Idiopathic granulomatous mastitis: A challenging case report and comprehensive review of the literature

Abstract

Introduction and importance

Idiopathic granulomatous mastitis is an uncommon, long-lasting inflammatory condition of the female breast. It is characterized by the development of a painful breast mass that gradually increases in size. This condition is benign and its cause is unknown. It primarily affects women of childbearing age who have a history of pregnancy and breastfeeding. The main feature of idiopathic granulomatous mastitis is the presence of chronic inflammation in the breast.

Case presentation

We report a 36-year-old woman with a history of pregnancy and breastfeeding presented with pain and swelling of the right breast. Physical examination revealed a mass with redness and retraction of the nipple. Imaging revealed localized density and hypoechoic areas with collection, suggesting granulomatous mastitis. A biopsy confirmed the diagnosis. The abscess was drained through a small incision performed under local anesthesia. Treatment with corticosteroids resulted in significant improvement, with complete resolution after one month.

Clinical discussion

A comprehensive evaluation of potential causes is necessary to confirm the diagnosis of idiopathic granulomatous mastitis. Histologically, it is distinguished by the predominant presence of neutrophils and the absence of caseous necrosis. Treatment remains controversial, with recent literature supporting the efficacy of conservative management with steroid and immunosuppressive therapy, leaving surgical excision for complicated and refractory cases.

Conclusions

Idiopathic granulomatous mastitis is an uncommon breast condition where the exact causes and recommended treatment approaches are not well-defined. It is important to consider this condition in women who are in their reproductive years.

Highlights

• •Idiopathic granulomatous mastitis is a rare chronic benign inflammatory mastopathy.
• •The clinical and radiological aspects are variable.
• •It may be mistaken for breast cancer on mammography.
• •The pathological examination remains the main element of certain diagnosis.

1. Introduction

Idiopathic Granulomatous Mastitis (IGM) is a rare chronic inflammatory disease of the breast, characterized by a progressive painful breast mass. The disease is mainly reported in emerging countries, suggesting a possible ethnic predisposition. Although the etiology remains unknown, an autoimmune or hypersensitivity reaction is the most common hypothesis [1]. Diagnosis of IGM is generally based on histological examination [2]. We present here the case of a 36-year-old woman who was managed for idiopathic granulomatous mastitis. This case study and the accompanying literature review aim to contribute to a better understanding and improved management of IGM. This case report has been reported in line with the SCARE Criteria [3].

2. Case report

We received the case of a 36-year-old woman who had two pregnancies and two uncomplicated deliveries. The patient breastfed her two children for one year each. For three years, she used a combined estrogen-progestin contraceptive pill. She reported no breast trauma and no family history of tuberculosis, breast cancer, or autoimmune diseases.

The patient initially consulted a gynecologist because of right breast pain accompanied by swelling, starting three days before the consultation. She received a 5-day course of amoxicillin-based antibiotics, but symptoms showed no improvement. As a result, she decided to consult our facility for appropriate management.

On initial examination, t the patient was afebrile. Inspection of the breast revealed a swollen mass in the lower internal part of the right breast, accompanied by redness and retraction of the nipple. Upon examination, a palpable mass measuring 5 cm in diameter was detected. The central area of the mass had an irregular contour and measured 2 cm, causing significant pain. There was no nipple discharge and no palpable axillary adenopathy (Fig. 1).

Fig. 1.

Right breast pseudotumor, characterized by nipple retraction and “orange peel” appearance.

In response to these symptoms, an echo-mammogram was performed. Mammography revealed several localized areas of density, mainly in the lower internal quadrant of the right breast (Fig. 2). Ultrasound showed two areas of hypoechogenicity measuring 24 × 20 mm and 18.5 × 16 mm, and a few peri-lesional abscesses, the largest measuring 12 × 12 mm (BIRADS 4A). Granulomatous mastitis of the right breast was suspected (Fig. 3).

Fig. 2.

Localized areas of density in the lower internal quadrant of the right breast: mammographic findings.

Fig. 3.

Hypoechogenic areas and peri-lesional abscesses detected by ultrasound in the right breast.

An ultrasound-guided biopsy was carried out to obtain a tissue sample from the mass, and concurrently, the abscess was drained through a small incision performed under local anesthesia. Following the collection of pus for bacteriological analysis, the patient was commenced on intravenous antibiotic therapy with ceftriaxone at a dosage of 2 g per day.

