Introduction to Adenocarcinoma
In recent years, there have been an increasing number of cervical adenocarcinomas affecting young women in there twenties and thirties. Adenocarcinoma in situ is believed to be the precursor of invasive adenocarcinoma, and it is not surprising that the two often coexist. In addition, squamous neoplasia, intraepithelial or invasive, also occurs in 30-50% of cervical adenocarcinomas. Adenocarcinoma may be detected by cer¬vical sampling but less reliably so than squamous carcinomas. A definitive diagnosis may require cervical conization with subsequent tissue culture microscopy.
Invasive adenocarcinoma, when seen using tissue culture microscopy, may be pure or mixed with squamous cell carci¬noma-the adenosquamous carcinoma. Within the category of pure adenocarcinoma, the tumors are quite heterogeneous with a wide range of cell types, growth patterns, and differentiation. About 80% of cervical adenocarcinomas are made up predominantly of cells of the endocervical type with mucin production. The remaining tumors are populated by endometroid cells, clear cells,intestinal cells, or a mixture of more than one cell type. By histologic examination alone, with the help of a gynecological microscope, some of these tumors are indistinguishable from those arising elsewhere in the endometrium or ovary.
When using the latest tissue culture microscopy and medical microscopes, the growth patterns and nuclear abnormalities within each tumor type vary according to the degree of differentiation. In well-differentiated tumors, tall columnar cells line the well-formed branching glands andpapillary structures, whereas pleomorphic cells tend to form ir¬regular nests and solid sheets in poorly differentiated neoplasms. The latter may require mu¬cicarmine and periodic acid-Schiff (PAS) stains to confirm their glandular differentiation.
There are several special variants of adenocarcinoma. Minimal deviation adenocarcinoma (adenoma malignum) is an extremely well differentiated form of adenocarcinoma in which the branching glandular pattern strongly simulates that of the normal endocervical glands. In addition, the lining cells have abundant mucinous cytoplasm and uniform nuclei. Because of this, the tumor may not be recognized as malignant in small biopsy spec¬imens and its tissue culture microscopy, thereby causing considerable delay in diagnosis. Earlier studies reported a dismal outcome for women with this tumor, but more recent studies have found a favorable prog¬nosis if the disease is detected early. Although rare, similar tumors have also been re¬ported in association with endometrioid, clear, and mesonephric cell types.
Villoglandular papillary adenoca¬cinoma also deserves special attention. It primarily affects young women, some of whom are pregnant or users of oral contraceptives. Histologically, as seen in the gynecologic microscope and using the latest tissue culture microscopy, the tumors have smooth, well-defined borders, are well differentiated, and are either in situ or superfIcially invasive. The follow-up information is encouraging, however; none of these tumors has recurred after cervical conization or hysterectomy. Among women undergoing pelvic nodal dissection, no metastases have been detected in the tissue samples. This tumor appears to have limited risk for spread beyond the uterus.
In mature adenosquamous carcinomas, the glandular and squamous carcinomas are read¬ily identifIed on routine histologic sections using gynecologic microscope with the latest tissue culture microscopy and do not cause diagnostic problems. In poorly differentiated or immature adenosquamous carcinomas, however, glandular differentiation can be appreciated only with special stains, such as mucicarmine and PAS. In the study, 30% of squamous cell carcinomas demonstrated mucin secretion when stained with mucicarmine. These squamous cell carcinomas with mucin secretion have a higher incidence of pelvic lymph node metastases than squamous cell carcinomas without mucin secretion and are similar to the signet-ring variant of adenosquamous carci¬noma previously described by Glucksmann and Cherry.
Glucksmann and Cherry also recognized glassy cell carcinoma as a poorly differentiated form of adenosquamous carcinoma. Individual cells have abundant eosinophilic, granular, ground-glass cytoplasm, large round to oval nuclei, and prominentnucleoli. The stroma is infiltrated by numerous lymphocytes, plasma cells, and eosinophils. About one-half of these tumors contain glandular structures or stain positive for mucin. The poor diagnosis of this tumor is linked to understaging and resistance to radiotherapy.
Other variants of adenosquamous carcinoma include adenoid basal carcinoma and adenoid cystic carcinoma. Adenoid basal carcinoma simulates the basal cell carcinoma of the skin. Nests of basaloid cells extend from the surface epithelium deep into the underlying tissue. Cells at the periphery of tumor nests form a distinct parallel nuclear arrangement, the so-called “peripheral palisading.” An “adenoid” pattern occasionally develops, with “hollowed-out” nests of cells. Mitoses are rare, and the tumor often extends deep into the cervical stroma.
Adenoid cystic carcinoma of the cervix behaves much like such lesions elsewhere in the body. The tumor tends to invade into the adjacent tissues and metastasize late, often 8-10 years after the primary tumor has been removed. Like other adenoid cystic tumors, they may met-astasizedirectlyto the lung. The pattern simulates that of the adenoid basal tumor, but there is a cystic component and the glands of the cervix are involved. Mitoses may be seen but are not numerous.
