A review of the literature searching for patients with breast cancer and traumatic neuroma revealed a total of 10 reported cases [4
]. This article presents an additional case with breast cancer of traumatic neuroma occurring in a patient 2 years after mastectomy and reviews the previously reported cases.
Table summarizes the clinical circumstances for the 10 reported cases plus this report of traumatic neuroma after mastectomy for breast cancer. The age of the patients at presentation was variable, ranging from 41 to 68 years. The time between mastectomy and presentation with traumatic neuroma was also variable in these 11 cases (2 to 14 years after mastectomy) and the average was 5.3 years. There was only one patient who had three nodules near the mastectomy scar and all other patients had only one nodule. The diameter of every nodule ranged from 0.4 to 1.0 cm. There were 7 patients whose traumatic neuromas were located near the scar of mastectomy, 2 patients whose traumatic neuromas were located in the subclavian area, one patient whose traumatic neuroma was in the axilla and one patient whose traumatic neuroma was located in the 9 o'clock position in the right chest wall. Eight patients underwent ultrasound examination. Reports showed five cases with well-circumscribed, homogeneous, hypo-echoic subcutaneous nodular lesion and two cases with a poorly defined hypo-echoic nodule with good conduction. The latest report from Kim EY et al showes that it was an oval, circumscribed, hypo-echoic nodule with a partially microlobulated margin [8
]. Two cases in one report didn't mention whether they underwent ultrasound examination or not. Ultrasound examination of the case we present showed that the mass was a well-circumscribed, echo-heterogeneous, subcutaneous nodular lesion, with a diameter of about 0.5 cm.
Clinical datas for reported cases of traumatic neuroma after mastectomy for breast cancer
All of the nodules were painless. All of these cases received excision biopsy of the presenting nodules and made a definite diagnosis by histopathological examination.
Table summarizes the diagnosis and treatment of breast cancer for reported cases. The age at diagnosis of breast cancer was variable, ranging from 33 to 63 years. Four patients' stage was T1N0M0, five patients' stage was T2N0M0, and two patients' stage was T2N1M0. Pathological examination of all the patients was invasive ductal carcinoma of the breast. A majority of patients underwent a radical or modified radical mastectomy (There were two cases of a report did not mention the kind of surgery). Seven patients received chemotherapy (specific chemotherapy regimen and cycles are recorded in the Table). Two patients received radiotherapy and five patients received endocrinotherapy in consideration of their ER and PR status (four patients treated with tamoxifen and one patient treated with aromatase inhibitor).
The diagnosis and treatment of breast cancer for reported cases
Neuromas occurred in patients who have received cancer surgery are not well established in the literature, unlike traumatic neuromas following amputation for benign diseases such as post-cholecystectomy [2
]. A traumatic neuroma is not a true neoplasm. It represents a hyperplastic reponse of the nerve to injury, either direct/indirect trauma or chronic inflammation. Traumatic neuromas show disrupted axons with distal demyelination and Wallerian degeneration, and a tangled mass of Schwannou cells and fibroblasts, all in a dense, collagenous matrix [3
]. Enzinger FM et al [9
] and Murphey M at el [10
] consider that a traumatic neuroma usually presents as a palpable nodule which is caused by a non-neoplastic proliferation of the proximal end of a severed, partially transected or injoured nerve after surgery and it dosen't have any potential malignancy. Although most traumatic neuromas affect peripheral sensory nerves, they could also affect motor sensory nerves and autonomic nervous system [11
]. The most frequent site of traumatic neuroma is at radically dissected neck, followed by upper and lower extremities [12
Benign lesions as traumatic neuromas after mastectomy are more rarely seen. The first reported case was in 2000 and there have been only a total of ten published cases. Two of them resembled granular cell tumours at mastectomy. Sometimes there was pain in tumor sites but all of the post-mastectomy patients in the review were asymptomatic. Hence, a traumatic neuroma after mastectomy is an uncommon entity, but it should be kept in mind because the most critical problem is to distinguish the painless nodule from recurrent breast carcinoma. Assistant examination methods such as ultrasound and computed tomography are valuable to a certain extent. Kim EY et al [8
] suggested that if a color Doppler image shows no increased blood flow, fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET-CT) shows no significant uptake, and the time interval between surgery and the development of new lesion is more than 5 years, one should include traumatic neuromas in the differential diagnosis. Huang LF et al [13
] and Yabuuchi H et al [2
] also suggested that several imaging techniques such as ultrasonographic, computed tomographic, and magnetic resonance imaging features have been used to differentiate traumatic neuroma from recurrent lymphadenopthy after neck dissection. Nevertheless, the final diagnosis can only be confirmed on pathologic examination.