A major change in this classification is the official recognition of adenocarcinoma in situ
as a second preinvasive lesion for lung adenocarcinoma in addition to atypical adenomatous hyperplasia.
In a study of 131 patients--the largest so far of women with adenocarcinoma in situ
(AIS) of the cervix--investigators at Brigham and Women's Hospital in Boston found that none of the 92 patients with negative margins on an initial cone biopsy developed a recurrence of AIS.
The 11 randomized cases included diagnoses of endometrial adenocarcinoma (SP); low-grade squamous intraepithelial lesion (TP and SP); high-grade squamous intraepithelial lesion (TP and SP); atypical squamous cells, cannot rule out high-grade lesion (SP); atrophic vaginitis (SP); Trichomonas vaginitis (TP); herpes (TP); adenocarcinoma in situ
(SP); and negative for intraepithelial lesion and malignancy with bacterial shift (SP).
One of the most important changes in terminology is the designation of neoplasms previously classified as bronchioloalveolar carcinoma as adenocarcinoma in situ
to emphasize that they tend not to spread to regional lymph nodes or to metastasize.
Tumors previously included in this term were separated into adenocarcinoma in situ
versus invasive adenocarcinomas.
For the 306 patients with HSIL or worse on index biopsy, subsequent LEEPs demonstrated no evidence of dysplasia or LSIL for 73 patients (24%); 223 LEEPs demonstrated HSIL (73%); and 10 LEEP biopsies demonstrated invasive adenocarcinoma (2), invasive squamous cell carcinoma (5), adenocarcinoma in situ
(1), or dysplasia not otherwise specified (2) (Table).
The seminal work of Masayuki Noguchi, MD, and many other Japanese pathologists, (13) informed discussion about the nature of those lesions that fulfilled criteria of BAC and reinforced the conclusion that this lesion represented adenocarcinoma in situ
17,30-39) This definition meant that bronchioloalveolar carcinoma was adenocarcinoma in situ
and, as such, could not be reliably diagnosed on a small biopsy or cytology specimen that did not allow examination of the entire tumor, to exclude any foci of invasion.
Helpful in this regard is the finding in primary SRCC of other adjacent cervical lesions, including high-grade dysplasia, adenocarcinoma in situ
, and squamous and adenosquamous carcinomas.
Identification of adjacent adenocarcinoma in situ
would be consistent with a neoplastic process in a questionable focus.
Even though most Papanicolaou (Pap) tests with AGC findings turn out to reflect a variety of underlying benign conditions, (8-10) a significant subset of AGC cases reflect underlying cervical intraepithelial neoplasia (CIN) grades 2/3 and/or endocervical adenocarcinoma in situ
(AIS) as well as occasional cases of invasive cervical and noncervical carcinoma.
Adenocarcinoma in situ
(AIS) is much less common than squamous intraepithelial lesion (SIL).