Benign and Malignant Ovarian Teratomas: Multimodality Imaging Findings With Histopathologic Correlation.

ABSTRACT: The purpose of this article is to provide a comprehensive review of the imaging findings along with histopathologic correlation of mature (benign) teratomas and malignant ovarian teratomas, which include both immature teratomas and malignant degeneration of mature teratomas. The radiologist's ability to provide an accurate diagnosis plays an essential role in guiding the interdisciplinary care of patients with malignant teratomas and improving their outcomes.

Metastatic ovarian carcinosarcoma in a patient undergoing in-vitro fertilization: A case report.

INTRODUCTION AND IMPORTANCE: Ovarian carcinosarcomas (OCS) are highly aggressive tumors containing both carcinomatous and sarcomatous elements. Patients are typically older postmenopausal women who present with advanced disease, however rarely young women can be affected. CASE PRESENTATION: A 41-year-old woman undergoing fertility treatment was found to have a new 9-10 cm pelvic mass on routine transvaginal ultrasound (TVUS) 16 days after embryo transfer. Diagnostic laparoscopy revealed a mass in the posterior cul-de-sac that was surgically excised and sent to pathology for evaluation. Pathology was consistent with carcinosarcoma of gynecologic origin. Further work-up revealed advanced disease with apparent rapid progression. Patient underwent interval debulking surgery after four cycles of neoadjuvant chemotherapy with carboplatin and paclitaxel with final pathology consistent with primary ovarian carcinosarcoma and complete gross resection of disease. CLINICAL DISCUSSION: In the setting of advanced disease neoadjuvant chemotherapy with a platinum-based chemotherapy regimen followed by cytoreductive surgery is a standard approach to treatment of OCS. Given the rarity of disease, most data regarding treatment has been extrapolated from other forms of epithelial ovarian cancer. Specific risk factors for disease development of OCS including the long-term effects of assisted reproductive technology remain understudied. CONCLUSION: While OCS are rare highly aggressive biphasic tumors that primarily affect older postmenopausal woman, we present a unique case of OCS incidentally found in a young woman undergoing fertility treatment via in-vitro fertilization.

Regional trends of minimally invasive radical hysterectomy for cervical cancer and exploration of perioperative outcomes.

INTRODUCTION: Radical hysterectomy (RH) with bilateral pelvic lymph node dissection is the standard treatment for early stage cervical cancer which can be performed either by an abdominal or a minimally invasive (MIS) approach. In 2018, Ramirez et al. presented their randomized-controlled trial data which demonstrated that patients who were treated with minimally invasive surgical (MIS) radical hysterectomy (RH) had higher rates of locoregional disease recurrence and lower rates of overall survival when compared to patients treated with an abdominal approach. The objective of this study is to examine the trends in management of patients diagnosed with cervical cancer in New York State (NYS) and to analyze their perioperative outcomes. METHODS: Using the Statewide Planning and Research Cooperative System (SPARCS) Database, patients undergoing RH for early stage cervical cancer in NYS between the years of 2007-2015 were identified and categorized based on surgical approach. Demographic information was collected and multivariable regression was conducted to assess the impact of hysterectomy approach on perioperative outcomes. RESULTS: In NYS, 5575 patients were treated with RH for early stage cervical cancer with 3257 (58.4%) treated by abdominal RH and 2318 (41.6%) treated with MIS RH. Between the years of 2007 and 2015, patients diagnosed with cervical cancer treated with MIS RH increased from 25.7% to 48.3% respectively. Surgeons performing MIS RH were more likely to be younger (average age 47.1 vs 49.2, p < 0.001) and have less time elapsed from their fellowship graduation (20.37 vs 22.64 years, p < 0.001). Patients who saw high volume doctors (OR 1.95, CI 1.65-2.31) and were seen in high volume facilities (OR 1.40, CI 1.18-1.65) were more likely to undergo MIS RH compared to abdominal RH. Patients who underwent MIS RH were more likely to be discharged home as opposed to acute rehab or nursing facility, when compared to patients treated with abdominal RH (98.5 vs 94.2% p < 0.001). When analyzing perioperativce outcomes, patient undergoing MIS RH had a 85% decrease in length of hospital stay compared to abdominal RH, a 40% reduction in 30-day readmission rates, and a 10% reduction in hospital costs respectively. DISCUSSION: In our study period, between the years of 2007 and 2015, the number of cervical cancer cases treated with MIS RH increased from 25.7% to 48.3%. MIS techniques led to a reduction in length of hospital stay, patient readmission rates, and hospital costs. Based on recent data from Ramirez et al., preliminary data demonstrated decrease in MIS RH for treatment of cervical cancer after presentation of the LACC trial and our data confirmed these reported trends in NYS. With this change in surgical practice, there will be associated changes in perioperative outcomes. Moreover, for patients diagnosed with cervical cancer with microscopic disease or previous treatment with an excisions procedure, MIS approach should be considered for improvement in perioperative outcomes as long as oncologic outcomes are not compromised.

