Cholesterol Granuloma of the Breast Mimicking Cancer: A Case Report and Review of the Literature

Abstract

Cholesterol granuloma of the breast is an infrequent benign lesion with clinical and radiological findings suggestive of cancer. Herein, we present the case of a 52-year-old woman with no significant past medical history, who presented to the outpatient department for her routine breast screening. Physical examination revealed a painless palpable nodule in the upper external quadrant of the left breast, measuring 0.7 cm. On imaging, the mass met the criteria for Breast Imaging Reporting and Data System (BI-RADS) category 4B. Subsequently, a core needle biopsy of the mass was performed. Despite the alarming radiologic features, microscopic findings were consistent with breast cholesterol granuloma.

Introduction

Cholesterol granuloma of the breast (CGB) is an uncommon benign condition usually mistaken for malignancy clinically and on imaging.^1,2 Only a few cases of CGB have been reported in the literature so far.^3,4

Herein, we present the case of a 52-year-old woman with a breast cholesterol granuloma that was clinically and radiologically suspected to be a malignant lesion.

Case Presentation

A 52-year-old woman, who had no significant past medical history, presented to the outpatient department for her routine breast screening. The patient had no history of chest wall trauma or a previous breast biopsy. No family history of breast cancer was given.

Physical examination revealed a painless palpable firm elastic nodule in the upper external quadrant of the left breast, measuring 0.7 cm. There was no axillary lymph node swelling, skin changes, or nipple discharge.

Ultrasonography showed a hypoechoic lesion with irregular margins. Mammography showed a 0.6 cm lesion with high-density and ill-defined margins. No microcalcifications were identified. The mass met the criteria for Breast Imaging Reporting and Data System (BI-RADS) category 4B.

Subsequently, a core needle biopsy of the breast mass was performed.

Microscopically, the lesion consisted of thick cholesterol crystals arranged in parallel or radial arrays with numerous foreign-body multinucleated giant cells. Hemosiderin-laden macrophages were also identified. The adjacent mammary parenchyma showed no ductal ectasia. There was no evidence of malignancy (Figure 1).

Figure 1.

On microscopic examination, the breast lesion consisted of thick cholesterol crystals arranged in parallel or radial arrays. Cholesterol clefts were surrounded by numerous foreign-body multinucleated giant cells (H&E stain, ×100).

Despite the suspicious radiologic appearance, the final diagnosis of the breast mass was mammary gland cholesterol granuloma.

Since the lesion was determined to be benign and there were no symptoms of breast disease, a surgical procedure was not recommended. The patient was planned for regular follow-up and routine breast screening.

Discussion

Cholesterol granuloma is a benign condition that commonly occurs in the mastoid process and the middle ear in association with cholesteatoma.^3,5,6 However, CGB is unusual and rarely reported in the literature.^1,3,4 The disease mimics breast cancer clinically and on imaging.^1,2,4

The mean age of patients is 57.5 years. ⁷ Patients with CGB often present with a painless breast lump.^2,4,5,8 The lesion may also be discovered incidentally during routine breast screening. ² ,^9-12 Physical examination usually reveals a firm mobile nontender mass with no lymphadenopathy or nipple discharge.^3,5,6

Radiological features of CGB are usually indistinguishable from cancer. ¹¹

Ultrasonography often shows an ill-defined, hypoechoic, and heterogeneous mass.^1,3,4,11 Cholesterol granuloma of the breast may also be an intracystic mass mimicking papillary lesions. ⁸ Furthermore, CGB may present as an enlarging mass in the vicinity of a prior breast biopsy. ⁵ Suspicious mammographic findings of CGB include ill-defined margins, high density, irregular shape, and microcalcifications.^2,6,9,11 Annular calcifications were reported in one case. ³

Moreover, Martineau et al ¹³ reported a case of CGB with a focal fluorodeoxyglucose uptake on positron emission tomography–computed tomography imaging, which led to the misinterpretation of the lesion as a malignant neoplasm.

In one case report, Hu et al demonstrated the importance of T1-weighted dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) to distinguish CGB from breast cancer. The DCE-MRI of CGB showed a mild progressive enhancement with a type I (benign) time-signal intensity curve, while DCE-MRI of breast cancer showed rapid, intense enhancement with a type III (malignant) time-signal intensity curve. ¹⁴

Fine needle aspiration of CGB often demonstrates foreign body multinucleated giant cells.^9,11,12 On surgical specimens, the cut surface of CGB may show a concentric ring finger appearance or a gritty texture.^3,11,15 The histological hallmark of CGB is a fibrous granulation tissue containing a large number of cholesterol needle-like crystals arranged in parallel or radial arrays and surrounded by foreign-body multinuclear giant cells.^2-5, ⁹ Hemosiderin and foamy histiocytes may also be seen. ⁴ Moreover, unusual osseous metaplasia was described in one case. ³

The pathogenesis of CGB is not clearly elucidated.^9,13 It is speculated that the disorder is related to mammary duct ectasia associated with periductal inflammation.^1,14 The leakage of lipid-rich contents from damaged walls of ectatic ducts into the periductal parenchyma may lead to the formation of cholesterol crystals with surrounding foreign body–type giant cell reaction and granulomatous inflammation.^9,10,12,14 Besides, it is speculated that CGB may be the unusual result of breast macrocysts rupture. ¹² In addition, it is reported that a history of trauma or breast biopsy may lead to CGB. ⁴

Interestingly, despite the benign nature of this uncommon disorder, concomitant CGB and invasive ductal carcinoma were reported in 2 cases.^4,14

Conclusion

Breast cholesterol granuloma is an infrequent condition with clinical and radiological findings suggestive of cancer. Clinicians and radiologists should keep in mind this benign lesion when considering a suspicious breast lump to avoid unnecessary surgery.