Granulomatous lobular mastitis co-existing with ductal carcinoma in situ: Report of three cases and review of the literature.

Granulomatous lobular mastitis (GLM) is a benign and infrequent chronic breast ailment. Although this lesion can be clinically and radiographically mistaken for early-onset breast cancer, it is a rare occurrence for the two to coexist. This report describes three such cases. In all three patients, the primary signs and symptoms were related to the formation of diffuse breast masses or abscesses. Breast ultrasound and MRI revealed glandular edema and dilated breast ducts. The biopsies of all lesions exhibited both granulomatous inflammation confined to the lobules of the breast, abundant interstitial inflammatory cell infiltrates, and apparently cancerous cells located in dilated ducts with intact basement membranes. The surgically excised specimens confirmed the diagnosis of GLM and ductal carcinoma in situ (DCIS) in all three patients who underwent breast mass resection. By clinical imaging and clinical manifestations, GLM may obscure a concurrent DCIS, as highlighted by the cases reported herein.

Idiopathic Granulomatous Mastitis Associated with Erythema Nodosum in a Pregnant Woman.

A 32-year-old woman at 17 weeks' gestation presented with fever and a 1-week history of an acute nodular eruption involving her legs, along with bilateral ankle and knee pain. She also had had a recurrent right breast abscess for 2 months for which she had been treated with oral antibiotics and surgical drainage, but with slight improvement. Cultures of the abscess showed no bacteria or fungi. She had no history of tuberculosis, sarcoidosis, trauma to the breast, or a family history of breast pathology. Cutaneous examination revealed multiple, tender, erythematous, subcutaneous nodules on her legs (Figure 1) and an ill-defined tender mass involving the inferior quadrant of the right breast without nipple discharge or retraction. There was a scar with drainage on her right breast (Figure 2). There were no regional lymphadenopathies. Left breast and left axilla examination was unremarkable. Significant laboratory findings included an erythrocyte sedimentation rate of 54 mm/hour (normal levels [NL] < 20 mm/hour), an elevated C reactive protein at 148 mg/L (NL < 5 mg/L), and a high level of white blood cells averaging 15,000 elements/mm3 (NL < 10,000/mm3).

The Distinct Pattern of Granulomatous Lobular Mastitis with Erythema Nodosum: More Severe Conditions and Extensive Lesions.

PURPOSE: Granulomatous lobular mastitis (GLM) is a benign inflammatory disease of the mammary gland with unknown etiology. Erythema nodosum (EN) is a rare, extramammary symptom of GLM. The purpose of this article was to investigate the clinical features of EN associated with GLM. METHODS: We recruited 102 GLM patients diagnosed between December 2018 and December 2021 at Renmin Hospital of Wuhan University. The clinical characteristics and laboratory indices of the EN group (n = 12) and the non-EN group (n = 90) were compared. RESULTS: The proportion of GLM patients with lesions involving ≥2 quadrants and high peripheral white blood cell count, absolute neutrophil count and neutrophil-to-lymphocyte ratio (NLR) was larger in the EN group than in the non-EN group (p = 0.002, 0.025, 0.014, 0.002, respectively). The duration of EN was longer in GLM patients with EN than in GLM patients without EN (p = 0.005). GLM patients with EN had more abscesses and sinus tracts than those without EN (p = 0.003, 0.038). Lesions involving ≥2 quadrants and the NLR were positively associated with the occurrence of EN (R = 0.304, 0.0302, p = 0.002, 0.002). Receiver operating characteristic curve analysis revealed that the area under the curve of the NLR was 0.770. When NLR > 5.73, the sensitivity and specificity of predicting EN were 66.67% and 87.78%, respectively. CONCLUSION: Our findings suggest that GLM concomitant with EN suggests the presence of a more severe condition and extensive lesions.

Clinical characteristics and therapeutic strategy of granulomatous mastitis accompanied by Corynebacterium kroppenstedtii: a retrospective cohort study.