Variability in the identification of lymphovascular space invasion for early stage cervical cancer.

OBJECTIVE: To evaluate the inter- and intra-rater variability of lymphovascular space invasion (LVSI) in early stage cervical cancer. METHODS: We identified invasive cervical cancer tissue samples from radical hysterectomies in our institutional pathology database. The cases were stained with Hematoxylin & Eosin (H&E) and immunostains (CD-31 and D2-40). They were evaluated for the presence of LVSI by 6 pathologists on 3 separate occasions: with H&E staining only, then with H&E and immunostained specimens, and finally using a shared written criterion for diagnosis of LVSI. With 80 cases, a two-sided 95% confidence interval for the Kappa of 0.7 with a precision of 0.1 on each side was estimated. RESULTS: Stage distribution was: IA 10%, IB 85%, and IIA 5%. The majority of cases were squamous cell carcinoma (55%), followed by adenocarcinoma (39%) and adenosquamous or other histology (6%). The mean inter-rater Kappa was 0.41 (95% CI: 0.37-0.45) for H&E. Usage of immunohistochemistry made a statistically significant improvement in the mean Kappa, but it still remained low: 0.52 (p = 0.02). Adding evaluation criteria for LVSI did not significantly increase the mean Kappa: 0.49 (p = 0.16). The mean intra-rater variability of H&E staining alone compared with H&E staining plus immunostaining was 0.53 (range: 0.43-0.64). The mean Kappa comparing H&E staining and H&E staining with criteria was 0.50 (range: 0.40-0.59). CONCLUSIONS: We noted high inter- and intra-rater variability in the diagnosis of LVSI underscoring the challenges of LVSI diagnosis. Considering the significance assigned to LVSI and its implication for treatment, comprehensive guidelines with regards to determination of LVSI status are of paramount importance.

Tumor immune microenvironment in brain metastases from gynecologic malignancies.

INTRODUCTION: The density and distribution of the tumor immune microenvironment associated with brain metastases (BM) from gynecologic malignancies are unknown and have not been previously reported. We sought to describe the clinical features of a cohort of patients with BM from gynecologic malignancies and to characterize the tumor immune microenvironment from available archival surgical specimens. METHODS: We performed a retrospective review of electronic medical records from 2002 to 2018 for patients with BM from gynecologic malignancies. Data on patient characteristics, treatment regimens, and clinical outcomes were procured. CD4, CD8, CD45RO, CD68, CD163, and FOXP3 immunohistochemistry were evaluated from available archival surgical specimens from primary disease site and neurosurgical resection. RESULTS: A cohort of 44 patients with BM from gynecologic malignancies was identified, 21 (47.7%) endometrial primaries and 23 (52.3%) ovarian primaries. Tumor-infiltrating lymphocytes (TILs) and tumor-associated macrophages (TAMs) were evaluated in 13 primary cases and 15 BM cases. For the 13 primary cases, CD4+ TILs were evident in 76.9% of cases, CD8+ in 92.3%, CD45RO+ in 92.3%, and FOXP3+ in 46.2%, as well as CD68+ TAMs in 100% and CD163+ in 100%. For the 15 BM cases, CD4+ TILs were evident in 60.0% of cases, CD8+ in 93.3%, CD45RO+ in 73.3%, and FOXP3+ in 35.7%, as well as CD68+ TAMs in 86.7% and CD163+ in 100%. CONCLUSION: An active tumor immune microenvironment is present with similar distribution in the primary disease site and BM from patients with gynecologic malignancies.

Feasibility and diagnostic performance of hybrid PET/MRI compared with PET/CT for gynecological malignancies: a prospective pilot study.

