Inflammatory breast cancer (IBC) is one of the rarest and most aggressive forms of breast cancer, having relatively distinct clinicopathological features and the lowest survival rates. Its presentation was first described in 1814 by Bell as "a purple color on the skin over the tumor accompanied by shooting pains," which he identified as "a very unpropitious beginning."1 In 1889, Bryant noted the role of cancer cells obstructing the lymphatics in the development of inflammatory signs.2 The term "inflammatory carcinoma of the breast" was coined by Lee and Tannebaum in 1924. Currently, based on the American Joint Committee on Cancer (AJCC) Staging System, IBC is classified as T4d and described as a "clinicopathological entity that is characterized by diffuse erythema and edema (peau d'orange), often without an underlying mass. These clinical findings should involve the majority of the breast . . "3 It should be stressed that IBC is primarily a clinical diagnosis and thus, in the absence of clinical findings, involvement of the dermal lymphatics alone does not indicate the diagnosis of IBC. In this chapter, we review the epidemiology, clinical presentation, diagnostic modalities, and treatment, and discuss the current controversies of IBC.
The incidence of IBC is 1% to 6% in the United States. However, results from the 2005 Surveillance, Epidemiology, and End Results program revealed that the IBC incidence rate increased from 2.0/100,000 woman-years for 1988 to 1990 to 2.5/100,000 woman-years for 1997 to 1999. This is a marked contrast with the incidence rates for other types of invasive breast cancers, which decreased during the same time.4
Before 1990, it was believed that IBC was particularly prevalent in North Africa, specifically in Tunisia, because pre-1990 reports revealed a higher than 50% incidence of IBC in those areas.5 However, a review of 419 cases diagnosed as T4d between 1975 and 1996 at a single Tunisian institution revealed the incidence of IBC in Tunisia to be approximately 7%.5 This decrease in IBC incidence was attributed to the fact that prior studies had included not only T4d breast cancers, but also ulcerated breast cancers (T4b), which clearly exemplifies the complexities in the diagnosis of IBC.
Studies done using breast biopsy tissue from Tunisian patients with IBC revealed an increased incidence in the detection of viral sequences and antigens that resemble mouse mammary tumor virus.6 This relationship is currently under investigation in several institutions in the United States to confirm the etiopathogenetic role of mouse mammary tumor virus in IBC. Currently, various molecular factors associated with IBC have been identified, but the causative agent remains to be isolated.
IBC has a characteristic clinical presentation of skin changes and breast enlargement that occurs rapidly, typically within 3 months (Fig. 90-1).7 Although the AJCC definition calls for clinical findings to involve the majority of the breast, some researchers are calling for the disease to be diagnosed when there ...