training program sln micrometastasis vs itc roderick r. turner, md adjunct member, jwci
TRANSCRIPT
Training Program SLN Micrometastasis vs ITC
Roderick R. Turner, MD
Adjunct Member, JWCI
Introduction
• ITC and micrometastasis are distinguished on the basis of the greatest dimension of the largest cluster of tumor cells.
• Each cluster or single cell is measured separately.• The number of clusters or single cells does not change
categorization; but, in clinical practice, an explanatory comment may be added to a report.
• Infrequently, small volume axillary disease may be seen only in perinodal soft tissue or afferent lymphatics; this is regarded as nodal metastasis and classified, as above, by cluster size.
Definitions - Cluster
• A cluster is a confluent focus of tumor cells touching other tumor cells. This is determined from the two-dimensional image of the microscopic section.
• Clusters or cells separated by a single benign cell or a spatial gap are measured as separate clusters, except when fibroblastic reaction to the tumor cells has caused the separation.
Definitions - Measurements
• Measurements are determined by the greatest dimension of the largest tumor cell cluster. Single cells are measured separately. A known field diameter (or ocular micrometer) should be utilized for consistent and reliable categorization.
• Measurements are made solely from the two-dimensional plane(s) of section(s) examined, H-E or IHC. In clinical practice, deeper sections and IHC are available options for further evaluation.
• Do not use the distance that separate clusters span, sum measurements of multiple clusters, or count/estimate tumor cell numbers.
Definitions – Isolated Tumor Cells
• Small cluster(s), largest cluster not greater than 0.20mm.• Single cells, as in the dispersed lobular pattern, represent ITC;
densely crowded cells when contiguous/touching are measured and classified by the largest group of contiguous/touching cells.
• A single cell may qualify as ITC, but only when cytologic and microanatomic features are supportive of a carcinoma cell. This may include a strongly positive immunoreaction. Cellular debris and contaminants are excluded.
• Mitotic activity (proliferation) is not considered.• Microanatomic location is not a factor in classification; ITC may be
found in nodal parenchyma, capsular or subcapsular spaces, or extranodal/afferent lymphatic vessels.
Definitions - Micrometastasis
• Largest cluster or confluent focus is greater than 0.20mm, but no greater than 2.0mm.
• Usually seen in nodal parenchyma; but,when found in perinodal tissue, it is classified as for nodal disease based on size of deposit.
• For borderline or indeterminate findings, at the two ends of this spectrum, select the lower N classification.
0.2 mm
TC #1 (1 of 2) Mostly ITC clusters, micrometastasis on right. See next.
0.2 mm
TC#1 (2 of 2) Small contiguous micrometastasis, 0.25mm
2.0 mm
TC#2 (1 of 2) Clusters are separated by fibroblastic reaction; this is a small macrometastasis, 3.0mm. See next for better detail.
0.2 mm
TC#2 (2 of 2) The clusters are separated by fibroblastic reaction; largest dimension seen on previous slide (macrometastasis) is appropriate
TC#3 Small micrometastasis, 0.35mm, and other ITC clusters
0.2 mm2.0 mm
TC#4 (1 of 2) Lobular carcinoma, mostly single ITC. Upper right shows dense crowding. See next.
0.2 mm
TC#4 (2 of 2) Contiguous grouping of touching tumor cells measures 0.22mm and qualifies as micrometastasis
0.2 mm
TC#5 Small micrometastasis, 0.22mm, and ITC clusters
0.2 mm
TC#6 (1 of 2). Few clusters of ITC in nodal parenchyma. See next.
0.2 mm
TC#6 (2 of 2). Multiple ITC clusters in nodal parenchyma, largest 0.20mm.
0.2 mm
TC#7. Multiple tiny clusters and a poorly cohesive, but contiguous, one at upper left. Small micrometastasis, 0.23mm.
, TC#8 (1 of 2) Tumor cell clusters in perinodal soft tissue/capsule with fibroblastic reaction. Micrometastasis 1.5mm. See next.
TC#8 (2 of 2). Closer view of fibrotic reaction between clusters.
0.2 mm
TC#9 (1 of 2) Tubular pattern. Multiple clusters of ITC.
0.1 mm
TC#9 (2 of 2). Largest ITC cluster 0.16mm
0.1 mm
TC#10. Single cell, strongly CK-IHC (+), 3x diameter of lymphocytes. Minimally qualifies as ITC
TC#11. ITC, 3 cells, in parenchyma.
TC#12. Many ITC clusters and single cells.
0.1 mm
TC#13. Several clusters of ITC, largest approx 0.09mm.
TC#14. Multiple clusters of ITC in subcapsular sinus.
END