Early-stage sigmoid colon cancer resection followed by liver metastasis recurrence 1 year later and mesenteric recurrence more than 5 years later: a case report

BACKGROUND

Early-stage colorectal cancer (CRC) is often treated endoscopically, but additional surgical resection may be considered depending on pathological findings.

CASE PRESENTATION

A 73-year-old man was found to have early-stage sigmoid colon cancer by colonoscopy during a medical examination, and endoscopic mucosal resection (EMR) was performed. The lesion was a 7-mm-sized sessile polyp, and the pathological diagnosis was well-differentiated tubular adenocarcinoma, pT1 (submucosal invasion of 400 μm), with no lymphovascular invasion, low budding grade, and negative horizontal and vertical margins. Therefore, the patient was observed without postoperative treatment. One year later, a computed tomography (CT) scan showed multiple liver metastases. After five courses of preoperative chemotherapy with folinic acid, 5-fluorouracil and oxaliplatin (FOLFOX) and panitumumab, liver metastases were reduced. The patient underwent extended right hepatic lobectomy. The pathological finding was well-to-moderately differentiated tubular adenocarcinoma, and immunohistochemistry findings were consistent with liver metastases from sigmoid colon cancer. Postoperatively, the patient received five courses adjuvant chemotherapy with FOLFOX. Although the patient had been recurrence-free for 5 years after liver resection, a CT scan revealed a nodular lesion in the sigmoid mesentery. Positron emission tomography (PET) showed abnormal accumulation in the same lesion. Therefore, the mesenteric nodules diagnosed as lymph metastasis and recurrence of sigmoid colon cancer and performed laparoscopic sigmoid colon resection with lymph node dissection. The pathological findings showed that the recurrent lesion in the mesentery formed a nodular infiltrate with venous, lymphatic, and neural invasion, but lymph node structures were not found, and it was assumed to be metastasis or recurrence due to lymphovascular invasion. The pathologic specimen of the sigmoid colon had no neoplastic lesions, which are considered to be a local recurrence on the mucosal surface. After sigmoid colectomy, adjuvant chemotherapy with CapeOX was conducted, and the patient has been recurrence-free for 13 months at present.

CONCLUSION

Even early-stage CRCs that have no pathological indications for additional resection have risks of metastases and recurrences, and we may need to consider that the criteria for additional resection should not be limited to pathological findings alone.

Characterization of tumor remnants in intraoperative MRI-assisted microscopic and endoscopic transsphenoidal resection of less invasive pituitary adenomas

INTRODUCTION

Intraoperative magnetic resonance imaging (iMRI) improves the intraoperative detection of adenoma remnants in transsphenoidal surgery. iMRI might be redundant in endoscopic pituitary surgery in non-invasive tumors (Knosp 0-2) due to a superior visualization of anatomical structures in the periphery of the sella turcica compared to the microscopic technique. We identified the anatomical location of tumor remnants in iMRI and evaluated risk factors for secondary resection after iMRI and hereby selected patients with pituitary adenomas who may benefit from iMRI-assisted resection.

METHODS

We conducted a retrospective monocenter study of patients who underwent iMRI-assisted transsphenoidal surgical resection of pituitary adenomas at our department between 2012 and 2020. A total number of 190 consecutive iMRI-assisted transsphenoidal surgeries of pituitary adenomas graded as Knosp 0-2 were selected for analysis. Exclusion criteria were missing iMRI availability or pathologies other than adenomas. Of these 190 cases, 46.3% (N = 88) were treated with microscopic, 48.4% (N = 92) with endoscopic, and 5.3% (N = 10) with endoscopic-assisted technique. Volumetric measurement of preoperative, intraoperative, and postoperative tumor extension was performed. Demographic data, tumor characteristics, and MRI features were evaluated. Additionally, analysis of adenoma remnants identified by iMRI was performed.

RESULTS

An additional resection after iMRI was performed in 16.3% (N = 31). iMRI helped to reach gross total resection (GTR) in 83.9% (26/31) of these cases. False-positive resection was found in 1 patient (0.5%). Multivariable logistic analysis identified tumor volume (OR = 1.2, p = 0.007) recurrence (OR = 11.3, p = 0.002) and microscopic technique (OR = 2.8, p = 0.029) as independent risk factors for additional resection. Simultaneously, the endoscopic technique was significantly associated with GTR as evaluated by iMRI (OR = 2.8, p = 0.011) and postoperative MRI (OR = 5.8, p = 0.027). The detailed analysis of adenoma remnants on iMRI revealed the suprasellar location in a diaphragm fold, penetrating tumor above the diaphragm, or undetected invasion of cavernous sinus as well as in case of microscopic resection tumor location outside the line of sight as the main reasons for incomplete resections.

CONCLUSION

Tumor volume, recurrence, and microscopic technique were identified as independent predictors for additional resection in patients with Knosp 0-2 adenomas. iMRI might increase the extent of resection (EOR) safely even after the endoscopic visualization of the sella with very low risk for false-positive findings. Remnants of tumors hidden within the diaphragmic folds, intrathecally, or behind the infiltrated wall of cavernous sinus not recognized on preoperative MRI were the most common findings in iMRI.

Using Histopathology to Assess the Reliability of Intraoperative Magnetic Resonance Imaging in Guiding Additional Brain Tumor Resection: A Multicenter Study

BACKGROUND

Intraoperative magnetic resonance imaging (iMRI) is a powerful tool for guiding brain tumor resections, provided that it accurately discerns residual tumor.

OBJECTIVE

To use histopathology to assess how reliably iMRI may discern additional tumor for a variety of tumor types, independent of the indications for iMRI.

METHODS

A multicenter database was used to calculate the odds of additional resection during the same surgical session for grade I to IV gliomas and pituitary adenomas. The reliability of iMRI for identifying residual tumor was assessed using histopathology of tissue resected after iMRI.

RESULTS

Gliomas (904/1517 cases, 59.6%) were more likely than pituitary adenomas (176/515, 34.2%) to receive additional resection after iMRI (P < .001), but these tumors were equally likely to have additional tissue sent for histopathology (398/904, 44.4% vs 66/176, 37.5%; P = .11). Tissue samples were available for resections after iMRI for 464 cases, with 415 (89.4%) positive for tumor. Additional resections after iMRI for gliomas (361/398, 90.7%) were more likely to yield additional tumor compared to pituitary adenomas (54/66, 81.8%) (P = .03). There were no significant differences in resection after iMRI yielding histopathologically positive tumor between grade I (58/65 cases, 89.2%; referent), grade II (82/92, 89.1%) (P = .98), grade III (72/81, 88.9%) (P = .95), or grade IV gliomas (149/160, 93.1%) (P = .33). Additional resection for previously resected tumors (122/135 cases, 90.4%) was equally likely to yield histopathologically confirmed tumor compared to newly-diagnosed tumors (293/329, 89.0%) (P = .83).

CONCLUSION

Histopathological analysis of tissue resected after use of iMRI for grade I to IV gliomas and pituitary adenomas demonstrates that iMRI is highly reliable for identifying residual tumor.