Figures 1 and 2: Sagittal and Axial T2-weighted images demonstrate a large mass (3.8 x 3.7 x 3.1 cm) arising from the posterior cervix that is slightly T2 hyperintense. This mass extends into the posterior vaginal fornix. There is no pelvic lymphadenopathy and both ovaries appear unremarkable.

Figure 3: Axial VIBE image demonstrates enhancement within the cervical mass, which extends to the left vaginal wall without parametrial invasion.

Cervical cancer.

Cervical cancer is the third most common gynecologic malignancy, with an average patient age of onset of 45 years (range 45-55 years of age). Squamous carcinoma accounts for 85-90% of cervical cancers and the remaining histologic types consist of adenocarcinoma (10-15%), adenosquamous carcinomas, adenoid cystic carcinoma, small cell carcinoma, undifferentiated carcinomas, and lymphoma. Risk factors for developing cervical cancer include early sexual activity, multiple sexual partners, low socioeconomic background, multiparity, cigarette smoking, immunosuppression, and infection with human papillomaviruses (HPV) 16 and 18. More than 90% of squamous cell carcinomas of the cervix contain HPV. The clinical features of invasive cervical carcinoma depend on the size of the lesion. The most common clinical symptom is vaginal bleeding.

At histologic examination, the tumor typically appears as cords of neoplastic epithelium that infiltrate the fibrous stroma of the cervix. Cervical cancer can be subdivided into preinvasive, i.e. before transgression of the basement membrane, and invasive lesions. In young women, cervical carcinoma usually originates from the squamocolumnar junction and tends to be more exophytic. However, in older women cervical carcinoma originates more often in the endocervical canal and the bulk of the tumor is centered at the level of the cervix, with either protrusion into the vagina or invasion of the lower myometrium. Cervical cancer spreads by direct extension to contiguous structures, e.g. uterine corpus, vagina, and parametrium, or through lymphatics to regional nodes and rarely via hematogenous route. Adenocarcinomas tend to have a worse prognosis. Other indicators of a poorer prognosis include young age, lymphadenopathy, tumor diameter larger than 4 cm, depth of stromal invasion greater than 5 mm, and advanced stage at presentation.

Accurate tumor staging is crucial for appropriate therapy. The most important issue in staging of cervical cancer is distinguishing early disease that can be treated with surgical resection from more advanced disease that requires radiation and possibly chemotherapy. Cervical cancer is typically staged using the International Federation of Gynecology and Obstetrics (FIGO) classification. The TNM staging classification is essentially based on the same criteria as the FIGO system. The FIGO staging system is based on clinical evaluation, which includes a physical examination under anesthesia involving the inspection and palpation of the pelvic organs and rectum, lesion biopsy, and radiologic examinations such as, chest radiographs, intravenous pyelogram, excretory urography, cystoscopy, protoscopy, sigmoidoscopy and barium enema studies. However, the FIGO staging system has limitations, which when correlated with intraoperative and pathologic findings shows an error rate of 20 to 66% depending on the stage of the disease. These errors arise from the failure to recognize tumor infiltration of the parametrium, pelvic sidewall, or bladder and rectal wall, and metastatic spread. In addition, important prognostic factors such as tumor volume, lymph node metastases and histologic grade are not included in or are not well measured by FIGO staging system. Given the limitations of clinical staging,

extended clinical staging using cross-sectional imaging is incorporated into therapeutic planning for most tumors.

MRI with its superior soft-tissue contrast and multiplanar imaging capabilities is the single best modality for preoperative staging of cervical cancer. MRI also obviates the use of invasive procedures such as cystoscopy and proctoscopy. MRI provides the most benefit in evaluating tumors greater than 2 cm at clinical examination, endocervical lesions, possible parametrial extension, and pregnant patients. On T1-weighted images a cervical neoplasm is isointense with the surrounding cervical tissue. T2-weighted MR sequences highlight not only the normal cervical zonal anatomy (endocervical canal, mucosal folds, fibrocervical stroma, and smooth muscle) but also the primary tumor and its extent. Cervical carcinoma has a relatively high signal intensity at T2-weighted imaging regardless of histopathologic type and is often seen disrupting the low-signal intensity fibrous stroma of the cervix. T2-weighted images are 93% accurate in determining cervical cancer size to within 0.5 cm when using surgical specimens as a gold standard. The utility of gadolinium contrast images for staging of cervical cancer with MRI is not entirely clear. Most studies agree the delayed contrast-enhanced images provide little advantage over noncontrast images unless adjacent organ invasion is suspected. Dynamic gadolinium-enhanced images may be useful for detecting small cervical lesions, detecting or confirming invasion of adjacent organs, and identifying fistulous tracts. Dynamic imaging has also been advocated as an aid in predicting tumor response to radiotherapy. Lymph node disease detection is based solely on a size criterion, the most widely accepted being a transverse diameter exceeding 10 mm.

Okamoto Y, Tanaka YO, et al. MR Imaging of the Uterine Cervix: Imaging-Pathologic Correlation. RadioGraphics. 2003; 23: 425-445. Displayed on website with permission from Y. Okamoto.

Treatment modalities of cervical cancer depend on the stage of the disease and include surgery, radiation therapy, and chemotherapy. The 5-year survival rate for patients in whom cervical cancer is detected early is approximately 91%. The overall survival rate for patients with cervical cancer is 69%.

References:

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3. Okamoto Y, Tanaka YO, et al. MR Imaging of the Uterine Cervix: Imaging-Pathologic Correlation. RadioGraphics. 2003; 23: 425-445.
4. Szklaruk J, Tamm EP, et al. MR Imaging of Common and Uncommon Large Pelvic Masses. RadioGraphics. 2003; 23: 403-424.
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