| • | usually firm or stony hard, skin colored nodules or purple plums |
| • | unusual for mets to be on extremities |
| • | periumbilical (Sister Mary Joseph’s) nodule heralds underlying gastric CA |
in general:
| • | histology often less differentiated than primary |
| • | adenocarcinoma metastatic to skin à most often colon, lung, breast |
| • | squamous cell metastatic to skin à most often oral cavity, lung, esophagus |
| • | undifferentiated à lung or breast |
| • | tumors that invade veins: (e.g. lung, kidney) can metastasize to diverse sites distant from primary |
| • | tumors that invade lymphatics: (e.g. breast, SCC of oral cavity) appear late, and often involve skin overlying primary tumor |
METS TO THE SCALP:
| • | characteristically breast CA in females; lung CA in males; and kidney |
see also carcinoma erysipeloides
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