The results of the biological tests demonstrated a CRP level of 10 mg/L and a white blood cell count of 11,000 per microliter. While local inflammatory signs had diminished, the patient persistently experienced pain, and there was evidence of purulent discharge at the site of drainage.

Histology, performed on three biopsy fragments ranging in length from 4 to 12 mm, showed no evidence of malignancy or pathogenicity. It revealed fibrous breast parenchyma with a polymorphic inflammatory infiltrate containing giant cells and aggregates of histiocytes, as well as at least one non-caseating granuloma and skin lesions. The usual stains (PAS, Grocott, Ziehl) were negative. These findings were consistent with granulomatous mastitis (Fig. 4).

Fig. 4.

High magnification microphotograph showing epithelial and gigantological-cellular granulomatous reaction without caseous necrosis (hematoxylin-eosin ×400).

An etiological work-up was carried out, including liver tests, thyroid work-up (TSH, anti-TPO, and anti-TG antibodies), autoimmune work-up (antinuclear and neutrophil cytoplasmic antibodies), syphilitic serology (VDRL, TPHA), angiotensin-converting enzyme measurement, prolactinoma, proteinuria test, serum calcium, serum creatinine, and chest X-ray. No abnormalities were detected.

The patient was diagnosed with IGM, and treatment was initiated with oral corticosteroids at a daily dose of 60 mg. After 15 days of treatment, significant improvement was observed, with the symptoms disappearing and the size of the mass shrinking to 1 cm. Subsequently, a gradual reduction in the corticosteroid dosage was implemented. One month later, the mass had completely resolved, and there were no signs of inflammation (Fig. 5).

Fig. 5.

Resolution of inflammatory signs and mass in the lower internal quadrant of right breast after one month of oral corticosteroid therapy.

After a period of clinical follow-up, initially every 3 months for one year and then every 6 months, the patient was symptom-free by the 18th month of monitoring.

3. Discussion

Idiopathic Granulomatous Mastitis (IGM) is a rare chronic inflammatory disease of the breast, the etiopathogenesis of IGM remains poorly understood [4]. Autoimmune mechanisms have been suggested, notably due to the association with autoimmune diseases such as Hashimoto's thyroiditis and polyangiitis with granulomatosis, as well as the presence of systemic manifestations and stigmata of autoimmunity. Some authors also highlight the possible role of extravasation of galactophoric substances following lesions of the ductal epithelium. Infectious agents such as lipophilic corynebacteria have also been studied, notably the presence of Corynebacterium kroppenstedtii in patients with IGM [5,6]. In addition, observations suggest a possible link between IGM and hyperprolactinemia due to lactation, treatment for prolactin adenoma, or neuroleptics [7].

IGM is mainly observed in women during the genital period. The links with pregnancy, breastfeeding, and oestroprogestogenic contraception remain unclear. The disease begins as unilateral inflammatory nodules, which may resemble cancer [8].

Typically, there is an absence of an inflammatory syndrome, and bacteriological and mycological samples yield negative results [8]. However, in cases of abscess, a mild inflammatory response and superinfection with Staphylococcus aureus may occur. Regarding immunological aspects, markers of autoimmunity may be detected, including positive rheumatoid factor and antinuclear antibodies [9].

The aim of imaging is to confirm mastitis, assess the extent of the lesion, and judge the effectiveness of conservative treatment. Imaging in mastitis presents a variety of non-specific features. Ultrasound can be used to assess the size of the lesion and guide the type of drainage required. Ultrasound findings include irregular hypoechoic masses with blurred contours, sometimes heterogeneous, with galactophore ectasia. Mammography often reveals asymmetrical focal density without micro-calcifications [10]. MRI may show lesions suspected of malignancy, with contrast after injection of gadolinium revealing peripheral enhancement. MRI is useful for assessing the extent and reduction of lesions [11].

Histological examination is essential for diagnosing IGM, typically revealing the presence of epithelioid granulomas without caseous necrosis. These granulomas are accompanied by a polymorphic inflammatory infiltrate comprising plasma cells, lymphocytes, and neutrophils. The inflammatory process is typically localized within the lobules. In some cases, more extensive involvement of the galactophoric and perigalactophoric regions, including micro-abscesses, has been observed [8]. Occasionally, a typical granuloma may be absent, and only a histiocytic infiltrate is present. Common staining methods such as PAS, Grocott, and Ziehl yield negative results [12].