BACKGROUND: Increasing evidence has suggested that Corynebacterium kroppenstedtii is associated with some cases of granulomatous mastitis, mostly based on pathology or microbiology. We aimed to identify the clinical characteristics and treatment regimens for granulomatous mastitis with Corynebacterium kroppenstedtii infection. Understanding these clinical features is essential for patient care. METHODS: We retrospectively collected data on 201 patients who were pathologically diagnosed with granulomatous mastitis and had microbiological results of either Corynebacterium kroppenstedtii or no bacterial growth and recorded and analysed their demographics, clinical characteristics, and clinical outcomes. RESULTS: There were 107 patients in the CK group and 94 patients in the negative group. Sinus formation (x2 = 13.028, p = 0.000), time to complete remission at the first treatment period (Z = -3.027, p = 0.002), diameter of breast mass at first-time medical consultancy (Z = -2.539, p = 0.011) and recurrence (x2 = 4.953, p = 0.026) were statistically significant. Age (Z = -1.046, p = 0.295), laterality (x2 = 4.217, p = 0.121), time to presentation since the last delivery (x2 = 0.028, p = 0.868), BMI (Z = -0.947, p = 0.344), lactation time (Z = -1.378, p = 0.168), parity (x2 = 1.799, p = 0.180), gravida (Z = -0.144, p = 0.885), history of lactational mastitis or abscess (x2 = 0.115, p = 0.734), local trauma (x2 = 0.982, p = 0.322), hyperprolactinemia (x2 = 0.706, p = 0.401), erythema nodosum (x2 = 0.292, p = 0.589), and nipple discharge (x2 = 0.281, p = 0.596) did not demonstrate statistical significance. Regarding recurrence related to therapeutic strategy, except for surgery combined with immunosuppressants (x2 = 9.110, p = 0.003), which was statistically significant, none of the other treatment regimens reached statistical significance. The recurrence rate of patients in the CK group using rifampicin in their treatment course was 22.0% (x2 = 4.892, p = 0.027). CONCLUSIONS: Granulomatous mastitis accompanied by Corynebacterium kroppenstedtii more easily forms sinuses and has a higher recurrence rate. Both of the clinical characteristics may indicate that Corynebacterium kroppenstedtii plays an important role in the development and progression of granulomatous mastitis. Lipophilic antibiotics may be essential for granulomatous mastitis with Corynebacterium kroppenstedtii infection.

Profiling Microbial Communities in Idiopathic Granulomatous Mastitis.

Idiopathic granulomatous mastitis (IGM) is a rare and benign inflammatory breast disease with ambiguous aetiology. Contrastingly, lactational mastitis (LM) is commonly diagnosed in breastfeeding women. To investigate IGM aetiology, we profiled the microbial flora of pus and skin in patients with IGM and LM. A total of 26 patients with IGM and 6 patients with LM were included in the study. The 16S rRNA sequencing libraries were constructed from 16S rRNA gene amplified from total DNA extracted from pus and skin swabs in patients with IGM and LM controls. Constructed libraries were multiplexed and paired-end sequenced on HiSeq4000. Metagenomic analysis was conducted using modified microbiome abundance analysis suite customised R-resource for paired pus and skin samples. Microbiome multivariable association analyses were performed using linear models. A total of 21 IGM and 3 LM paired pus and skin samples underwent metagenomic analysis. Bray−Curtis ecological dissimilarity distance showed dissimilarity across four sample types (IGM pus, IGM skin, LM pus, and LM skin; PERMANOVA, p < 0.001). No characteristic dominant genus was observed across the IGM samples. The IGM pus samples were more diverse than corresponding IGM skin samples (Shannon and Simpson index; Wilcoxon paired signed-rank tests, p = 0.022 and p = 0.07). Corynebacterium kroppenstedtii, reportedly associated with IGM in the literature, was higher in IGM pus samples than paired skin samples (Wilcoxon, p = 0.022). Three other species and nineteen genera were statistically significant in paired IGM pus−skin comparison after antibiotic treatment adjustment and multiple comparisons correction. Microbial profiles are unique between patients with IGM and LM. Inter-patient variability and polymicrobial IGM pus samples cannot implicate specific genus or species as an infectious cause for IGM.

Autoimmune rheumatic diseases associated with granulomatous mastitis.