PURPOSE: The purpose of the study was to assess the feasibility and diagnostic performance of FDG-PET/MR imaging compared to PET/CT for staging of patients with a gynecological malignancy. METHODS: 25 patients with a gynecological malignancy were prospectively enrolled into this pilot study. Patients underwent sequential full-body PET/CT and PET/MR of the abdomen and pelvis after administration of a single dose of F-18 FDG. PET/MRI and PET/CT images were independently reviewed by two expert radiologists. Readers were blinded to the results of the other imaging procedures. Clinical and pathologic information was abstracted from medical charts. RESULTS: 18 patients were included in the final analysis with a median age of 62 years (range 31-88). 61% of patients (11/18) had cervical cancer, while the remaining patients had endometrial cancer. PET/MRI as compared to PET/CT detected all primary tumors, 7/7 patients with regional lymph nodes, and 1/1 patient with an abdominal metastasis. Two patients had additional lymph nodes outside of the abdominopelvic cavity detected on PET/CT that were not seen on PET/MRI, whereas 6 patients had parametrial invasion and one patient had invasion of the bladder seen on PET/MRI not detected on PET/CT. Five cervical cancer patients had discordant clinical vs. radiographic staging based on PET/MRI detection of soft tissue involvement. Management changed for two patients who had clinical stage IB1 and radiographic stage IIB cervical cancer. CONCLUSIONS: PET/MRI is feasible and has at least comparable diagnostic ability to PET/CT for identification of primary cervical and endometrial tumors and regional metastases. PET/MRI may be superior to PET/CT for initial radiographic assessment of cervical cancers.

Laparoscopic Assessment to Determine the Likelihood of Achieving Optimal Cytoreduction in Patients Undergoing Primary Debulking Surgery for Ovarian, Fallopian Tube, or Primary Peritoneal Cancer.

OBJECTIVE: The objective of this study was to evaluate the safety and efficacy of laparoscopic assessment to determine the likelihood of achieving optimal cytoreduction (OC) in patients undergoing primary debulking surgery (PDS) for ovarian cancer. METHODS: All patients who underwent diagnostic laparoscopy and PDS at our institution from January 2008 to December 2013 were identified. We determined the likelihood of achieving optimal cytoreduction by laparoscopic assessment based on tumor site, pattern of spread, and disease burden. Sensitivity was defined as the number of patients who achieved optimal cytoreduction after laparoscopic assessment divided by the number of patients with disease deemed resectable by laparoscopy. RESULTS: We identified 55 patients during study period. Twenty-one of the 55 patients (38%) were early stage disease. Six (10.9%) patients had disease deemed unresectable and 49 (89.1%) had disease deemed resectable at the time of laparoscopy. OC was achieved in 48 of 49 (97.9%) patients. The sensitivity of laparoscopy in predicting OC was 98% (95% confidence interval, 89.3%-99.9%). The operation was completed laparoscopically in 23 of 49 patients (47%); in 26 of 49 (53%), PDS was performed by laparotomy. There were no port site metastases reported. The rate of postoperative complications was 16%. With a median follow-up of 30 months, the median overall survival was not reached and the 75th percentile for overall survival was 37 months. CONCLUSIONS: Laparoscopy was shown to have a high sensitivity in predicting OC and is a feasible tool in triaging patients with ovarian cancer. Laparoscopy is not associated with adverse surgical outcomes.

Heterotopic Pregnancy Including Intrauterine Normal Gestation and Tubal Complete Hydatidiform Mole: A Case Report and Review of the Literature.

We report a rare case of heterotopic pregnancy with intrauterine normal gestation alongside tubal complete hydatidiform mole (CHM) that resulted in a viable pregnancy after removal of molar tissue. Because of their rarity and inherent complexity, such cases represent a significant challenge in diagnosis and management. A 34-year-old female in her 10th week of gestation presented with nausea, vomiting, and intermittent abdominal pain that progressively worsened. Imaging studies revealed a normal intrauterine fetus and an 11-cm heterogenous mass in the left adnexal region. The patient's serum human chorionic gonadotropin was higher than the reference range. Diagnostic laparoscopy revealed a large hemorrhagic mass involving the left adnexa that was removed completely. The mass was composed of blood clots admixed with necrotic tissue of vesicular appearance on gross inspection. Microscopic examination revealed large chorionic villi with circumferential trophoblastic proliferation and cisterns, all of which are characteristic of CHM. An implantation site was identified at the tubal fimbriae. Immunohistochemistry p57 demonstrated negative staining in the villous stromal and cytotrophoblastic cells, supporting the diagnosis of CHM. Chromosomal karyotyping and cytogenetic analysis were performed on chorionic villi samples from the intrauterine gestation and reported as normal (46, XX). The patient elected to continue the intrauterine pregnancy, delivering a healthy female infant at 39 weeks. Our case reaffirms that to successfully manage this rare yet life-threatening condition, heterotopic pregnancy should be included in the differential diagnosis for any gravid women presenting with persistent abdominal pain and/or extrauterine mass.

