
- Reynolds DL, Jacobson JA, Inampudi P, Jamadar DA, Ebrahim FS, Hayes CW. Sonographic characteristics of peripheral nerve sheath tumors. AJR 2004;182:741–4.[Abstract/Free Full Text]
Top
Abstract
Introduction
