Abstract
Lynch syndrome II is characterized by an autosomal dominantly inherited susceptibility to early onset colon cancer with proximal predominance, an excess of synchronous and metachronous colonic cancer, carcinoma of the endometrium, ovary, and multiple primary cancer excess. Knowledge of the full tumor spectrum in this disorder(s) remains elusive. Cancers that are uncommon in this disease, but present in three extended Lynch syndrome II families, included brain tumors, carcinoma of the bile duct, duodenum, the urological system, and breasts. Long-term followup of these families (as long as two decades) provided the opportunity to trace in depth this tumor spectrum. Full scrutiny of cancer of all anatomic sites in the absence of biomarkers of high sensitivity and specificity to the cancer-prone genotype will be necessary to comprehend more clearly whether these (or other) cancer sites are integral to this disorder, whether common environmental exposures are involved and, finally, whether chance can explain these cancer associations.