Table 2  MRI staging of vaginal cancer

Stage MRI findings

ITumor confined within the vagina, with preservation of the low T2 signal of the vaginal wall

IIDisruption of the low T2 signal of the vaginal wall, abnormal low T1 signal in the paravaginal fat

IIITumor spread within 3 mm of the internal obturator, levator ani, or piriformis muscles and/or iliac vessels. Increased T2 signal of the musculature and/or direct invasion of the tumor

aortic chain, the middle third into the common and internal iliac chains, and the lower third into the superficial inguinal, femoral, and perirectal nodal chains. However, these patterns of lymphatic drainage are highly variable and unreliable (Gardner et al. 2015). Both CT and MRI may be used for the evaluation of metastatic lymphadenopathy.

6.1.1.3\ Recurrence and Complications

Local recurrences in vaginal cancer are the most common, usually seen within the first few years after initial diagnosis, almost 80% by 2 years and 90% by 5 years. The stage of the disease has been proved to be the main predictive variable for recurrence, reported to occur at 24% of cases for stage I disease, up to 73–83% of cases for stage IV disease. Tumors of the upper third of the vagina tend to recur locally, whereas those of the lower third are more often associated with pelvic sidewall invasion or even distant recurrence. In patients with recurrence, 5-year survival rate is poor, approximating 12% (Gardner et al. 2015; Parikh et al. 2008). MRI is useful in staging patients with vaginal carcinoma recurrence, with an overall accuracy of 82–95% (Gardner et al. 2015).

Common posttreatment complications in patients with vaginal carcinoma include radi- ation-induced bladder, rectal, and vaginal toxicity. Complications usually occur within the first 5 years of treatment, but may be seen up to 20 years later. FIGO stage, tumor size, and total radiation dose predict higher likelihood of complications. On imaging, post-radiation complications are common, reported in up to 30% of patients, with rectovaginal and vesicovaginal fistulas seen in 21%. Cystitis, proctitis, bowel stricture and perforation, pelvic bone osteonecrosis, and stress fractures may also occur. Various imaging modalities can be used to assess complications, including MRI (Gardner et al. 2015; Parikh et al. 2008).

6.1.2\ Non-squamous Cell Carcinomas of the Vagina

Non-squamous cell carcinomas account for 15% of all primary vaginal carcinomas. These tumors usually are diagnosed at early stage, in younger age, and have better prognosis. However, they are more likely to recur than SCCs, often within 1–7 years after the diagnosis of primary tumor (Parikh et al. 2008; Tsuda et al. 1999).

6.1.2.1\ Adenocarcinoma

Adenocarcinomas account for 9% of primary vaginal malignancies. The mean age at diagnosis is 19 years; two-thirds of those women have a history of exposure to diethylstilbestrol in utero, dating from the 1950–1970s, when diethylstilbestrol was given to mothers at risk for miscarriage. Primary vaginal adenocarcinoma mainly involves the upper third and the anterior wall of the vagina. On MRI, it appears either as a bulky lobulated vaginal mass, hyperintense on T2WI or as diffuse circumferential thickening of the vaginal wall (Parikh et al. 2008; Tsuda et al. 1999).

6.1.2.2\ Melanoma

Primary vaginal malignant melanoma accounts for less than 3% of all vaginal malignancies. Only less than 0.5–2% of all melanomas in women affect the vagina, the vulva representing the commonest site. It often manifests in postmenopausal women, with a predilection for the lower vaginal third and the anterior and lateral

Fig. 15  FIGO stage II vaginal melanoma. (a) Sagittal T2WI depicts heterogeneous vaginal tumor (arrow), mainly hyperintense. Area of necrosis is detected within the mass with very high signal intensity and a small

amount of air (long arrow). Axial T1WI shows vaginal neoplasm extending into the paravaginal tissues (b, arrow). An enlarged left internal iliac node (c, long arrow) is also seen (Courtesy Dr. Forstner R, Salzburg, Austria)

walls. MRI features­ are variable. These tumors may present with typical high T1 signal and low T2 signal, due to the paramagnetic effects of melanin and methemoglobin from intratumoral necrosis or hemorrhage. Amelanotic melanomas may appear with low T1 signal and intermediate to high T2 signal (Fig. 15). Melanomas are much more easily detected on fat-suppressed T1WI with brighter signal, as the dynamic range becomes narrower, allowing detection of subtle differences (López et al. 2005; Parikh et al. 2008; Tsuda et al. 1999; Moon et al. 1993).

6.1.2.3\ Sarcomas

Sarcomas account for less than 3% of primary vaginal malignancies. Primary vaginal leiomyosarcoma­ represents the commonest

vaginal soft-tissue sarcoma in adults. The average age is 50 years and may occur after radiation therapy to the genital tract. This tumor is thought to originate from the rectovaginal septum, mainly involving the upper vagina. Early hematogenous spread and local recurrence frequently occurs. MRI usually shows a bulky cystic-solid mass arising from the vagina, with areas of high T2 signal corresponding to cystic necrosis and pockets of high T1 signal corresponding to acute hemorrhage, strongly and heterogeneously enhancing (Fig. 16) (Griffin et al. 2010; Parikh et al. 2008).

6.1.2.4\ Lymphoma

Primary lymphoma of the vagina is rare, representing approximately 1% of primary extranodal lymphomas. Secondary lymphoma is more

Fig. 16  FIGO stage III vaginal leiomyosarcoma. Axial (a) T2WI, (b) post-gadolinium fat-suppressed T1WI, and (c) ADC map demonstrate a large, heterogeneous vaginal mass, with strong, inhomogeneous contrast enhancement,

and restricted diffusion. The neoplasm is in direct contact with the right internal obturator muscle (arrowhead), a finding suggestive of pelvic sidewall invasion (Courtesy Dr. Forstner R, Salzburg, Austria)

common­ . Both are usually B-cell, non-Hodg- kin’s lymphomas. The mean age at presentation is 50 years. The tumor is infiltrative or mass-like of homogeneous low T1 signal and intermediate- to-high T2 signal. Homogeneous enhancement is seen after intravenous contrast medium administration. An intact mucosa is considered characteristic for the diagnosis of lymphoma (Griffin et al. 2010; McNicholas et al. 1994).

6.1.3\ Secondary Vaginal

Malignancies

Secondary malignancies of the vagina are far more common than primary tumors and account for more than 80% of all vaginal neoplasms. The majority of vaginal metastases occur through direct contiguous spread from malignancies of

adjacent tumors, e.g., primary cervical (Fig. 17), endometrial, vulval, rectal, or bladder carcinoma. Distant vaginal metastases may occur through lymphatic or hematogenous spread. The most common malignancies to metastasize to the vagina are ovarian, cervical, endometrial (Fig. 18), and rectal cancer. Very rarely, extragenital cancers including adenocarcinoma of the colon (Fig. 19), breast, pancreas, and small bowel may metastasize to the vagina. The vagina can also be the site for local recurrence, e.g., from endometrial and cervical carcinoma. The majority (80%) of vaginal metastases occur within the first three years after the diagnosis of primary malignancy, and 67% occur after surgical removal of the primary lesion. Disseminated metastatic disease is often present in patients