Recurrent melanoma development in a Caucasian female with CDKN2A+ mutation and FAMMM syndrome: A case report

Melanoma is a form of skin cancer originating from melanocytes that has an increasing incidence over the past few decades. From 1992 to 2010, the overall incidence of melanoma was 12.29 cases per 100,000 person-years in Canada. Approximately 10% of cases are attributed to a hereditary component, with one of the most common being familial atypical multiple mole melanoma syndrome. In this case report, we highlight the atypical case of a middle-aged Caucasian female with familial atypical multiple mole melanoma syndrome, who has developed dozens of primary melanomas over the past decade. We highlight the management of her case, as well as the importance of monitoring by multiple other subspecialists given the propensity for the development of alternate malignancies.

CDKN2A founder mutation in pancreatic ductal adenocarcinoma patients without cutaneous features of Familial Atypical Multiple Mole Melanoma (FAMMM) syndrome

Background

Approximately 5% to 10% of pancreatic ductal adenocarcinoma (PDAC) has a hereditary basis. In most of these defined hereditary cancer syndromes, PDAC is not the predominant cancer type. Traditional criteria for publicly funded genetic testing typically require the presence of a set combination of the predominant syndrome-associated cancer types in the family history.

We report the identification of a CDKN2A pathogenic variant in a PDAC-prone family without the cutaneous features of multiple moles or melanoma that are characteristic of the Familial Atypical Multiple Mole Melanoma (FAMMM) Syndrome identified in a universal testing algorithm for inherited mutations in pancreatic cancer patients.

Case presentation

We present the case of two brothers of English ancestry diagnosed with PDAC within the same 12 month period, at the respective ages of 63 and 64 years of age. Neither brother reported a personal history of multiple moles or melanoma. Family history was positive for two second-degree relatives diagnosed with PDAC but was negative for other cancers or multiple moles in first- and second-degree relatives. Due to the absence of melanoma, this family did not meet provincial criteria for publicly funded genetic testing. Clinical genetic testing offered through a research grant identified a pathogenic variant in the CDKN2A gene c.377 T > A (p.Val126Asp). This variant is a North American founder mutation believed to pre-date colonization.

Conclusions

This case reminds clinicians to consider the possibility of a germline CDKN2A mutation in families with a high prevalence of PDAC, even in the absence of moles or melanoma. This case supports recent guidelines published by the American College of Medical Genetics and Genomics (ACMG) that genetics referrals are indicated in families with three or more cases of PDAC regardless of other cancer types in the family. A multi-gene panel approach is of particular benefit in diagnosing inherited cancer susceptibility in PDAC-only families.

Familial atypical multiple mole melanoma (FAMMM) syndrome: history, genetics, and heterogeneity

Approximately 5-10 % of cutaneous melanoma occurs in kindreds with a hereditary predisposition. Mutations in the CDKN2A gene are found to occur in approximately 20-40 % of these kindreds. The first historical mention of what is now called the familial atypical multiple mole melanoma syndrome appears to be from 1820, with more reports throughout the 1950s, 1960s, and later years. In 1991, Lynch and Fusaro described an association between familial multiple mole melanoma and pancreatic cancer and work continues to elucidate the syndrome's genotypic and phenotypic heterogeneity. Individuals at risk for familial melanoma need periodic screenings. Unfortunately, adequate screening for pancreatic cancer does not currently exist, but pancreatic cancer's prominence in the hereditary setting will hopefully act as a stimulus for development of novel screening measures.