Figure 4

Continuity between interstitium and draining lymphatics. (A–C) Colon tissue with submucosal tattoo. (A) Black pigment endoscopically injected into submucosa of colonic wall before resection of colonic malignancy (H&E, 10×). (B) Black pigment is present in macrophages in the spaces between collagen bundles (H&E, 40×). (C) Pigment-containing macrophages are present in mesenteric lymph nodes draining the tattooed colon, showing that the interstitial space functionally communicates with lymphatic drainage of the colon (H&E, 20×). Typical images from 4 independent samples evaluated. (D–F) Stage T2 gastric carcinoma, poorly differentiated. (D) Gastric carcinoma present at the mucosal surface (arrows) invades into the submucosa (arrow heads); deeper invasion and lymphovascular invasion were not seen (H&E, 4×). (E) Poorly differentiated tumor cells infiltrate, singly and in very small clusters, through the interstitial space of the gastric submucosa, isolating pre-existing collagen bundles (H&E, 40×). (F) Metastatic carcinoma in draining mesenteric lymph nodes of the gastric resection specimen; no other metastases were identified clinically or histologically (H&E, 20×). (G–I) Stage T2 malignant melanoma of the skin of the left arm. (G) Malignant melanoma (dark blue) invading into the dermis; lymphovascular invasion not identified (H&E, 4×). (H) Malignant melanoma cells infiltrate, singly and in very small clusters, through the interstitial space of the dermis, isolating pre-existing collagen bundles (H&E, 40×). (I) Metastatic malignant melanoma in draining axillary lymph nodes; no other metastases were identified clinically or histologically (H&E, 10×).