Squamous cell carcinoma of the vulva arising in the setting of chronic hidradenitis suppurativa: A case report.

•Highlights the sheer mass of tumor encountered with hidradenitis suppurativa.•Reviews the complexity of wound healing with hidradenitis suppurativa.•Overview of multi-team approach to a vulvar cancer.

Survey of Current Practice Patterns in the Treatment of Early-Stage Endometrial Cancer.

OBJECTIVES: Our aim was to assess current surgical practices and use of adjuvant therapy in the treatment of FIGO (International Federation of Gynecology and Obstetrics) stage I endometrioid endometrial cancer. METHODS: A 19-question survey was developed and sent to all Society of Gynecologic Oncologist members by e-mail. Data were collected anonymously using Internet-based survey software. Respondents were asked questions regarding preoperative evaluation, surgical approach, lymph node dissection (LND), and adjuvant therapy. RESULTS: A total of 1399 surveys were distributed, 320 (23%) members completed the survey. Ninety-seven percent of respondents were gynecologic oncologists or fellows, and 87% treat 30 or more endometrial cancer patients yearly. Respondents were more likely to order preoperative tests such as computed tomography abdomen/pelvis and CA-125 for biopsy-proven grade 3 disease versus grade 1 (82% vs 29%). Robot-assisted laparoscopy was the preferred surgical approach (66%), followed by conventional laparoscopy (21%). Twenty-six percent of respondents perform LND in all cases. Forty-eight percent describe their LND as complete, to the level of the inferior mesenteric artery. Adjuvant therapy was recommended more often with increasing myometrial invasion, tumor grade, and lymphovascular space invasion. Vaginal brachytherapy was the most commonly recommended adjuvant therapy for stage IA. For stage IB, grade 3, positive lymphovascular space invasion disease, respondents were more likely to combine vaginal brachytherapy with external beam radiotherapy and/or chemotherapy. Older patients were more likely to have adjuvant therapy in earlier stages of disease than younger patients. CONCLUSIONS: Our findings demonstrate that respondents are individualizing care based on preoperative, intraoperative, and pathologic findings. As expected, adjuvant treatment is recommended for patients with higher stage and grade disease. Robot-assisted hysterectomy and chemotherapy are now commonly used in the management of this disease. We anticipate that new trends will continue to emerge as results from additional studies become available.

Bevacizumab-induced transient sixth nerve palsy in ovarian cancer: A case report.

We report a case of transient sixth nerve palsy after systemic administration of bevacizumab. Two days after systemic administration of bevacizumab in conjunction with gemcitabine and carboplatin in a 67-year-old woman with recurrent primary ovarian cancer, the patient developed sixth nerve palsy. After bevacizumab was stopped, the complete left sixth nerve palsy resolved spontaneously over the course of 3 months. This is the first reported case of bevacizumab-induced cranial sixth nerve palsy in the treatment of gynecologic malignancy.

Personalized Circulating Tumor DNA Biomarkers Dynamically Predict Treatment Response and Survival In Gynecologic Cancers.

