Inflammatory Breast Cancer
interfere with HER2 expression’s well-known predictive significance to trastuzumab treatment, and all IBC patients with HER2 overexpression should be treated with trastuzumab.
Impact of Dermal Lymphatic Invasion on the Prognosis of Inflammatory Breast Carcinoma Historically, clinical presentation that resembles non-malignant acute mastitis was the main reason for delay in diagnosis and treatment in many patients. However, this typical clinical presentation of breast skin inflammation is not due to true physiological inflammatory response but is rather a consequence of pathological plugging of the dermal lymphatic of the breast with tumour emboli.
This pathological phenomenon was observed long ago, when Thomas Bryant in 1887 observed pathological tumour invasion of the dermal lymphatic vessels, recognising that lymphatic obstruction produced the clinical appearance of inflammation.23
Later, IBC was determined as a clinical entity in which confirmation of dermal lymphatic invasion (DLI) is equivalent to ‘pathological proof’ of this rare malignancy, because it is caused by filling of the dilated dermal lymphatics by tumour emboli, subsequently leading to lymphatic obstruction and producing the typical inflammatory appearance.24
This was so convincing as a dominant pathology event for many researchers that they preferred the pathological over the clinical definition for IBC, proposing “dermal lymphatic carcinomatosis of the breast” as the alternative phrase instead of inflammatory breast carcinoma.25,26
However, it was soon recognised that even with an adequate number of tissue-block samples and multiple sections (≥10), dermal lymphatic tumour emboli are evident in up to 80 % of patients with true primary IBC and the diagnosis of inflammatory carcinoma is still made primarily on clinical grounds. However, the absence of DLI does not exclude the diagnosis of IBC.5
Inflammatory Breast Carcinoma Subtypes Because of those peculiar characteristics, it has been suggested that there may be three subtypes of IBC according to combined clinical and/or pathological features.27–31
In another study, with an impressively high number of breast cancer specimens examined (51,030), a total of 3,172 patients had IBC (6 %).1
The first IBC subtype is characterised by clinical inflammation but without pathological plugging of the dermal lymphatic. The second subtype has pathological plugging of the dermal lymphatic but without clinical signs of inflammation. And finally, the third subtype is fully developed IBC with both clinical inflammation and pathological involvement of the dermal lymphatic. It could be speculated that prognosis of patients with the above-mentioned three types of IBC differs, and that a combination of DLI with a full inflammatory component might be the worst. Among all mentioned IBC subtypes, the rarest is one with DLI but without an inflammatory component, and from a clinical aspect the true prognostic significance of this rare IBC subtype is still a matter of debate. According to the results of one study, 836 mastectomy specimens were re-examined and only 15 patients (1.8 %) were identified with DLI but without inflammatory disease (ID).31
Among these patients only 81 had DLI but without the inflammatory component of IBC, which represents only 0.16 % of
EUROPEAN ONCOLOGY & HAEMATOLOGY Figure 3: Inflammatory Breast Carcinoma
Figure 1: Locally Advanced Breast Carcinoma with Secondary Inflammation
Figure 2: Inflammatory Breast Carcinoma
patients with IBC. Therefore, this subtype clearly represents the rarest form of IBC.
However, skin involvement in IBC is technically always interpreted as a metastatic site at the time of primary diagnosis. Therefore, it could be expected that proven skin involvement actually represents the most important factor for generally poorer prognosis of patients with IBC. In fact, it has been proposed that DLI is responsible for the high metastatic potential of IBC.32
Indeed, the impact of DLI on clinical course and definitive outcome has been explored, but in a surprisingly small number of publications. Because contemporary anthracycline- and taxane-based chemotherapy treatment is now widely used in everyday clinical practice, the prognosis of patients with IBC has been generally improved. There are reports of long-term survival, with five-year
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