IGM may present on its own or in association with a variety of inflammatory conditions. Initially, it may be challenging to differentiate between non-specific idiopathic granulomatous mastitis and granulomatous mastitis associated with autoimmune disorders. However, as the clinical progression of each patient unfolds, the distinction between the two conditions will become clearer. These autoimmune disorders include sarcoidosis, Wegener's disease, Horton's disease, periarteritis nodosa, non-Langerhansian histiocytoses such as Rosai-Dorfman and Erdheim-Chester, and hyper-IgG4 syndrome. When making a differential diagnosis, it is essential to distinguish IGM, from carcinomatous mastitis. Although mastitis may be associated with mammary tuberculosis, particularly in endemic areas, the predominance of neutrophils and the absence of caseous necrosis confirm the diagnosis of IGM [11]. It is crucial to distinguish between mastitis and infectious mastitis of bacterial, parasitic, or mycotic origin, as well as non-infectious granulomatous lesions such as lipophilic granuloma, cytosteatocrosis, sarcoidosis, plasma cell mastitis, and lymphocytic mastitis [13] (Table 1).

Table 1.

Recommended diagnostic work-up for inflammatory mastitis.

Diagnostic work-up for inflammatory mastitis
CBC, blood calcium, creatinine, liver function tests, CRP Serum protein electrophoresis
Antinuclear and neutrophil cytoplasmic antibodies
TPHA-VDRL
Prolactinemia
TSH, anti-TPO and anti-TG antibodies
Angiotensin converting enzyme
Proteinuria
Bacteriological and mycological tests
Surgical biopsy with anatomopathological
Accessory salivary gland biopsy, universal PCR (16S RNA)
Chest X-ray
Mammography, breast ultrasound, ±breast MRI
Thoracic-abdominal-pelvic CT scan

The treatment of IGM remains controversial. In the past, surgical excision of the mass alone was preferred, but this led to a high recurrence rate and postoperative complications such as fistulas, poor healing, and breast deformity. However, some studies have shown that excision alone or combined with steroid therapy is the most commonly used method. Recent studies suggest a conservative, non-surgical approach, reserving drainage of abscesses for only the small incisions deemed necessary [14].

For mild cases, careful monitoring is considered due to the possibility of spontaneous improvement. In the event of a positive bacteriological examination of pus, antibiotic therapy is recommended. In more severe cases, initial treatment often involves systemic corticosteroid therapy at a dosage of 0.5–1 mg/kg per day, which can be effective but may result in corticosteroid dependence [15].

Studies have shown that corticosteroids are effective in approximately 72 % of cases, with a 20 % relapse rate. Colchicine has been occasionally used as an immunomodulatory agent to potentially prevent relapses. In cases resistant to or dependent on corticosteroids, immunosuppressive drugs such as methotrexate or azathioprine may be considered. Surgery is an alternative for complicated or recurrent cases [16]. A literature review has indicated that the cure rate after partial mastectomy is higher compared to corticosteroid therapy (79 % vs. 42 %) [17]. An illustrative therapeutic algorithm is provided as a guide for managing IGM [11] (Fig. 6).

Fig. 6.

An illustrative therapeutic algorithm as a guide for managing IGM.

The course of IGM can be unpredictable, characterized by periods of remission and relapses. In severe cases, corticosteroid therapy is often necessary. Relapses are frequent, and the condition can affect both breasts [11].

Table 2 is a literature review highlighting various diagnostic and therapeutic strategies in case reported in the lasted decade.

Table 2.

literature review highlighting various diagnostic and therapeutic strategies in case reported in the lasted decade.