BACKGROUND: High-grade serous ovarian and endometrial cancers are the most lethal female reproductive tract malignancies worldwide. In part, failure to treat these two aggressive cancers successfully centers on the fact that while the majority of patients are diagnosed based on current surveillance strategies as having a complete clinical response to their primary therapy, nearly half will develop disease recurrence within 18 months and the majority will die from disease recurrence within 5 years. Moreover, no currently used biomarkers or imaging studies can predict outcome following initial treatment. Circulating tumor DNA (ctDNA) represents a theoretically powerful biomarker for detecting otherwise occult disease. We therefore explored the use of personalized ctDNA markers as both a surveillance and prognostic biomarker in gynecologic cancers and compared this to current FDA-approved surveillance tools. METHODS AND FINDINGS: Tumor and serum samples were collected at time of surgery and then throughout treatment course for 44 patients with gynecologic cancers, representing 22 ovarian cancer cases, 17 uterine cancer cases, one peritoneal, three fallopian tube, and one patient with synchronous fallopian tube and uterine cancer. Patient/tumor-specific mutations were identified using whole-exome and targeted gene sequencing and ctDNA levels quantified using droplet digital PCR. CtDNA was detected in 93.8% of patients for whom probes were designed and levels were highly correlated with CA-125 serum and computed tomography (CT) scanning results. In six patients, ctDNA detected the presence of cancer even when CT scanning was negative and, on average, had a predictive lead time of seven months over CT imaging. Most notably, undetectable levels of ctDNA at six months following initial treatment was associated with markedly improved progression free and overall survival. CONCLUSIONS: Detection of residual disease in gynecologic, and indeed all cancers, represents a diagnostic dilemma and a potential critical inflection point in precision medicine. This study suggests that the use of personalized ctDNA biomarkers in gynecologic cancers can identify the presence of residual tumor while also more dynamically predicting response to treatment relative to currently used serum and imaging studies. Of particular interest, ctDNA was an independent predictor of survival in patients with ovarian and endometrial cancers. Earlier recognition of disease persistence and/or recurrence and the ability to stratify into better and worse outcome groups through ctDNA surveillance may open the window for improved survival and quality and life in these cancers.

Pilonidal cyst of the clitoris.

A pilonidal cyst is an epithelialized sinus tract or cyst containing hair follicles with a surrounding inflammatory reaction. It usually develops in the sacrococcygeal region with few reports of its development in the genitalia. We present a case of a periclitoral pilonidal cyst in a young woman and its management.

Multicystic benign cystic mesothelioma presenting as a pelvic mass.

Background. Benign cystic mesothelioma (BCM) is a rare tumor that arises from the abdominal peritoneum with a predilection to the pelvic peritoneum. For this reason, it can often mimic gynecologic malignancies. Case. A 47-year-old perimenopausal female presented reporting several weeks of abdominal distention associated with abdominal tenderness and constipation. Computed tomography revealed a 24 cm multiloculated pelvic mass, and tumor markers were notable for an elevated CA-125. The patient was taken to the operating room for an exploratory laparotomy, total abdominal hysterectomy, bilateral salpingoophorectomy, and removal of pelvic mass. Final pathologic evaluation revealed a benign cystic mesothelioma. Conclusion. Classically these tumors present as large multicystic masses with thin-walled septations and on preoperative evaluation BCM can mimic many different disease entities including ovarian malignancies and cystic lymphangioma. Often diagnosis can only be made at time of surgery.

The role of liver resection at the time of secondary cytoreduction in patients with recurrent ovarian cancer.

OBJECTIVE: The aim of this study is to determine the role of liver metastatectomy in the morbidity and survival of patients with recurrent ovarian carcinoma. METHODS: We retrospectively reviewed the records of all patients who had undergone hepatic resection for liver metastases from ovarian carcinoma at the time of cytoreductive surgery at our institution from 1988 to 2012. The Kaplan-Meier method was used for survival analysis. A total of 76 patients met the inclusion criteria and had undergone liver resection as part of cytoreductive surgery for ovarian carcinoma during the study period. Of these 76 patients, 27 underwent liver resection at the time of secondary cytoreduction, and these patients that are the focus of this analysis. RESULTS: Median overall survival for the study group from the time of diagnosis to the last follow-up or death was 56 months (range, 12-249 months). Twenty died of the disease with an overall median survival of 12 months from the time of the liver resection (2-190 months), and 7 patients were alive with the disease at the time of the last follow-up. Based on Kaplan-Meier survival analysis, the factors associated with the longest survival after the liver resection (2-190 months) were the interval from the primary surgery of less than 24 months versus more than 24 months (P = 0.044) and secondary cytoreduction to residual disease of less than 1 cm (P = 0.014). CONCLUSIONS: Based on our analysis of a single institution's series of ovarian cancer patients with hepatic metastasis, liver resection is feasible and safe and should be considered as an option in selected patients at the time of secondary cytoreduction.

