33 Special Types of Invasive Breast Carcinoma: Diagnostic Criteria ...

whether these lesions are in situ or invasive carcinomas, available outcome data
indicate that they seem to have an excellent prognosis with adequate local therapy
alone. Therefore, we believe it is most prudent to continue to manage patients with
these lesions as they are currently managed (ie, similar to patients with DCIS) and to
avoid categorization of such lesions as frankly invasive papillary carcinomas. Given
these observations these authors favored the term "encapsulated papillary carcinoma
(EPC)" over "intracystic papillary carcinoma" for circumscribed nodules of papillary
carcinoma surrounded by a fibrous capsule in which a peripheral layer of MEC is not
identifiable. In another study, Esposito and coworkers (22a) used collagen type IV
immunohistochemical procedure to assess “invasion” in 21 cases of pure EPC and 6
EPCs with adjacent invasive ductal carcinoma (IDC) and compared these results with
those for papilloma, DCIS, and IDC. Moderate to intense collagen type IV expression
was seen in all EPCs and was absent or decreased in all IDCs. All patients with pure
EPC had negative axillary nodes with the exception of 1 who had a micrometastasis,
and all were alive with no evidence of disease at follow-up (mean, 40.4 months). The
authors concluded that EPCs are in situ carcinomas with an excellent prognosis and
can be managed with local therapy with or without sentinel lymph node biopsy.
In the 41 cases reported by Carter et al. (1,9), extension of ductal carcinoma in situ
(DCIS) beyond the cyst into the small and medium sized ducts occurred in 46%, and
these cases were considered intracystic papillary carcinoma with DCIS. Patients with
pure intracystic papillary carcinoma did not have axillary nodal metastases or
recurrences, but about half of the cases with DCIS recurred, although the number of
cases was small. Fifteen separately identified patients who presented with intracystic
papillary lesions and truly invasive carcinoma (usually ductal type) had a ~73%
incidence of DCIS and two had positive axillary lymph nodes and eventually died
from breast carcinoma.
But, the association of aggressive or sometimes fatal behavior, in IPCs complicated by
adjacent DCIS or invasive carcinoma has not been observed by all. For example,
Solorzano et al. (23) identified three patient groups: IPC alone, IPC with associated
ductal carcinoma in situ (DCIS), and IPC with associated invasion with or without
DCIS. Forty patients were treated for IPC during the study period. Fourteen had pure
IPC, 13 had IPC with DCIS, and 13 had IPC with invasion. The incidence of
recurrence and the likelihood of dying of IPC did not differ between the three groups
regardless of the type of surgery (mastectomy or segmental mastectomy) performed
and whether radiation therapy was administered. The disease-specific survival rate
was 100%.
Likewise, in a second large follow-up study of 917 cases, Grabowski et al. (19) found
34