Granulomatous mastitis (GM) is a benign, inflammatory condition of the breast that mainly affects women of reproductive age. Although its pathogenesis remains unknown, previous studies revealed an association between autoimmune rheumatic diseases (ARDs) and GM in a subset of patients implicating immune-mediated mechanisms. The aim of this narrative review was to identify and describe the ARDs associated with GM to shed further light on disease pathogenesis. We conducted a comprehensive literature search of patients presenting with GM and coexisting ARDs using electronic databases. An association between GM and various ARDs has been reported, including sarcoidosis, systematic lupus erythematosus, granulomatosis with polyangiitis, psoriasis/psoriatic arthritis, familial Mediterranean fever, ankylosing spondylitis, Sjogren's syndrome, rheumatoid arthritis, and erythema nodosum, with the most common being granulomatous mastitis-erythema nodosum-arthritis syndrome (GMENA), granulomatosis with polyangiitis (Wegener's) and sarcoidosis. In addition, clinical characteristics, diagnostic and therapeutic approaches were recorded. Further research is warranted to better understand the association between GM and ARDs and raise awareness amongst rheumatologists.

Granulomatous mastitis, erythema nodosum, and polyarthritis: a case report.

BACKGROUND: Granulomatous mastitis is a rare inflammatory disease of the breast, typically seen in woman of child-bearing age. No definitive etiology has been described. In rare instances, this condition has been reported to be associated with extramammary manifestations such as erythema nodosum and arthritis. We describe this rare condition in an adolescent female. CASE PRESENTATION: A 16-year-old, Hispanic female presented with right-sided painful breast swelling, polyarthritis, and erythema nodosum on bilateral shins and lower thighs. Physical examination was negative for lymphadenopathy and pulmonary, gastrointestinal, and cardiovascular findings. Ophthalmologic examination for uveitis and serologic tests for autoimmune diseases were negative. Diagnosis of idiopathic granulomatous mastitis was made by exclusion of other etiologies and conditions. Confirmation was made by histopathologic examination demonstrating noncaseating granuloma within breast lobules with neutrophils and microabscess formation. After wide local excision and a short course of trimethoprim-sulfamethoxazole, our patient was placed on naproxen and prednisone, the latter being tapered off over 3 months, with steady and complete resolution of all symptoms. CONCLUSION: This is the first reported case of idiopathic granulomatous mastitis in a pediatric patient who also had extramammary manifestations, including erythema nodosum and polyarthritis. In this case-based review, we summarize the phenotype, risk factors, prognosis, and treatment options of this rare condition, chiefly to make the readers cognizant of such a diagnostic possibility in similar clinical presentation in the future.

Mastitis granulomatosa asociada a eritema nudoso: estudio de 42 casos / Granulomatous mastitis associated with erythema nodosum: A case series of 42 patients

Introducción:La mastitis granulomatosa (MG) se define por la presencia de inflamación granulomatosa en el tejido mamario. El eritema nudoso (EN) es una paniculitis inflamatoria reactiva caracterizada por nódulos subcutáneos dolorosos en las extremidades inferiores. La asociación entre MG y EN ha sido descrita, pero está poco estudiada. Nuestro objetivo fue analizar las características clínicas de las pacientes diagnosticadas de MG en nuestro centro y su asociación con EN.Métodos:Se revisaron retrospectivamente los casos diagnosticados histológicamente de MG entre 1995 y 2020.Resultados:Cuarenta y dos mujeres fueron diagnosticadas de MG. La edad media al diagnóstico fue de 41,619años y el 59,5% tenían ascendencia sudamericana. El EN se asoció con MG en el 11,9% de las pacientes. Las pacientes con EN fueron diagnosticadas precozmente respecto a aquellas con MG aislada (0,4meses frente a 6,81; p<0,05). La ulceración en la MG fue más prevalente en pacientes con EN asociado (60% vs 14,7%; p<0,05).Conclusión:El EN en pacientes con GM puede facilitar el diagnóstico precoz de esta rara condición que imita el cáncer de mama.(AU)

Background:Granulomatous mastitis (GM) is defined by the formation of granulomatous inflammation in breast tissue. Erythema nodosum (EN) is a reactive inflammatory panniculitis characterized by erythematous subcutaneous nodules in the lower limbs. The association of GM with EN has been rarely reported. Our aim was to retrospectively review our series of patients with GM to better characterize their features and their association with EN.Methods:Cases histologically diagnosed as granulomatous inflammation in breast tissue between 1995 and 2020 were retrospectively reviewed.Results:Forty-two women were diagnosed with GM. The average age at diagnosis was 41.619years, and 59.5% were of South-American ethnicity. EN was associated with GM in 11.9% of the patients. Patients with EN were diagnosed earlier than isolated GM (0.4months vs 6.81months; P<.05). Ulceration in the GM was more prevalent in patients with associated EN (60% vs 14.7%; P<.05).Conclusion:EN in patients with GM may reduce the evolution time and may help to diagnose this rare condition that mimics breast carcinoma. (AU)

Gynecomastia with rare granulomatous lobular mastitis: a case report and literature review.