Study	Year	Age	Parity	Contraceptive	Breast cancer history	History of tuberculosis	Breast trauma	History breastfeeding	Symtom	Unilateral Bilateral	Time from symptoms to management	Initial physical examination	Homolateral axillary adenopathy	Erythema nodosum	Imaging findings	Localization	Biological investigations	Biopsy	Histology	Management	Total response	Time without recurrence (month)
Bacon at Al [16]	2021	23	G1P1	+: oral contraceptive pills 3 years	−	−	−	a	RB mass	2	2 months	RB:1.5 cm mass LB: Pain erythema and fluctuance	−	−	BI- RADS de catégorie 4A	RB at 8:00	RB: - LB: Corynebacterium kroppenst- edti	+	RB: granulation tissue, with at least 1 non–caseating granuloma LB: IGM	RB: oral steroids LB: Abscess was aspirated ATB Oral steroid	+	16
Oze [17]	2022	42	G5P5	+: Contraceptive device 5 years ago	−	−	−	a	RB swelling	1	3 months	Swelling RB local inflammatory signs, nipple retraction	+: 2,5 cm Mobile	−	BI- RADS de catégorie 4	Supero-external quadrant of the RB	+ infectious biology check-up: normal	+	IGM: Fibrous polymorphic inflammatory infiltrate and decentered epitheliogigantocellular granulomas of caseous necrosis	ATB and wound dressings	+	12
Mabuchi [18]	2022	30	G3P1(pregnante 31 weeks of gestation)	−	−	−	−	a	RB swelling and pain	1	1 week	Nodular mas Nipple discharge	+	+	Multiple low echoic lesions in the RB	Outer quadrants RB	+: White blood cells 18,150/μL CRp: 4.68 mg/dL	+	Non-caseating granuloma with epithelioid cells, neutrophils, and lymphocytes	ATB and draining abscess	+	a
Kornfeld [19]	2001	28	G3P1(pregnancy and breast feeding periode)	a	−	−	−	+	LB pain and swelling	1	a	lmass-like area. ery- thema	a	+	Illdefined hypoechoic mass-like area	LB 10:00 position 4 cm from the nipple	+: Tuberculosis autoimmune disease,serology: negative	+	GM	Oral steroids Injection triamcinolone mixed with lidocaine into the affected areas	−	a
Gupta et Al [20]	2020	35	G1P1	a	−	−	−	+	Lump in RB	2	2 months	RB: Erythem. Lump4 × 4 cm LB: Swelling and Erythem	−	−	RB: ill-defined heterogeneous echoes in the subareolar region LB: Abscess	Upper outer quadrant of the RB	+: Cultures: negative PCR test for TB: negative	−: breast mass excised under local anesthesia	Non-caseating granulomas and the absence of acid-fast bacilli	LB: Draining the abscess Oral steroids	+	8
Yoshino et Al [21]	2023	37	G4P2	Infertility treatment	−	−	−	a	Sensation of hardness in LB	1	1 week	LB: Erythema Induration	a	+	Pyogenic mastitis	a	white blood cell 14,360/μL CRP 14.75 mg/dL Culture: C. kroppenstedtii	+	Granulomatous mastitis	During pregnancy: ATB Draining the abscess After delivery: oral steroids	+	18
Almobarak et Al [22]	2021	34	G2P2	−	−	−	−	+	Painful lump LB	1	1 Month	LB: Mass, Inflammations sings Nipple retraction	+	−	Irregular hypoechoic soft-tissue mass, widely speculated	Outer upper quadrant LB	Grocott's Methenamine Silver and Ziehl–Neelse: negative. PCR test for TB: negative	−: FNAC	IGM	a	+	15
Mathew et Al [23]	2015	29	G2P2	+ contraceptive pills 2 years	−	−	−	a	Tender mass RB	1	1 week 1/2	Masse grapefruit bruising and erythema	−	−	RB: bulginghard mass	RB: mass centred at 3 o'clock	Antinuclear antibody HLA—B27: positive	+: ultrasound-guided biopsy	IGM	ATB Draining abscess Oral steroids	+	4
Curent case	2023	36	G2P2	+ contraceptive pills 3 years	−	−	−	+	Breast pain swelling	1	3 days	Mass measuring 5 cm erythema	−	−	BIRADS 4 A	RB lower internal quadrant	All investigations was normal	ultrasound-guided biopsy	IGM	ATB Draining abscess Oral steroids	+	18

RB: Right Breast.

LB: Left Breast.

IGM: Idiopathique Granulomatous mastitis.

ATB: antibiotherapy.

+: yes.

−: No.

1: Unilateral.

2: Bilateral.

FNAC: fine-needle aspiration cytology.

^aNo data.

4. Conclusion

IGM is an uncommon breast condition where the exact causes and recommended treatment approaches are not well-defined. It is important to consider this condition in women who are in their reproductive years.

The diagnosis of IGM requires a thorough investigation to rule out other possible causes.

Management is controversial, but a conservative approach is recommended.

CRediT authorship contribution statement

Abdelhamid Benlghazi, Moad Belouad, Hamza Messaoudi were responsible for the patient's diagnosis and clinical management. Abdelhamid Benlghazi wrote the manuscript. Hamza Messaoudi, Ait Bouhou Rachid contributed to the analysis, supervision, writing, reviewing, and editing of the manuscript for intellectual content. All authors have read and approved the final manuscript.

Declaration of competing interest

The authors declare no conflict of interest.

Data availability

No applicable.