What the Surgeon is Requesting from the Histopathologist
The surgeon wants the pathologist to identify and characterize any intraluminal mass or lesion that served as the "lead point" causing the ileo-ileal intussusception, including its histologic type (benign vs. malignant), size, margins, and degree of invasion.
Understanding the Clinical Context
In adult intussusception, 86-93% of cases have an identifiable pathological lead point (such as a tumor, polyp, inflammatory lesion, or other structural abnormality) that acts as the anchor for the telescoping bowel segment. 1, 2 This contrasts sharply with pediatric intussusception, which is typically idiopathic. 3
The surgeon's question reflects the critical need to determine:
- Whether a lead point exists in the resected specimen
- What type of pathology is present (benign vs. malignant)
- Whether complete excision was achieved
Specific Pathologic Information Required
Primary Diagnostic Question
The pathologist must report whether any intraluminal growth or mass is present within the resected bowel segment that could have initiated the intussusception. 4, 5
Essential Histopathologic Details
When a lead point lesion is identified, the pathology report should include:
Histologic Classification:
- Benign lesions: lipoma, angiolipoma, inflammatory polyps, Meckel's diverticulum, duplication cysts 5, 3, 6, 7
- Malignant lesions: adenocarcinoma, leiomyosarcoma, metastatic tumors, lymphoma 4, 3
Tumor Characteristics (if malignant):
- Histologic subtype according to WHO classification 8
- Grade of differentiation (well, moderately, poorly differentiated, or undifferentiated) 8
- Size of the invasive component and greatest tumor extent 8
- Depth of invasion measured by optical micrometer, particularly depth of submucosal invasion 8
Margin Assessment:
- Distance from resection margins (both vertical/deep and lateral margins) reported in millimeters 8
- Margin status: positive, negative, or close 8
Prognostic Features:
- Lymphovascular invasion: presence or absence 8
- Tumor budding: if observed, should be quantified in hotspot areas 8
- Perineural invasion: if present 8
Clinical Implications of the Pathology Report
If Benign Lead Point Identified
The surgeon can be reassured that limited resection was appropriate and no further oncologic intervention is needed. 3 Common benign causes include lipomas (which can be quite large, as in one reported case measuring 38 × 43 × 61 mm) and angiolipomas. 5, 6
If Malignant Lead Point Identified
The pathology findings determine whether:
- Adequate oncologic resection was performed (based on margin status and lymphovascular invasion) 8
- Additional surgery is required if margins are positive or high-risk features are present 8
- Adjuvant therapy should be considered based on tumor grade, stage, and prognostic features 8
If No Lead Point Identified
This represents the 8-20% of adult intussusceptions that are idiopathic, though this is less common in adults than children. 3 The pathologist should still examine for subtle inflammatory changes, adhesions, or other structural abnormalities that might have contributed.
Critical Pitfall to Avoid
Do not assume all adult intussusceptions are benign. In adults, malignancy is the cause in up to 50% of cases, particularly in colonic intussusception. 6 This is why the surgeon needs detailed pathologic characterization rather than simply confirming intussusception—the management pathway diverges dramatically based on whether the lead point is benign or malignant. 1, 3
The pathology report should follow College of American Pathologists structured templates when malignancy is identified, ensuring all prognostic factors are systematically documented. 8