This study was performed to describe a rare case of granulomatous lobular mastitis (GLM) that was successfully treated with bromocriptine in a male patient with gynecomastia and hyperprolactinemia. A 20-year-old man presented with a 1-year history of breast enlargement and galactorrhea. Physical examination revealed bilateral breast enlargement, porous discharge, and a 3-cm left breast lump in the 10-o'clock quadrant. Magnetic resonance imaging of the brain showed a 1.2-mm pituitary tumor. Laboratory analysis revealed hyperprolactinemia with low serum testosterone and elevated prolactin and estradiol levels. The lump in the left breast was examined by ultrasonography and mammography, and a core needle biopsy revealed chronic inflammation. The patient's galactorrhea and breast lump disappeared after 3 months of treatment with bromocriptine at 2.5 mg once a day. His serum prolactin level also normalized. Following a review of this case, the patient was diagnosed with gynecomastia with hyperprolactinemia complicated by rare GLM. To the best of our knowledge, this is the first reported case of concurrent gynecomastia and GLM.

[Idiopathic granulomatous mastitis associated with erythema nodosum: a case report]. / Mastite granulomateuse idiopathique associant un érythème noueux: à propos d'un cas.

Idiopathic granulomatous mastitis (IMD) is a chronic benign inflammatory disease of the breast which can mimic breast cancer. It is more common in young women of childbearing age and poses a challenge in diagnosis of inflammatory breast tumor. We report the case of a 26-year-old female patient who presented with inflammatory breast. Clinical examination showed apyretic patient with edematized and painless irregular smooth mass in the left breast measuring 4 cm surmounted by crusts and multiples fistulizing scars discharging pus by applying pressure, with mobile ipsilateral axillary adenopathy. The remainder of the physical examination showed inflammatory erythematous patches on both legs. A mammogram plus breast ultrasound was performed followed by biopsy that objectified fibrous mastopathy. Lumpectomy was performed due to the persistence of symptoms. Anatomopathological examination objectified granulomatous mastitis. Etiological research didn't identify a clear cause. Corticotherapy associated with antibiotic therapy was started with complete regression of symptoms after two months.

[Granulomatous mastitis associated with erythema nodosum: A case series of 42 patients]. / Mastitis granulomatosa asociada a eritema nudoso: estudio de 42 casos.

BACKGROUND: Granulomatous mastitis (GM) is defined by the formation of granulomatous inflammation in breast tissue. Erythema nodosum (EN) is a reactive inflammatory panniculitis characterized by erythematous subcutaneous nodules in the lower limbs. The association of GM with EN has been rarely reported. Our aim was to retrospectively review our series of patients with GM to better characterize their features and their association with EN. METHODS: Cases histologically diagnosed as granulomatous inflammation in breast tissue between 1995 and 2020 were retrospectively reviewed. RESULTS: Forty-two women were diagnosed with GM. The average age at diagnosis was 41.619years, and 59.5% were of South-American ethnicity. EN was associated with GM in 11.9% of the patients. Patients with EN were diagnosed earlier than isolated GM (0.4months vs 6.81months; P<.05). Ulceration in the GM was more prevalent in patients with associated EN (60% vs 14.7%; P<.05). CONCLUSION: EN in patients with GM may reduce the evolution time and may help to diagnose this rare condition that mimics breast carcinoma.

Idiopathic granulomatous mastitis associated with erythema nodosum may indicate a worse prognosis.

INTRODUCTION: Idiopathic granulomatous mastitis (IGM) is a chronic inflammatory breast disease of unknown etiology, and erythema nodosum (EN) is a rare extramammary manifestation of this entity characterized by reddish, tender nodules of the lower legs. We aimed to investigate whether the association of IGM with EN has a role as a prognostic indicator. There are few case reports, and only 1 original article including 12 IGM patients with EN has been reported. METHODS: We present 43 women with IGM coexisting with EN and 43 with a diagnosis of IGM only, who were randomly selected from 610 patients for a control group. To the best of our knowledge, this paper comprises the first comparative study of the coexistence of IGM and EN to be reported in the literature. RESULTS: Our findings show that the association of IGM with EN indicates a more aggressive disease course. White blood cells, erythrocyte sedimentation rate, and C-reactive protein were significantly higher in the EN-positive group (P < .05). Arthralgia, breast feeding, fistula distribution and recurrence distributions were significantly higher in the EN-positive group (P < .05). CONCLUSION: Since fistula distribution and recurrence rates were higher in EN-positive group, association of IGM with EN may be an indictor of a worse prognosis. The present study highlights the importance of dermatological care. All physicians should not neglect questioning breast complaints in patients with EN since EN may be caused by IGM.

