A study of familial male breast carcinoma and a second report.

We report on a second instance of familial male breast carcinoma in which the relationship is between father and son. Both patients show a similar histologic type, papillary adenocarcinoma, which is rarely found in male breast cancer. Hormonal and chromosomal studies in the index case (son) did not suggest any predisposing factors and were not available at the time of the father's diagnosis. Other than the familial relationship (and histologic similarity) we could discover no other correlation. This may indicate a coincidental occurrence or hidden factors that are unrecognized or not able to be analyzed at this time.