Granulomatous Mastitis and Factors Associated with Recurrence: An 11-Year Single-Centre Study of 113 Patients in Singapore.

BACKGROUND: Granulomatous mastitis (GM) is an inflammatory breast disease of unknown aetiology. It poses diagnostic and therapeutic challenges with myriad forms of clinical presentation, varying results to treatments and propensity to recur. This study aims to look at clinical and treatment factors that predispose to recurrence of GM. METHODS: We performed a retrospective review of 113 patients in our unit with histologically proven GM from 2006 to 2016. Demographic, clinical, treatment and outcomes data were collected and analysed. RESULTS: Eighty-nine patients were treated with antibiotics (78.8%), 79 (69.9%) with steroids and 23 (20.4%) patients underwent surgery. Twenty (17.7%) patients had recurrence. Patients who presented with inflammatory signs and symptoms had increased odds of having subsequent recurrence: skin changes (1.50), pain (2.00), fistula (4.39) and antibiotic treatment (6.65). Four patients (20%) with recurrence had positive bacterial cultures. All 4 grew Corynebacterium. Patients with Corynebacterium infection had a 2.64 times higher risk of recurrence. Surgery did not preclude recurrence. There was a 70% (7/10) penicillin resistance rate in our patients with positive cultures for Corynebacterium. CONCLUSION: Initial presentation with inflammatory signs and symptoms may confer increased risk of recurrence, warranting closer monitoring. Corynebacterium infection may play a part as a causative factor and risk factor for recurrence. Non-penicillin antibiotics should be considered as first-line antibiotics for patients presenting with inflammatory changes. Further prospective studies with larger patient populations might reveal information on the aetiology of GM and result in the development of a more standardized and effective treatment regimen.

Low-grade adenosquamous carcinoma of the breast: A diagnostic and clinical challenge.

Adenosquamous carcinoma of the breast (ASBC) is a rare variant of metaplastic breast cancer with both glandular as well as squamous differentiation. Their lack of distinct imaging characteristics, sometimes subtle histological characteristics and overlapping features with other benign lesions pose a diagnostic challenge. Unlike other forms of metaplastic breast cancer, low-grade adenosquamous carcinoma (LGAC) tends to follow an indolent course with favourable prognosis. We reviewed eight cases of LGAC in our institution from June 2005 to March 2014. In six cases, LGAC was only found after excisional biopsy. In our patients, LGAC frequently co-existed with other forms of breast pathology. Two patients had incidental findings of LGAC alongside their primary malignant tumour (adenoid cystic carcinoma and invasive ductal carcinoma in one, four foci between 0.5 and 4.0 mm within a radial sclerosing lesion adjacent to a malignant phyllodes tumour in the other). A further four patients had LGAC within a complex sclerosing lesion. One patient had a focus of LGAC within a fibroadenoma. One had a focus of LGAC within a benign phyllodes tumour. None of the patients had evidence of nodal involvement. A high degree of suspicion is recommended as such lesions tend to be incidental histological findings within benign tumours or within complex sclerosing lesions. Although the risk of nodal and distant metastasis is low, the potential for local recurrence necessitates aggressive local excision with margin clearance. The role of axillary dissection has yet to be defined and routine sentinel node biopsy and axillary clearance may not be necessary in view of rarity of nodal metastasis in literature. Benefit from adjuvant radiotherapy or chemotherapy is not clearly defined. All eight patients in our study have shown no evidence of recurrence after definitive surgery but longer periods of surveillance is required.