Neurofibroma in the Breast: Diagnosis and Management Considerations

Abstract

Neurofibroma (NF) of the breast is an uncommon benign entity that occurs sporadically or in association with neurofibromatosis type 1 (NF1). Sporadic NF of the breast is very rare and can present at any age. Neurofibroma of the breast associated with NF1 is more common. Neurofibroma commonly presents as oval, circumscribed masses that overlap with many benign entities. The histopathologic diagnosis of NF of the breast can present a management dilemma for the breast radiologist. An NF that is not associated with NF1 has good post-resection prognosis if superficial, sporadic, and solitary. However, NF of the breast diagnosed in an otherwise healthy patient should prompt evaluation for NF1 and formal genetic risk assessment. Patients diagnosed with NF1 have a higher lifetime risk for developing breast cancer and therefore may benefit from both initiating screening mammography at a younger age and supplemental screening MRI.

Mesenchymal Tumors of the Breast: Fibroblastic/Myofibroblastic Lesions and Other Lesions

“…Lesions can be associated with neurofibromatosis type 1 (NF1, aka von Recklinghausen disease), an autosomal dominant genetic disorder. Most lesions (90%) are sporadic but also tend to have intra-lesions NF1 mutations [77,78]. Most neurofibromas affect the head, neck, and extremities, with only a few case reports of mammary neurofibromas in the absence of NF1 [75,79].…”

“…Sporadic neurofibromas tend to occur in the third or fourth decade of life without gender predilection [28,78] as solitary, slow-growing, and painless lesions in superficial tissues. In the breast, there is a predilection for the NAC or the pectoralis fascia [78]. There are three described subtypes; two can be found in the breast, as listed below.…”

“…Localized: Localized neurofibromas account for 90% of these lesions [78,79,81]. Clinically, they are lobular skin-colored lesions with pathognomonic "button-hole sign [81]".…”

“…Sonographically, localized lesions appear as superficial, circumscribed nodules that are hypoechoic and resemble cysts [79] or fibroadenomas [78]. Diffuse lesions can appear hyperechoic, containing multiple interconnected hypoechoic tubular structures and lesion extent is often difficult to determine [81].…”

“…Diffuse lesions can appear hyperechoic, containing multiple interconnected hypoechoic tubular structures and lesion extent is often difficult to determine [81]. Mammographically, they are hyperdense, wellcircumscribed lesions that can be missed given their propensity to occur posteriorly (retroglandular fat or pectoralis fascia) [78]. On MRI, neurofibromas are hypo-or iso-intense on T1 and hyperintense and heterogenous on T2 with lack of or gradual enhancement [75].…”