Primary Cystic Lesions of the Retrorectal Space: MRI Evaluation and Clinical Assessment.

OBJECTIVE: The purpose of this study was to assess the a priori chance that primary cystic lesions of the retrorectal space are malignant and to investigate MRI characteristics that indicate malignancy. MATERIALS AND METHODS: Patients referred to a center for colorectal surgery were recruited from 2000 to 2014. Lesions were proven by clinical assessment and histopathology. MRI was performed at 1.5 T with examinations evaluated by two radiologists. Interobserver agreement was assessed (Cohen kappa) and differences between malignant and benign lesions calculated (Fisher exact test). RESULTS: Twenty-eight patients (22 women, six men; age range, 18-70 years) with 31 lesions were included. Lesions were categorized as tailgut cysts (n = 16, 52%), teratomas (n = 9, 29%), lesions of colorectal origin (n = 4, 13%), or neurogenic lesions (n = 2, 6%). Five patients (18%) had malignant lesions. Colorectal lesions had the highest percentage of malignancy (3/4, 75%). A solid tissue component was found in all five (100%) malignant lesions and two (8%) of the benign lesions, which were both teratomas (p < 0.05). Sensitivity and specificity for malignancy according to the presence of a solid tissue component was 100% (5/5) and 92% (24/26). For unilocularity, multilocularity, debris, septa, and wall thickening, differences were not significant. Interobserver agreement was excellent (κ = 1) for all characteristics except debris (κ = 0.795). CONCLUSION: The majority of retrorectal cystic lesions are benign. The presence of a solid tissue component should raise suspicion for malignancy.

Is bone scintigraphy indicated in surgical work-up for hepatocellular carcinoma patients?

BACKGROUND: Patients with hepatocellular carcinoma (HCC) undergo extensive staging investigations when being assessed for surgical resection. The aim of this study was to assess the use and yield of baseline bone scintigraphy in patients with HCC necessitating high-risk surgical resection. MATERIAL AND METHODS: All patients diagnosed with HCC between 2000 and 2010 within a tertiary referral center were reviewed. Recurrence and survival rates were compared between patients with and without bone scintigraphy in their preoperative work-up. RESULTS: A total of 366 patients were diagnosed with resectable HCC. In the work-up for resection 137 HCC patients (41%) underwent bone scintigraphy, which showed bone metastases in 3 (2%). There was no significant difference in long-term survival between patients with and without bone scintigraphy. None of the patients with a positive bone scintigraphy died due to skeletal bone metastases. Only one patient had an indication for bone scintigraphy based on clinical suspicion. Two patients were found to have asymptomatic skeletal metastases prior to surgery. Symptomatic skeletal metastases were identified at an estimated cost of €27,008 per case. CONCLUSIONS: Clinically unsuspicious bone lesions turned out to be metastases in two patients, with an estimated cost of €27,008 per case. Recurrence rate and disease-free and overall survival showed no significant difference between patients with and without preoperative baseline bone scintigraphy. There is no justification for routine preoperative bone scintigraphy to detect asymptomatic skeletal metastases in patients with resectable HCC.

Comparison of macroscopic pathology measurements with magnetic resonance imaging and assessment of microscopic pathology extension for colorectal liver metastases.

PURPOSE: To compare pathology macroscopic tumor dimensions with magnetic resonance imaging (MRI) measurements and to establish the microscopic tumor extension of colorectal liver metastases. METHODS AND MATERIALS: In a prospective pilot study we included patients with colorectal liver metastases planned for surgery and eligible for MRI. A liver MRI was performed within 48 hours before surgery. Directly after surgery, an MRI of the specimen was acquired to measure the degree of tumor shrinkage. The specimen was fixed in formalin for 48 hours, and another MRI was performed to assess the specimen/tumor shrinkage. All MRI sequences were imported into our radiotherapy treatment planning system, where the tumor and the specimen were delineated. For the macroscopic pathology analyses, photographs of the sliced specimens were used to delineate and reconstruct the tumor and the specimen volumes. Microscopic pathology analyses were conducted to assess the infiltration depth of tumor cell nests. RESULTS: Between February 2009 and January 2010 we included 13 patients for analysis with 21 colorectal liver metastases. Specimen and tumor shrinkage after resection and fixation was negligible. The best tumor volume correlations between MRI and pathology were found for T1-weighted (w) echo gradient sequence (r(s) = 0.99, slope = 1.06), and the T2-w fast spin echo (FSE) single-shot sequence (r(s) = 0.99, slope = 1.08), followed by the T2-w FSE fat saturation sequence (r(s) = 0.99, slope = 1.23), and the T1-w gadolinium-enhanced sequence (r(s) = 0.98, slope = 1.24). We observed 39 tumor cell nests beyond the tumor border in 12 metastases. Microscopic extension was found between 0.2 and 10 mm from the main tumor, with 90% of the cases within 6 mm. CONCLUSIONS: MRI tumor dimensions showed a good agreement with the macroscopic pathology suggesting that MRI can be used for accurate tumor delineation. However, microscopic extensions found beyond the tumor border indicate that caution is needed in selecting appropriate tumor margins.