Clinical characteristics and predictive factors of erythema nodosum in granulomatous lobular mastitis.

BACKGROUND/OBJECTIVES: In recent years, there is a growing incidence of granulomatous lobular mastitis (GLM), but studies about the coexistence of erythema nodosum (EN) and GLM are rare. In this study, we assess the clinical characteristics and predictive factors of EN in GLM. METHODS: A total of 303 patients diagnosed with GLM were enrolled from January 2012 to October 2018 at the second affiliated Hospital of Guangzhou University of Traditional Chinese Medicine, including 78 patients with EN. Follow-up data included: lesion site, lesion size, therapy approaches, course of GLM, course of EN, the recurrence of disease, possible causes. All patients had pathologic confirmation of GLM based on core needle biopsy (CNB) or surgical excision. RESULT: Fever in the EN group was significantly more common compared to the non-EN group (44.87% vs 12.89%, P < 0.001). The proportion of lesion range >2 quadrants in the EN group was significantly higher than that in the non-EN group (42.31% vs 16.00%, P < 0.001). The course of the disease was longer in the EN group compared to the non-EN group (10.32 moths vs 8.74 moths, P < 0.001). Patients with EN had a trend towards a higher risk of recurrence (5.13% vs 1.33%, P = 0.055). CONCLUSION: EN is more likely to be found in GLM patients with breast lesion range >2 quadrants. The presence of EN in GLM indicates that the condition becomes more severe and the course of GLM also becomes longer.

Granulomatous mastitis, erythema nodosum and arthritis syndrome: case-based review.

Granulomatous mastitis (GM) is a rare form of inflammatory breast condition associated with unilateral or bilateral breast pain, swelling and mass formation. Although the disease pathogenesis remains unknown, several reports have associated GM with manifestations such as erythema nodosum and occasionally with arthritis, suggesting that GM might have an autoimmune disease component. We aim to describe two cases of coexistence of GM, erythema nodosum, and arthritis. We also conducted a literature review to comprehensively assess and describe the characteristics of patients with GM, erythema nodosum, and arthritis, and identify effective treatment options. A literature review was conducted using PubMed and EMBASE, and 14 case reports/series were retrieved, with a total number of 29 patients. All patients are women and unilateral breast involvement was evident in the majority of patients. Nine patients (31%) presented with arthritis, 6 patients (20.7%) had a fever, and 6 patients (20.7%) developed the symptoms during pregnancy. All patients had normal chest radiograph and tissue cultures were negative. In most of the cases (n = 25, 86.2%), symptom improvement was observed with glucocorticoids and four patients (13.8%) underwent surgical treatment for the GM. Given the clinical characteristics of patients with GM, with erythema nodosum, with or without arthritis, and the positive response to glucocorticoids, we propose that the described phenotype represents an underrecognized systemic autoimmune disease that could be designated by the acronym "GMENA" (granulomatous mastitis, erythema nodosum, arthritis) syndrome. Further studies are needed to elucidate the pathogenesis of the syndrome.

Patients with idiopathic granulomatous mastitis accompanied by erythema nodosum.

BACKGROUND: Idiopathic granulomatous mastitis (IGM) is a rare, chronic inflammatory disease of the breast. The aetiology is unknown. Erythema nodosum (EN) is a rare skin disease associated with IGM. EN is a disease in which the aetiologic factors include infection, malignancy, autoimmune diseases, and pregnancy. OBJECTIVE: The objective of this study was to evaluate the incidence and coexistence of EN with IGM and the approach to treatment. METHODS: Patients who were admitted to the General Surgery and Dermatology Department of our hospital and diagnosed with EN and IGM were evaluated. Demographic data, symptoms, examination findings, number of birth, smoking, diagnosis and treatment methods, recurrence, and follow-up periods of the patients were evaluated. RESULTS: EN was seen in six of the patients admitted to the clinic for IGM. Four patients with EN had pregnancy and all had arthritis. Two patients were not pregnant. Oral methylprednisolone treatment was started in patients whose IGM diagnosis was verified pathologically. CONCLUSION: IGM may be associated with extramammary symptoms such as EN, arthralgia, and episcleritis. These extramammary findings suggest that IGM may be an autoimmune disease. For this reason, breast examination and history of IGM of the breast should be questioned in female patients admitted to different clinics with EN. This way, delays in the diagnosis and treatment of IGM can be prevented.

