Abstract
Hereditary nonpolyposis colorectal cancer (HNPCC) accounts for about 4% to 6% of the total colorectal cancer burden. It is subdivided into Lynch syndrome I and II. Lynch syndrome I is characterized by an autosomal dominant inheritance pattern for site-specific, early onset, adenocarcinoma of the colon, with proximal predominance and an excess of synchronous and metachronous colonic cancers. Lynch syndrome II (cancer family syndrome) shows these same colon cancer characteristics, but differs in that there is an excess proclivity of other forms of cancer, particularly of the endometrium and ovary. This article documents a family that shows features of Lynch syndrome II. Unique aspects pertain to a patient who is in the direct genetic lineage (whose five brothers manifested colonic cancer), but who developed carcinoma of the uterine cervix at age 34 and laryngeal cancer at 60. The pedigree also shows uterine cervical carcinoma among other patients at genetic risk. Her son, who is a nonsmoker and nondrinker, manifested laryngeal cancet at age 31. These observations appear to add new information about tumor heterogeneity in HNPCC.