F-18 FDG PET-CT in a Rare Case of Bartholin's Gland Undifferentiated Carcinoma Managed With Chemoradiation and Interstitial Brachytherapy

PET/CT Variants and Pitfalls in Gynecological Cancers

The role of hybrid imaging with 2-[18F] flourodeoxyglucose (FDG) positron emission tomography and computed tomography (PET/CT) is continuously evolving and now considered standard practice in evaluation of disease stage, treatment response, recurrent disease and follow-up for numerous primary malignancies. In gynecological malignancies FDG PET/CT plays an important role, not only in the assessment of disease in the pre-and post-therapy setting, but also in radiation therapy (RT) planning by defining the metabolically active gross tumor volume (GTV. The glucose analogue radiotracer, FDG, is by far the most utilized radiotracer in PET/CT and is typically seen with high uptake in malignant cells. The radiotracer FDG has a high sensitivity but low specificity for malignancy, as benign processes with an inflammatory response for example infection, are also FDG-avid. In the evaluation of the female pelvic region an awareness of potential confounding factors in the interpretation of FDG is essential as variations of FDG uptake occur in accordance with the menstrual cycle and the menopausal state. Incidental imaging findings in the female genital can pose differential diagnostic challenges as false-positive and false-negative findings in benign and malignant processes are not uncommon. Gynecological malignancies continue to pose major public health problems with cervical cancer as the fourth most common cancer in women ranking after breast cancer, colorectal cancer and lung cancer. Familiarity with frequently encountered benign and malignant variants and pitfalls in FDG PET/CT in the female pelvic region can aid the reader in differential diagnostic considerations.

Solitary Vulvar Involvement of Ovarian Non-Hodgkin Lymphoma Mimicking Bartholin's Abscess on 18F-FDG PET/CT

ABSTRACT

A 49-year-old woman was diagnosed with diffuse large B-cell lymphoma of the left ovary. Two months after the hysterectomy and bilateral salpingo-oophorectomy operation, the patient was referred to 18F-FDG PET/CT for staging. A mass lesion measuring 2.8 × 3 cm with intense 18F-FDG uptake was observed at right labium majus, which could be considered as a Bartholin's cyst or abscess. The lesion was excised, and non-Hodgkin lymphoma involvement of vulva was revealed by histopathology.

Bartholin gland cancer

INTRODUCTION

Bartholin gland carcinoma is an extremely rare condition. Because of its, phase III trials have not been carried out, there exists no unanimous consensus on treatment and guidelines are missing.

METHODS

All studies reporting cases of Bartholin cancer were collected and screened for the evaluations. Baseline characteristics of studies were extracted and were queried in a database.

RESULTS

A total number of 133 manuscripts collected were available for the review process, representing a total number of 275 reported cases. The histological type of Bartholin gland cancer was specified in 90.4% cases: 30.7% cases were squamous cell carcinoma, 29.6% adenoid cystic carcinoma, 25% adenocarcinomas. At multivariate analysis adenocarcinoma histotype and positive lymph node were statistical correlated with worse prognosis.

CONCLUSION

Bartholin gland cancer remains a challenge for gynecologic oncologists. To better understand and treat this disease, centralization to referral centers and design of multi institutional trials is crucial.

The role of FDG-PET/CT in gynaecological cancers

There is now a growing body of evidence supporting the use of fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) in gynaecological malignancies. Although this molecular imaging technique is becoming increasingly available, PET/CT remains an expensive imaging tool. It is essential to be familiar with the circumstances in which FDG-PET/CT can add value and contribute to patient management and indeed to know when it is unlikely to be of benefit. It is also important to understand and recognize the potential pitfalls. FDG-PET/CT has been most widely adopted for staging patients with suspected advanced disease or in suspected recurrence, offering a whole-body imaging approach. However, there is great potential for this technique to act as a predictive biomarker of response to treatment, as well as a prognostic biomarker. In addition, FDG-PET images may now be incorporated into radiotherapy planning in order to refine the delineation of dose according to metabolically active sites of disease. This article reviews the literature that provides the evidence for the use of FDG-PET in gynaecological malignancies, identifies areas of real benefit and future potential, and highlights circumstances where there is limited value.

Gynecological cancers

The clinical problems raised in patients presenting with all forms of gynecological malignancy are currently addressed using conventional cross-sectional imaging, usually MRI. In general, F-18 FDG PET-CT has not been shown to have a clinical role in any of these cancers at presentation, although studies are under way to use this form of metabolic imaging to predict prognosis and the response to treatment. Although F-18 FDG PET-CT is superior to conventional imaging techniques, it is only moderately sensitive in demonstrating lymph node metastasis preoperatively, and is inadequate for local staging of patients with endometrial cancer. In ovarian cancer, F-18 FDG PET-CT provides an accurate assessment of the extent of disease, particularly in areas difficult to assess for metastases by CT and MRI such as the abdomen and pelvis, mediastinum, and supraclavicular region. F-18 FDG PET-CT is a sensitive method of detecting pelvic and para-aortic lymph nodal disease in cervical cancer, and appears to be superior to MRI and CT despite the limitations in identifying small foci of disease. In the main, as elsewhere in patients with cancer, the value of PET-CT is in identifying and defining the extent of recurrent disease, in distinguishing between posttreatment fibrosis and recurrence, and possibly in monitoring response to therapy.