Background/Objectives: There is an increasing need for methods that provide improved insight into the molecular basis of colorectal cancer (CRC) and thus a better understanding of its morphological heterogeneity. The objectives of this study were to evaluate the use of imaging mass spectrometry (IMS) to examine tumor margins and gain insight into the molecular heterogeneity of CRC. Methods: An observational study involving 10 cases was conducted. Native tissue samples were collected during the subject’s surgery, and consecutively taken tissue sections were immediately prepared for light microscopic and IMS analysis. IMS was performed across the 200–1000 Da mass range, divided into four sub-ranges, using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF MS) in both negative and positive modes of ionization. For tumor margin and tissue heterogeneity assessment, image segmentation was used. Segmented MS images were analyzed against the respective light microscopy images of hematoxylin-eosin-stained tissue sections. Results: Quantitative analysis of the sample collection indicated that IMS enabled correct recognition of tumor margin in the 800–1000 Da range using binary segmentation. Denary image segmentation depicted tissue heterogeneity in greater detail. The strongest m/z signals specific to tumor, peritumor, and margins were identified and tentatively annotated: aside from dCTP, all other compounds were patient-specific, indicating interindividual variations in the molecular composition of CRC. Conclusions: IMS provides new insights into the morphological and biochemical properties of CRC: binary segmented MS images can clearly depict the tumor margin in the 800–1000 Da range, while denary segmented MS images depict intra- and inter-individual molecular heterogeneity of CRC.

Intestinal mature B-cell non-Hodgkin lymphoma (B-NHL) is the most common pediatric gastrointestinal lymphoma, but presentation as acute mechanical bowel obstruction remains rare and still challenging. Evidence guiding emergency surgical management in children is limited to small retrospective series and case reports. This case series describes three children with intestinal B-NHL presenting with acute mechanical bowel obstruction, or intussusception. All three patients presented to the emergency department with signs of bowel obstruction and an acute abdomen, and in one patient initial diagnosis suggested appendicitis. Imaging revealed either intussusception with a lead mass or large obstructing abdominal tumors. Surgery within 8–48 h consisted of segmental bowel resection with primary anastomosis in all cases. The final diagnoses were Burkitt lymphoma in two patients and diffuse large B-cell lymphoma (DLBCL) in one. The wider literature confirms that lymphoma-related intussusception and obstructing ileal masses occur predominantly in older children, are frequently misdiagnosed preoperatively, and often require emergency surgery both for diagnosis and for treatment of obstruction. Available literature has examined outcomes after emergency surgery for intestinal lymphoma, but the present case series cannot determine its independent effect on long-term oncologic prognosis. Pediatric intestinal B-NHL can present as acute mechanical bowel obstruction or intussusception suggesting common surgical conditions. Surgeons play a crucial role in early recognition, appropriate extent of resection, and timely transition to oncologic care. Further multicenter studies are needed to optimize surgical decision-making and quantify outcomes in this rare but life-threatening presentation.