Rosen's Breast Pathology, 4e

921

Unusual Clinical Presentation of Carcinoma

FIG. 33.29.  Aberrant breast tissue. A: A mammary duct in the subcutaneous tissue around a carcinoma excised from the upper abdominal wall below the inframammary fold. B: Intraductal carcinoma in the same specimen. C: Infiltrating ductal carcinoma. carcinoma cases. 222 In institutional series, the frequency of IBC reportedly varies from 1% to 10%, depending upon diagnostic criteria and also upon the nature of the institution. Patientswith this condition are often referred to tertiary treatment centers where they constitute a relatively higher proportion of patients than would be encountered in general clinical practice. IBC has been reported to be more common in African Americans than in whites irrespective of whether clinical or histopathologic di­ agnostic criteria are used. 223–226 However, recent Surveillance, Epidemiology and End Results (SEER) data suggest that Afri­ can American women are generally susceptible tomore aggres­ sive forms of breast carcinoma, but not to IBC. 227 The disease was originally thought to be prevalent in Tunisia until a review revealed that ulcerated breast carcinomas had been included in the category of IBC, 228 exemplifying the importance of apply­ ing appropriate diagnostic criteria to characterize this disease. The age distribution of primary IBC is not significantly different from that of common infiltrating duct carcinoma, averaging about 55 years. It is only rarely encountered in children 229,230 and men. 231 Pregnancy and lactation do not predispose to the clinical presentation of IBC, although breast carcinomas that arise in this setting are prone to have lymphatic tumor emboli in the breast parenchyma. 232,233

chest wall. 217 Excisional biopsy confirmed the presence of in­ filtrating duct carcinoma that arose in ­ectopic breast tissue. Benign glandular inclusions in ALNs can mimic carci­ noma. This topic is considered in detail in Chapter 43.

INFLAMMATORY CARCINOMA In 1807, Charles Bell reported that “when a purple color is on the skin over the tumor it is a very unpropitious beginning.” 219 This is said to be the first clinical reference to inflammatory car­ cinoma . Lee and Tannenbaum 220 proposed the currently used term inflammatory carcinoma in 1924. In the latest American Joint Committee onCancer (AJCC) Staging System, inflamma­ tory breast carcinoma (IBC) is defined as “a clinical and patho­ logical entity characterized by erythema and edema involving a third or more of the skin of the breast,” and is classified as T4d. 221 IBC is not a specific histologic subtype of mammary carcinoma. However, some investigators have included histo­ pathologic findings among their diagnostic criteria. An assessment of the frequency of this uncommon condi­ tion depends largely on clinical reporting, but IBC is gener­ ally thought to account for not more than 2.5% of all breast