Fibroepithelial Lesions in the Breast of Adolescent Females: A Clinicopathological Study of 54 Cases

Abstract

Background Fibroepithelial lesions (FELs) are the most frequent breast tumors in adolescent females. The pubertal hormonal surge could impact the growth and microscopic appearance of FELs in this age group. In this study, we evaluate the morphology and clinical behavior of FELs in adolescents. Design We searched the 1992–2012 pathology database for FELs in females 18 years old or younger (F≤18y). Seven FELs from 1975–83 were also included. Three pathologists reviewed all available material. Patient (pt) characteristics and follow-up information were obtained from electronic medical records. Results Forty-eight F≤18y had 54 FELs with available slides. Thirty (67%) pts were Caucasian, 12 (27%) African-American, two (4%) Hispanic, one (2%) Asian; three were of unknown race/ethnicity. Median age at diagnosis was 16 y. Median age at menarche was 12 y; most (96%) FELs occurred after menarche (median interval 48 months). All pts underwent lumpectomy; one required subsequent mastectomy. The FELs were 34 fibroadenomas (FAs) (11 usual, 23 juvenile), and 20 phyllodes tumors (PTs) (16 benign, one borderline and three malignant). Eight (35%) juvenile FAs showed slight intratumoral heterogeneity. The mean mitotic rate was 1.3 mitoses/10 high-power fields (HPFs) (range, 0–6) in usual FAs, 1.8/10 HPFs in juvenile FAs, 3.1/10 HPFs in benign PTs, 10/10 HPFs in the borderline PT and 17/10 HPFs in malignant PTs. The mean follow-up for 29 pts with 33 FELs was 44 months. Two (10%) PTs recurred locally (a benign PT at 18 months, and a borderline PT at 11 months). Both recurrent PTs had microscopic margins <1 mm. Conclusion Mitotic activity in FAs from adolescents can be substantial and this finding should be interpreted cautiously. Awareness of the morphologic features of FELs in adolescents is important to avoid overdiagnosis of PTs, which can lead to additional unnecessary and potentially disfiguring surgery.

Fibroepithelial lesions of the breast: a comprehensive morphological and outcome analysis of a large series

“…We noticed that the most mitotically active area is often only focal, confined to a single set of 10 HPF, especially in the low end of the spectrum. Increased mitotic index in fibroepithelial lesions has been described in pediatric and adolescent populations [21,22]. We also found that patients with fibroadenomas and benign phyllodes that had mitotic index outside of the expected range tended to be younger (the mean and median age of 30 years).…”

Molecular insights into paediatric breast fibroepithelial tumours

“…Interestingly, although fibroadenomas with a higher stromal mitotic count may be associated with an increased risk of recurrence, some studies have found conversely that phyllodes tumours with MED12 mutations have a lower risk of recurrence . Also, another study reported that stromal mitotic activity in paediatric fibroadenomas can be substantial, ranging up to seven per 10 high‐power fields, and caution against overdiagnosing phyllodes tumours …”

“…6,27,28 Also, another study reported that stromal mitotic activity in paediatric fibroadenomas can be substantial, ranging up to seven per 10 high-power fields, and caution against overdiagnosing phyllodes tumours. 29 One limitation of our study is that the stromal component of the fibroadenomas was not microdissected from the epithelial component before sending for targeted gene sequencing. As a result, the gene mutations that were found may not be entirely attributable to the stromal component of the tumour alone and could be possibly localised to the epithelium.…”

Surgical management of giant juvenile fibroadenoma with skin reducing tumor resection and immediate breast reconstruction: A single‐center experience

“…However, phyllodes tumors share similar histological fashion with fibroadenomas, sometimes surgeons have to do needle biopsy to preclude malignant phyllodes tumor, which requires a wider excision than fibroadenomas. Though Ross et al hold the view that morphologic features of fibroepithelial lesions should be diagnosed cautiously in adolescents, especially to avoid over diagnosis of phyllodes tumor, which might lead to unnecessary and potentially disfiguring surgery. On the other hand, a review of malignant breast cancer in children reported that most childhood phyllodes tumors are benign .…”

“…In addition, no treatment guidance was provided for GJF. In some previous reports, the patients were treated with only simple surgical resection alone, as referenced by Sosin et al breast reconstruction was completed in 27 out of 153 cases (17.6%) . However, considering the removal of a large fibroadenoma (more than 2000 g) may significantly affect the shape of the breast, it is necessary to perform immediate or delayed breast reconstruction.…”