Five-millimeter balloon trocar site herniation: report of two cases and review of literature.

Trocar site herniation is a well-known potential complication of minimally invasive surgery. We present the cases of two herniations after use of 5-mm non-bladed balloon trocars. In both patients, surgical management was required, with no subsequent sequelae to date. The hernias were attributed to excessive fascial stretching and compression by the balloon. We recommend full-thickness closure of 5-mm ports if a balloon is used or if there was extensive intraoperative manipulation.

Does the type of surgery for early-stage endometrial cancer affect the rate of reported lymphovascular space invasion in final pathology specimens?

OBJECTIVE: Laparoscopically assisted vaginal hysterectomy (LAVH), which usually involves the use of an intrauterine manipulator for optimal surgical control, has been shown to be as effective and safe as conventional total abdominal hysterectomy (TAH) for the staging of endometrial carcinoma. The purpose of this study was to determine whether the use of an intrauterine manipulator was associated with an increase in the pathologic reporting of lymphovascular space invasion (LVSI), which is an important determinant in choosing adjuvant therapy. We hypothesized that intracavitary manipulation and an increase of the intrauterine pressure could cause pseudolymphovascular invasion. STUDY DESIGN: We performed a retrospective chart review of endometrial cancer patients treated at our institution from January 1996 through January 2006. Records were reviewed for patient's age, preoperative diagnosis, procedure type, final surgical staging, and final pathology report. Using the 2009 International Federation of Gynecology and Obstetrics staging, we included all patients having stage IA or IB endometrioid-type endometrial cancer who had undergone either a TAH or LAVH with or without pelvic and paraaortic lymph node dissection. The χ2 and Fisher exact tests were used to measure the association between risk of positive lymphovascular invasion and surgical groups. RESULTS: Of 568 women identified as having endometrioid-type endometrial cancer, 486 (85.6%) met criteria for stage IA-IB endometrioid histology, grade 1, 2, or 3. LVSI was reported in 553/568 cases, with LVSI positivity in 16.9% (n = 96/568). The mean ages of the LAVH and TAH groups were significantly different (59.4 vs 62.4 years, respectively, P = .0050). Also, mean estimated blood loss and uterine weight significantly varied between TAH and LAVH groups (P = .0001 and .008, respectively). For stage IA, 17/220 (7.7%) who had been treated with LAVH had positive LVSI compared with 20/199 (10.1%) of patients receiving TAH (P = .73). For stage IB, 11/25 (44.0%) of patients treated with LAVH had positive LVSI compared with 10/31 (32.3%) of patients receiving TAH (P = .53). The stage I cancer patients were further subdivided into histological grades 1, 2, and 3, and LVSI was not significantly different between TAH and LAVH groups per grade of cancer. We found no differences between TAH and LAVH in early-stage endometrial cancer (stage IA and IB), with respect to the presence of positive peritoneal washings. CONCLUSION: In early-stage endometrial cancer (stage IA and IB), there were no differences between TAH and LAVH in the final pathologic report of LVSI. The use of an intrauterine manipulator for LAVH was not associated with an increased detection of LVSI.

PET/CT evaluation of cervical cancer: spectrum of disease.

The prognosis of invasive cervical cancer is based on the stage, size, and histologic grade of the primary tumor and the status of the lymph nodes. Assessment of disease stage is essential in determining proper management in individual cases. In the posttherapy setting, the timely detection of recurrence is essential for guiding management and may lead to increased survival. However, the official clinical staging system of the International Federation of Gynecology and Obstetrics has inherent flaws that may lead to inaccurate staging and improper management. Combined positron emission tomography (PET)/computed tomography (CT) represents a major technologic advance, consisting of two integrated complementary modalities whose combined strength tends to overcome their respective weaknesses. PET/CT has higher sensitivity and specificity than do conventional anatomic modalities and is valuable in determining the extent of disease and detecting recurrent or residual tumor. The combination of 2-[fluorine-18]fluoro-2-deoxy-d-glucose PET with intravenous contrast material-enhanced high-resolution CT has proved useful for avoiding the interpretative weaknesses associated with either modality alone and in increasing the accuracy of staging or restaging. Nonetheless, accurate PET/CT interpretation requires a knowledge of the characteristics of disease spread or recurrence and an awareness of various imaging pitfalls if false interpretations are to be avoided.