Neurofibromas are benign nerve sheath tumours which were first described by Smith in 1849 and later by von Recklinghausen in 1882 [2
]. They are relatively common tumours with an equal incidence in both sexes and can occur at any age. The majority of neurofibromas are solitary lesions that occur in the dermis or subcutis and are evenly distributed over the body surface [3
]. Their presence in the skin is more common than in the deeper soft tissues. Those occurring below the skin are usually in an axial distribution [4
]. They are slow growing and the majority painless.
Clinically, several forms of neurofibroma are seen, including plexiform neurofibromas, diffuse neurofibromas and visceral neurofibromas. Solitary neurofibromas of the breast are rare, even in women where only four cases have been reported [2
]. In the male breast, there has been only one previous case [1
]. This excludes the occurrence of neurofibromas in the presence of neurofibromatosis (von Recklinghausen's disease) which is regarded as a separate disease process.
Macroscopically, neurofibromas are well circumscribed and if still confined by the epineurium are encapsulated. Most are not encapsulated. They vary in size and shape but most are between 1 cm and 2 cm [7
]. Typically they are white-grey tumours as in the current case, but some are brown. They may be polypoid or fusiform in shape [7
Histologically neurofibromas contain interlacing bundles of elongated cells with wavy, dark staining nuclei and slender cytoplasmic processes [3
These cells are arranged closely and are separated by small amounts of mucoid material. Neurofibromas lack epithelial elements. They demonstrate S-100 positivity, typically in some but not all of their component spindle cells. In keeping with their benign behaviour they lack significant mitotic activity.
In present case mammograms demonstrated a homogeneous mass with a regular, well-demarcated border. There was no calcification or distortion of the surrounding breast architecture. These findings are as expected for a benign lesion of the breast. The mammographic characteristics of male breast cancer and their differences to gynaecomastia are well documented [9
The primary differential diagnosis for this tumour is a neurilemmoma but fibroadenoma, phyllodes tumour, malignant peripheral nerve sheath tumour and myofibroblastoma should all be considered. Neurilemmomas may be differentiated from neurofibromas by the presence of Antoni A and B areas, Verocay bodies and uniform staining for S-100 protein [7
]. All these features were lacking in the current case.
Treatment of neurofibromas is by surgical excision. Care should be taken in placing the incision and an inferior periareolar incision is preferred [10
]. Solitary neurofibromas in general are associated with a low local recurrence rate if completely excised [7
]. In none of the previously reported cases of a neurofibroma in the breast, has recurrence occurred.