ASC-US

The Bethesda system (TBS) is a system for reporting cervical or vaginal cytologic diagnoses, used for reporting Pap smear results. It was introduced in 1988, and revised in 1991 and 2001. The name comes from the location (Bethesda, Maryland) of the conference that established the system.

Additionally, the Bethesda System is used for thyroid cytopathology.

Abnormal results include:

The results are calculated differently following fine needle aspiration of thyroid nodules.

Low-grade squamous intraepithelial lesion (LSIL or LGSIL) indicates possible cervical dysplasia. LSIL usually indicates mild dysplasia (CIN 1), more than likely caused by a human papillomavirus infection. It is usually diagnosed following a Pap smear.

CIN 1 is the most common and most benign form of cervical intraepithelial neoplasia and usually resolves spontaneously within two years. Because of this, LSIL results can be managed with a simple "watch and wait" philosophy. However, because there is a 12–16% chance of progression to more severe dysplasia, the physician may want to follow the results more aggressively by performing a colposcopy with biopsy. If the dysplasia progresses, treatment may be necessary. Treatment involves removal of the affected tissue, which can be accomplished by LEEP, cryosurgery, cone biopsy, or laser ablation.

High-grade squamous intraepithelial lesion (HSIL or HGSIL) indicates moderate or severe cervical intraepithelial neoplasia or carcinoma in situ. It is usually diagnosed following a Pap test. In some cases these lesions can lead to invasive cervical cancer, if not followed appropriately.

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