Cystic neutrophilic granulomatous mastitis – a review of 12 consecutive cases

Abstract

Cystic neutrophilic granulomatous mastitisa review of 12 consecutive cases Aims: Cystic neutrophilic granulomatous mastitis (CNGM) is an uncommon but increasingly recognised cause of mastitis, often associated with Corynebacterium ssp. infection. We studied the histopathological and clinical features of CNGM in a Canadian setting, and the work-up required to identify pathogenic microorganisms. Methods and results: A retrospective search for breast specimens with abscess, acute, chronic and/or granulomatous inflammation from 1998 to 2018 was performed. Haematoxylin and eosin slides were reviewed for typical histological features of CNGM. Histochemically stained slides for microorganisms were also reviewed. Repeat Gram stains were performed if initially negative. Electronic medical records were abstracted for microbiology results and relevant clinical data. Twelve cases were identified. All were female, aged 25-57 years, mainly Caucasian, with one Venezuelan and two of Chinese ethnicity. Most were parous (10 of 12); five of 12 had an endocrinopathy. Bacteria were identified in one or more specimens from eight of 12 patients; additional Gram stains revealed organisms in four of 12 cases. Of four bacterial cultures, one grew Corynebacterium kroppenstedtii. 16S polymerase chain reaction for three samples was negative. Two patients had multiple breast biopsies, showing early palisaded granulomas followed by classic features of CNGM. The patients had various management approaches, including surgery and antimicrobials. Conclusions: CNGM may present as palisaded granulomatous inflammation, without the expected 'cystic' pattern, suggesting that there is an evolution of histomorphology with this infection. Most patients with CNGM are parous, and there may be an association with endocrinopathies. Application of multiple Gram stains increases the yield of microorganism identification. Recognition of CNGM in breast biopsies and collaborative communications are essential to direct appropriate therapy.

Etiology of granulomatous lobular mastitis based on metagenomic next-generation sequencing

“…It lacks the characteristic cell envelope mycolic acid, of other Corynebacterium, so it can survive in lipid-rich conditions (Collins et al, 1998). However, the positive rate of Gram staining in paraffin tissue is relatively low (28%, 21/74) (Maung et al, 2020), even in positive cases, it is very challenging to determine the type of bacteria through microscopic observation due to the small number and small size of bacteria. Moreover, the culture condition of this bacterium is harsh and the growth is slow, which lead to low success rate of pathogen culture (Taylor et al, 2003).…”

Vacuoles in the Breast: A Histologic Clue for an Unusual Presentation of an Atypical Organism

“…Non-lactational abscesses are frequently identified, especially in smokers, and are typically caused by Staphylococcus spp or by anaerobic bacteria [17]. Prior instances of M. abscessus infections related to trauma and invasive cosmetic procedures, including breast prosthetic augmentation, breast reduction, liposuction, body-contour surgery, and blepharoplasty, have been described [18][19][20][21][22]. We are reporting a case of a subacute presentation of non-lactational breast abscesses in a woman without a history of trauma, cosmetic surgery, or breast neoplastic or non-neoplastic lesions.…”

Clinical features and recurrence of Corynebacterium kroppenstedtii infection in patients with mastitis

“…The present study is the first to review the largest cohort of Chinese patients with C. kroppenstedtii infection [ 16 , 18 , 21 – 23 ]. This study investigated the clinical features of C. kroppenstedtii infection in Chinese patients and explored the efficacy of local lavage (triamcinolone acetonide) and antibiotics (cefuroxime).…”