Granular cell tumor of the breast mimicking malignancy: a case report with a literature review

Granular cell tumour of the breast

Granular cell tumours (GCT) of the breast have similar clinical and radiological features to breast carcinomas. We present a case of a female patient with a tender, palpable lump, and associated skin changes. Imaging of the lesion was suspicious of malignancy. Initial histological examination showed uniform sheets of polygonal cells with abundant granular cytoplasm, and follow-up immunohistochemistry showed strongly positive staining of tumour cells with S100 and CD68, confirming the diagnosis of GCT. Wide local excision with complete resection margins was performed as a curative treatment for this lesion. This case report highlights the importance of considering GCTs in the differential diagnoses of breast lesions suspicious of malignancy and emphasises the necessity of accurate diagnosis of GCT for proper treatment.

Case Report of a Benign Granular Cell Tumor Resembling Breast Carcinoma in a Young Woman: A Diagnostic Challenge

Introduction

Granular cell tumors (GCTs) are uncommon, low-grade Schwann cell tumors found in the skin, soft tissue, and mucosal surfaces of the oral, gastrointestinal, and respiratory tracts. One in 1,000 breast cancer cases is GCT. Just 1-2% of GCTs are malignant GCTs.

Case Presentation

This case report presents the clinical details and outcomes of a 34-year-old woman with a main concern of a palpable mass and pain in her right breast. In the clinical examination, we found a 1.5 × 2-cm palpable mass in her right breast with no axillary lymph node detection. The primary diagnosis was a benign GCT mimicking carcinoma of the breast. Upon evaluation, the mass was confirmed to be a benign GCT through pathology. The patient underwent breast-conserving surgery and sentinel lymph node dissection at the Cancer Research Center of Shahid Beheshti University of Medical Sciences on November 30, 2022. The surgical margins were found to be free of tumors, and there was no involvement of skin or axillary lymph nodes. The patient had a positive postoperative outcome, with no complications observed.

Conclusion

The case highlights the importance of accurate diagnosis and appropriate surgical planning to avoid invasive procedures and unnecessary radical surgeries in cases of benign GCT mimicking carcinoma of the breast.

Uncommon Tumors and Uncommon Presentations of Cancer in the Breast

Purpose of review

The purpose is to present a case series of rare diagnoses and unusual presentations of breast lesions with radiologic-pathologic correlation from a major cancer center, and to review the recent literature on each entity with a focus on radiology-pathology concordance. We present our findings and experience from cases of metastatic small cell lung carcinoma to the breast, IgG-4 related breast disease, breast implant associated anaplastic large cell lymphoma, granular cell tumor, pleomorphic sarcoma, adenomyoepithelioma, post-radiation angiosarcoma, and breast carcinoma after risk-reducing total mastectomy.

Recent findings

It is essential for physicians to have knowledge of rare breast diagnoses and unusual breast disease presentations to formulate a complete differential diagnosis, recognize radiological-pathological concordance of these entities and provide appropriate patient care.

Summary

Current literature on these rare described entities exists mainly as case reports, case series and small-scale studies. By sharing our findings, we hope to educate trainees in radiology, pathology and other fields across the continuum of care in radiologic-pathologic correlation, while also augmenting the existing literature on these rare entities.

Granular cell tumor of the breast: correlations between imaging and pathology findings

Objective

To review the imaging features of granular cell tumors of the breast (on mammography, ultrasound, and magnetic resonance imaging), establishing a pathological correlation, in order to familiarize radiologists with this entity and make them aware of the differential diagnoses, other than malignancy, of lesions with spiculated margins.

Materials and Methods

We reviewed the medical records (from a clinical-pathology database and picture archiving and communication system) of five patients with a pathologically confirmed diagnosis of granular cell tumor of the breast, treated at the Portuguese Oncology Institute of Lisbon, in the city of Lisbon, Portugal, between January 2012 and December 2018.

Results

All five tumors exhibited imaging features highly suggestive of malignancy (BI-RADS 5 lesions), namely spiculated margins, significant depth, and posterior acoustic shadowing (on ultrasound). One tumor showed a kinetic curve indicative of washout on magnetic resonance imaging, two were adherent to the pectoralis muscle, and one was accompanied by skin retraction. Pathology provided the definitive diagnosis in all cases.

Conclusion

Granular cell tumors of the breast pose a diagnostic challenge because they can present with clinical and imaging features mimicking malignancy, and the diagnosis is therefore provided by pathology. Radiologists should be familiarized with this entity, so they can be aware of the fact that breast lesions with spiculated margins can be indicative of diagnoses other than malignancy.