Handling & Grossing of Colo-rectal Specimens for Tumours for Medical Officers in Pathology Dr Gayana Mahendra Department of Pathology Faculty of Medicine University of Kelaniya
Your Role in handling colorectal specimens Assist the reporting pathologist in providing essential information An accurate and detailed macroscopic description is an essential part of a quality report Prognostic information Tumour size Distance to margins Serosal involvement Perforations Lymph node harvest Reorientation and relook is not possible after a good cut up!!
Your Role Missing the lesions, missing the lymph nodes, inaccurate measurements Problem for the reporting Pathologist/inaccurate report Misinterpreted by the Clinician Improper treatment to the patient
How could you perform an optimum job? Know the gross anatomy of the region well Be familiar with surgical procedures done in the region Always adhere to the general guidelines in surgical pathology Cross checking the samples and requests, specimen numbering etc Know the clinical details indication for the surgery, neo-adjuvant therapy, previous histology, IBD, polyposis syndromes etc Allow proper fixation Use the principles appropriately in each of the samples
Gross anatomy of the colorectal region
Peritoneal reflection at rectum Peritoneum descends over the anterior surface of the lower sigmoid colon and upper rectum. Then curves (reflects) back upwards to cover the top of either the bladder in male or the uterus in female. This curve is known as the anterior peritoneal reflection. Beneath it the entire rectum is enclosed by the mesorectum and thus possesses a continuous circumferential margin
Peritoneal covering of the colo-rectum Transverse & sigmoid colon Intraperitoneal Complete serosal covering & a mesentery Ascending & descending colon Retroperitoneal No serosa posteriorly/laterally & lack a true mesentery Upper rectum Above peritoneal reflection Lower rectum Infraperitoneal No serosa Serosa anteriorly and laterally only
Extent of peritoneal covering Radial Margin Circumferential Margin
Blood supply
Layers of the bowel
Spread of bowel cancer
A-B A-C B-C C-E D-E D-F D-G D-H A-D A-E A-H Right hemicolectomy Extended Right hemicolectomy Transvese colectomy left hemicolectomy Sigmoid colectomy Anterior resection ultra low anterior resection Abdomino perineal resection Subtotal colectomy Total colectomy Total proctocolectomy
Preparation of the specimen Proper fixing -24-48hrs Opening the specimen soon after receipt helps formalin to reach the mucosa Remove faecal material by careful washing Cut along the bowel in ante-mesenteric border staring from the proximal end just before (1-2cm) the proximal end of the tumour Open the distal part similarly up to the tumour Pass a formalin soaked wick through the lumen into the tumour for better fixation Do not open the tumour Fixation is facilitated by pinning onto a cork board.
Large bowel resection after fixation.
Specimen Description Type of specimen/surgery Orient the specimen Relation to anatomy Relation to sutures at margins- sigmoid & transverse colectomy specimens Length of bowel Entire length Separate anatomical subareas where possible- ileum, appendix Mesocolon in 3 dimension Diameters of proximal and distal resection margins Serosal involvement/ perforations
Description of tumour Open the tumour transversely 3-4mm thin slices Location of the tumour Decide by the bulk of the tumour Maximum diameter of the tumour Examine the slices to see the level of maximum invasion Take photographs for references, macro-micro correlations MDT etc Distance to the closest longitudinal resection margin Perforation through the tumour into the bowel wall
Different morphologies of tumours
Describing the different morphologies of tumours Growth- polypoidal growth, ulcerating growth, circumferential growth Polyp Ulcer circumferential thickening, napkin ring lesion, stenosing lesion If there are two or more lesions treat as separate tumours and describe/ sample separately Observe and describe any other associated lesions- [polyps.
Describing the different morphologies of tumours Growth- polypoidal growth, ulcerating growth, circumferential growth Polyp Ulcer circumferential thickening, napkin ring lesion, stenosing lesion If there are two or more lesions treat as separate tumours and describe/ sample separately Observe and describe any other associated lesions- [polyps, ulcers, IBD etc]
Description of tumour in AR specimens Beneath the anterior peritoneal reflection the entire rectum is enclosed by the mesorectum and thus possesses a continuous circumferential margin Mesorectum comes to an apex on the posterior aspect of the rectum Describe the tumour in relation to the anterior peritoneal reflection Above- at- below Measure distance of anterior peritoneal reflection to the distal resection margin
AR anterior view AR posterior view APEX
Plane of mesorectal excision Desired aim at surgery is to excise the entire mesorectum Relatively smooth, uniform mesorectum- mesorectal plane of excision /TME Irregular mesorectal margin - intramesorectal plane of excision Opened muscular wall of the rectum intramuscular plane of excision
Colouring the CRM in AR and APR Colour the CRM, preferably different colours on left ad right sides Transversely slice the bowel and the perirectal fat up to the CRM Examine the transversely sliced sections to identify maximum depth of invasion macroscopic vascular invasion The measurement of the distance of extramural tumour spread The distance of tumour to the CRM.
Block Selection At least four blocks of the tumour to show: the deepest tumour penetration into or through the bowel wall involvement of the serosal surface invasion of veins involvement of any adjacent organs A block to show the closest distance of tumour (main tumour, extramural deposit or Ln whichever the closest) to the CRM PRM and DRM Closest longitudinal margin to identify the distance from the tumour A block of tumour and adjacent mucosa Any synchronous pathology identified- polyps, abnormal mucosa etc A block of normal-appearing bowel including ileum/appendix
Block Selection Blue : tumour Dark green : longitudinal margins Light green : distance to longitudinal margins Orange : radial margin Orange-yellow : distance to the radial margin
Identifying and sampling of lymph nodes Highest / apical/ high-tie LN The first node identified by sectioning serially and distally from the sutured vascular margin Identified and blocked separately All of the mesentery between the tumour and the highest LN is serially sliced to identify nodes LNs that are situated very close to the CRM should be blocked with the inked margin
How many nodes to be sampled? All the nodes that can be found in a specimen are examined Yield of nodes will depend on Diligence Skill Nodal yield is low in Neoadjuvant therapy Obese and elderly patients
A sample macroscopy A segment of large bowel including the sigmoid colon and rectum measuring 190mm in length. The distal resection margin (DRM) is 50 mm and the proximal resection margin (PRM) is 12 mm in diameters. The peritoneal reflection is seen at 30mm from the DRM anteriorly and 160 mm posteriorly. The mesorectal excision is complete. On opening the bowel, there is a circumferential growth, mostly involving the posterior rectum, partially obstructing the lumen measuring 30x25x15mm. This is situated at and above the peritoneal reflection and is seen 30mm proximal to the DRM. The lesion extends to the circumferential resection margin (CRM) macroscopically. The apical lymph node measures 13mm and 18 lymph nodes varying in size from 8-10mm were identified in the perirectal fat, some of which are very close to the CRM. Rest of the rectal mucosa and the sigmoid colon appear unremarkable
Reference https://www.rcpath.org/profession/publications/cancerdatasets.html Download this presentation at http://medicine.kln.ac.lk/depts/pathology/discussions-inhistopathology.html