A routine Pap test, or cervical screening, is a standard health procedure designed to detect abnormal cells in the cervix before they can develop into cancer. One result is the finding of Atypical Glandular Cells (AGC). This result indicates that the cells lining the inner part of the cervix or the uterus have an abnormal appearance. This signals the need for further investigation to determine the nature and source of the cellular changes.
What Atypical Glandular Cells (AGC) Mean
The cervix is covered by two main types of cells: squamous cells (outer part) and glandular cells (inner cervical canal). An AGC finding specifically relates to an abnormality in the glandular cells. Unlike the more common Atypical Squamous Cells (ASCUS), an AGC diagnosis is less frequent, appearing in less than one percent of all cervical cytology specimens.
The term “atypical” means the glandular cells show changes that are more concerning than simple inflammation or a benign reaction, but they do not yet display the definitive characteristics of a pre-cancerous or cancerous lesion. A pathologist uses this category when the cell abnormalities are pronounced enough to warrant concern but not clear enough to be labeled as Adenocarcinoma in situ (AIS) or invasive cancer. Because these cells line the endocervical canal, which is higher up and less visible, the finding is treated seriously.
Pathology reports further categorize AGC findings, which helps guide the subsequent evaluation. Subcategories include:
- Atypical Endocervical Cells (AGC-EC)
- Atypical Endometrial Cells (AGC-EM)
- Atypical Glandular Cells Not Otherwise Specified (AGC-NOS)
The AGC-EC designation suggests the abnormality originates in the cervical canal lining, while AGC-EM points toward cells from the uterine lining (endometrium). The “NOS” category is used when the cellular origin cannot be definitively determined, requiring a comprehensive workup to pinpoint the source.
Statistical Risk of Cancer Following an AGC Result
The finding of Atypical Glandular Cells is clinically significant because it carries a higher risk of underlying serious pathology compared to other atypical results like ASCUS. Studies show that 10 to 40 percent of women diagnosed with AGC will have a significant lesion upon follow-up diagnostic procedures. These lesions include High-Grade Squamous Intraepithelial Lesion (HSIL), Adenocarcinoma in situ (AIS), or an invasive cancer.
The risk of finding an invasive cancer is lower than finding a precancerous lesion, but it is still elevated compared to a normal Pap result. Approximately 1.4 percent of women with an AGC result are found to have prevalent cervical cancer within six months. The vast majority of these cancers are adenocarcinomas, originating from glandular cells, accounting for 73 to 74 percent of invasive cancers found after an AGC diagnosis.
The specific risk depends on the AGC subcategory and the patient’s age. AGC-Endocervical (AGC-EC) findings are often associated with high-risk Human Papillomavirus (HPV) strains, particularly HPV-18, and carry a higher risk for endocervical adenocarcinoma. In contrast, Atypical Endometrial Cells (AGC-EM) are strongly linked to endometrial pathology, especially in women over 50. For women with AGC positive for HPV-16 or HPV-18, the two-year cumulative incidence of invasive cervical cancer can be as high as 17 percent, demonstrating the need for aggressive follow-up.
Necessary Follow-up Procedures After an AGC Diagnosis
Because of the elevated risk and the potential for a serious underlying condition, a diagnosis of Atypical Glandular Cells necessitates an immediate and comprehensive diagnostic workup. Unlike some other abnormal Pap results, repeat cytology is not a sufficient initial management strategy. The initial step for nearly all AGC results is a colposcopy, which is a magnified examination of the cervix, vagina, and vulva to identify suspicious areas.
During the colposcopy, the clinician performs an Endocervical Curettage (ECC), taking a tissue sample from the inner cervical canal. This procedure is important because glandular cells originate in the endocervix, a region often not fully visible during the standard colposcopic examination. The deeper location means the source of the abnormality can be missed if only the outer surface of the cervix is biopsied.
An Endometrial Biopsy (sampling of the uterine lining) is also a standard part of the workup for many women with an AGC diagnosis. This is necessary for women over 35, or for younger women with risk factors for endometrial cancer, such as abnormal uterine bleeding. This dual-site sampling determines if the atypical cells originated from the cervix or the uterus. This distinction dictates the subsequent treatment plan to ensure any precancerous or cancerous changes are found and removed.