Granular cell tumor of the breast: Molecular pathology and clinical management

Abstract

Granular cell tumor is a rare condition that occasionally affects breast parenchyma: approximately, 5%-15% of all granular cell tumors represent 1:1000 of breast tumors. In this study, we reported a consecutive series of 12 patients with primary granular cell tumor of the breast observed at our institute, focusing attention on preoperative management, surgical approach, and long-term follow-up. Eight cases (8/12; 66.78%) presented with left-breast tumors; in the majority of patients (11/12; 91.7%), the lesion was identified in one of the upper quadrants. Specifically, upper intern quadrants (10 cases) were more affected. Surgical excision was performed in all patients. Mean diameter at pathologic section was 11.4 mm (range: 5-22). Tumor relapse was reported only in one case (8.3%). Mean follow-up was 98.1 months (range: 1-192). We proposed a model to explain the molecular mechanism of granular cell tumorigenesis associating to the high level of S100 protein. Management of primary granular cell tumor of the breast requires a correct initial diagnosis using breast imaging associated with core biopsy. Surgical procedure with wide resection or quadrantectomy requires a careful evaluation of breast margins.

Mammary mesenchymal and fibroepithelial lesions: An illustrated cytomorphologic update with differential diagnoses

“…Other than fibroadenomas, fibroepithelial and mesenchymal lesions of the breast undergo assessment by FNAC far less commonly than epithelial neoplasm. While findings from comparatively large series of uncommon mesenchymal breast tumors, such as myofibroblastomas and granular cell tumors exist in the histology literature, experience with FNAC of mesenchymal breast lesions is typically limited to case reports and small series . The literature on breast FNAC suggests that accurate and specific diagnoses may be rendered in 80% of spindle cell lesions undergoing aspiration biopsy .…”

“…101 with FNAC of mesenchymal breast lesions is typically limited to case reports and small series. 53,72,103,104 The literature on breast FNAC suggests that accurate and specific diagnoses may be rendered in 80% of spindle cell lesions undergoing aspiration biopsy. 6 It is our hope that the current illustrated review will assist interpreters of breast aspiration cytology when uncommon mesenchymal lesions are encountered.…”

Imaging features of granular cell tumor in the breast

“…First, GCTB is likely to be derived from Schwann cells of the supraclavicular nerve and has infiltrative growth, resulting in an irregular subcutaneous tumor with blurry edges on images, but there is no oedema in the rims of the lesion compared with breast cancer. [ 10 ] Second, the homogeneity of GCTB tumor cells leads to a uniform echo/density/signal, unlike the heterogeneity and microcalcification of breast cancer. Third, T2-weighted imaging and diffusion-weighted imaging signals in GCTB are often lower than those in breast carcinoma, while the TIC shape of GCTB is mainly I or II type compared with III type for breast cancer.…”

Rare Mesenchymal Breast Entities that Mimic Malignancy: A Single-institution Experience of a Challenging Diagnosis

“…The differential diagnoses of MFB are broad and include reactive processes and benign neoplasms, such as a solitary fibrous tumor, nodular and proliferative fasciitis, fibromatosis, spindle-cell lipoma, myoepithelioma, and pseudoangiomatous stromal hyperplasia [8,21]. Malignant neoplasms, such as stromal sarcoma, malignant fibrous histiocytoma, and spindle-cell or metaplastic carcinoma, should not be confused with a myofibroblastoma [8,[26][27].…”

“…Sentinel lymph node biopsy is not indicated. No specific adjuvant therapies are suggested; however, long-term follow-up is strongly recommended [27]. Local recurrence may occur after incomplete excision.…”