A case report of TB versus idiopathic granulomatous mastitis with erythema nodosum, reactive arthritis, cough, and headache.

Tuberculous mastitis (TBM) is relatively rare disease with an incidence ranging between 0.1 and 4%. Most of the cases are culture negative and often mistaken with chronic benign idiopathic granulomatous mastitis (IGM). It is very crucial to distinguish culture negative TBM from other causes of mastitis as the treatment differs tremendously. We describe here in a young woman originally from India and residing in Qatar; a non endemic area of tuberculosis; for more then fifteen years. She presented with 2 months history of right breast mass, followed by low grade fever, dry cough, headache, erythema nodosum, arthritis, and arthralgia. In view of the origin of the patient, positive family history for tuberculosis and positive quantiferon, the patient was started empirically on anti-tuberculous treatment (ATT). One week later she developed paradoxical reaction to ATT. This case illustrates unusual and rare manifestations of primary TBM and highlights the importance of differentiating and treating culture negative TBM from IGM.

[Idiopathic granulomatous mastitis associated with erythema nodosum]. / Mastite granulomateuse idiopathique associée à un érythème noueux.

BACKGROUND: Idiopathic granulomatous mastitis (IGM) is a rare, chronic, granulomatous, inflammatory disorder with potentially misleading clinical and radiological features. IGM is diagnosed after exclusion of infectious or tumoral diseases. Herein we report a case of erythema nodosum associated with IGM, which serves as a reminder that erythema nodosum may constitute an extra-mammary sign of IGM. PATIENTS AND METHODS: A 36-year-old nulliparous woman presented with fever and skin rash at our dermatology clinic at the North Franche-Comté hospital in July 2017. Symptoms had occurred 2 days previously. The patient had a fever of 38.8°C and typical erythema nodosum on the limbs. Physical examination showed an irregular, inflammatory, abscessed mass measuring 20cm with multiple shrinkage zones that had been developing for 4 weeks and for which breast examinations were being performed. Laboratory tests showed an inflammatory state (CRP 155mg/mL, WBC 14.6×109/L), other tests (serum electrolytes and calcium, hepatic and renal tests, Streptotest, T-spot, HIV, HBV, HCV serology, anti-streptolysin, anti-streptodornase, local microbiology samples, antinuclear antibodies, soluble antigens antibodies, hemocultures, angiotensin-converting-enzyme and chest x-rays) were normal. Microbiology investigations were negative. Mammography revealed invasive mastitis. Breast sample biopsies showed giant cell granulomas without caseous necrosis or tumor cells, and histochemical staining (PAS, Ziehl, Grocott, Gram) was negative. The final diagnosis was of IGM associated with erythema nodosum. Symptoms rapidly improved with oral steroids. DISCUSSION: As reported herein, erythema nodosum may be associated with IGM and support the diagnosis thereof. This association is rare, with fewer than 30 case reports described in the literature. IGM is an uncommon benign disorder of the breast that can mimic two frequent breast disorders: breast carcinoma and breast abscess. It usually occurs in young sexually active women. It appears as a tumor with an inflammatory solid painful mass, with nipple and skin retraction, occasionally with abscesses and accompanied by homolateral axillary lymphadenopathies. Radiologic findings are usually not specific for or suggestive of cancer. The histopathological picture of IGM is characterized by the presence of multinucleated giant cells and epithelioid histiocytes forming non-caseating granulomas around lobules. Minor ductal and periductal inflammation is usually present. IGM is rarely associated with autoimmune system manifestations, especially erythema nodosum, arthritis, episcleritis or hidradenitis suppurativa. Although the physiopathology of IGM remains unclear, this case serves as additional evidence that the etiology of IGM is of autoimmune origin. While there is no recommendation for the treatment of IGM, oral steroids remain the cornerstone of therapy. CONCLUSION: We report a case of IGM associated with erythema nodosum. Dermatologists must be aware of this association.