Primary Necrotizing Fasciitis of the Breast: A Case Report and Review of the Literature

Case report

A 51-year-old Caucasian woman with type II diabetes mellitus presented with a seven-day history of pain, swelling and inflammation of the left breast. She was not lactating but had suffered several episodes of ‘mastitis’ in the same breast over the previous five months, treated by her general practitioner with oral flucloxacillin. On this occasion, flucloxacillin had been started four days earlier but anorexia, vomiting and marked clinical deterioration led to hospital referral. There was no history of trauma, surgery or diagnostic instrumentation to the breast.

The patient was a smoker, hypertensive and obese (body mass index 34) with osteoarthritis and bilateral total hip replacements and was taking glipizide, atenolol, bendroflumethiazide, lisinopril, tramadol, amitriptyline and nabumetone. On admission she had a fever (38 °C), tachycardia (110 beats/min) and hypotension (92/54 mmHg). White cell count was 10.6 × 10⁹ cells/L with a neutrophilia of 9.8 × 10⁹ cells/L. Serum albumin was 23 g/L, serum urea was 18.4 mmol/L and creatinine was 206 μmol/L revealing acute renal failure; renal function having been normal two months earlier.

The left breast was grossly inflamed throughout and extremely tender. The underside was leaking fluid and pus from multiple areas of black discolouration, necrosis and obvious liquefaction (Figure 1). The clinical appearance was of wet gangrene. Intravenous flucloxacillin, metronidazole and gentamicin were started immediately, and the patient was taken to theatre where gas bubbles and crepitus could be palpated in extensive areas of necrotic and liquefied tissue (Figure 2). Wide excision down to the healthy tissue of the chest wall was performed, resulting in an almost total mastectomy including the nipple/areolar complex. The wound was left open and packed with proflavin-soaked gauze. Postoperatively, four days of inotropic support were required in the intensive care unit (ICU).

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Figure 1

Necrotizing fasciitis of the left breast demonstrating severe cellulitis, inflammation, oedema and areas of necrosis

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Figure 2

Wide surgical excision of necrotic and liquefied tissue

A tissue sample sent to microbiology showed Gram-positive cocci, Gram-negative bacilli and mixed anaerobes sensitive to metronidazole. Clostridium perfingens was not identified. All blood cultures were negative. Histology confirmed necrosis and abscess formation with discolouration tracking up between the fatty septa of the breast. There was no evidence of malignancy. The diagnosis was type I necrotizing fasciitis (NF).

Three small areas of necrosis were excised in theatre 24 hours after the initial surgery and the wound was re-packed. Daily wound inspection and dressing changes were performed under sedation on ICU. Ward transfer was on day 5. Surgery on day 6 consisted of excision of the wound edges and secondary wound closure with mattress sutures. The patient was discharged home on day 9. Sutures were removed on day 16; however, the wound partially dehisced on day 20, necessitating re-admission to hospital and re-suturing under local anaesthetic. Regular outpatient follow-up took place until complete wound healing was confirmed, three months after initial closure.

Discussion

We report the third case in the literature of NF of the breast with no history of trauma, surgery or instrumentation. The only other documented cases involved patients of similar demographics.^1,2 Shah et al. ¹ reported a case in a 50-year-old, black, type II diabetic and Keune et al. ² in a 47-year-old Caucasian. NF of the breast has also been reported in the literature in postmastectomy wounds,^3–5 associated with ulceration of the breast^6,7 and following core needle biopsy. ⁸

NF is a rare and potentially life-threatening soft-tissue infection characterized by rapidly spreading inflammation, and subsequent necrosis of the fascial planes and surrounding tissue. ⁹ Microbial invasion of the subcutaneous tissues typically occurs through surgical site infection, blunt or penetrating trauma but may be idiopathic. Bacteria rapidly track through the fascial tissue planes and produce endo- and exotoxins. The result is tissue ischaemia, liquefactive necrosis and systemic toxicity. ¹⁰

Microbial classification of NF is classically divided into types I and II. Type I infections are polymicrobial in nature and are the more common, accounting for approximately 55–75% of all NF cases.^10–12 Tissue isolates typically demonstrate an average of four different organisms including a combination of Gram-positive cocci (Staphylococcus aureus and Streptococcus species), Gram-negative bacilli (Klebsiella species and Escherichia coli) and anaerobes. C. perfringens is now a rare cause of NF due to improvements in sanitation and hygiene. Type I infections typically occur in the perineum and trunk in immunocompromised patients, particularly diabetics and those with peripheral vascular disease. Other risk factors in type I NF include surgical incisions, blunt or penetrating trauma, abscesses, obesity, HIV, intravenous drug abuse (IVDA), alcohol abuse, indwelling catheters, insect bites and perforated colorectal cancer. ¹⁰ Diabetes has been shown to be an independent risk factor in the development of NF,^13,14 along with hypertension ¹³ and obesity. ¹³ Despite this, no precipitating cause is identified in between 20% and 50% of patients.^15,16 In contrast, type II infections are monomicrobial in nature and caused by either group A streptococcus (Streptococcus pyogenes) alone, or in association with S. aureus. ¹⁰ They are less common than type I infections and tend to occur in young, healthy, immunocompetent hosts, particularly at the extremities. Frequently, there is a history of trauma or surgery to the area. ¹⁰ In recent years, there has been an increasing incidence of community-acquired methicillin-resistant S. aureus NF reported, particularly in IVDAs, athletes and institutionalized groups. ¹⁷

Consistent with NF in other regions of the body, NF of the breast is most commonly type I;^1–3,6,7 however, type II NF has also been described.^4,5,8 Type II diabetes has been implicated in two^1,5 out of the eight other case reports of NF of the breast and at least two of these patients were also obese;^3,5 however, one patient had no identified risk factors. ²

Mortality from NF is high, with rates of around 25% currently reported. ¹⁸ In NF of the breast, there have been two reported deaths. ⁵ There are a number of variables that are associated with mortality in NF including age, ¹⁹ shock on admission, acute renal failure, diabetes mellitus, clostridia or group A streptococcal infection and the number of patient co-morbidities. ²⁰ However, the only variable that has been shown to be independently predictive of survival in multiple studies is timing to operative intervention. ¹⁰ Wong et al. ¹⁶ reported a nine-fold increase in mortality if the procedure was delayed by greater than 24 hours. Patients presenting with systemic toxicity and pain disproportionate to clinical signs should provoke a high index of clinical suspicion. Aggressive early management consisting of broad-spectrum intravenous antibiotics, extensive surgical debridement and ICU support is required. ²¹ Surgical debridement must remove the entire necrotic area, no matter how radical, and surgical incisions should be deep and extend beyond the areas of necrosis. The wound should be left open and re-inspected daily. Once the acute phase has resolved, delayed primary closure can be performed, although skin grafts or soft tissue flaps may be required for extensive defects. ²¹

Conclusion

We present a rare case of primary NF of the breast with no history of tissue insult. Certain risk factors have been identified, but NF may occur in previously healthy subjects and is most often polymicrobial in nature. Early diagnosis and aggressive treatment, including extensive surgical resection, is associated with improved survival but NF still carries a high mortality rate.