PTEN Hamartoma Tumor Syndrome

Review
In: GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993.
[updated ].

Excerpt

Clinical characteristics: The PTEN hamartoma tumor syndrome (PHTS) includes Cowden syndrome (CS), Bannayan-Riley-Ruvalcaba syndrome (BRRS), PTEN-related Proteus syndrome (PS), and PTEN-related Proteus-like syndrome.

  1. CS is a multiple hamartoma syndrome with a high risk for benign and malignant tumors of the thyroid, breast, kidney, and endometrium. Affected individuals usually have macrocephaly, trichilemmomas, and papillomatous papules, and present by the late 20s. The lifetime risk of developing breast cancer is 85%, with an average age of diagnosis between 38 and 46 years. The lifetime risk for thyroid cancer (usually follicular, rarely papillary, but never medullary thyroid cancer) is approximately 35%. The lifetime risk for renal cell cancer (predominantly of papillary histology) is 34%. The risk for endometrial cancer may approach 28%.

  2. BRRS is a congenital disorder characterized by macrocephaly, intestinal hamartomatous polyposis, lipomas, and pigmented macules of the glans penis.

  3. PS is a complex, highly variable disorder involving congenital malformations and hamartomatous overgrowth of multiple tissues, as well as connective tissue nevi, epidermal nevi, and hyperostoses.

  4. Proteus-like syndrome is undefined but refers to individuals with significant clinical features of PS who do not meet the diagnostic criteria for PS.

Diagnosis/testing: The diagnosis of PHTS is established in a proband by identification of a heterozygous germline PTEN pathogenic variant on molecular genetic testing.

Management: Treatment of manifestations: Treatment for the benign and malignant manifestations of PHTS is the same as for their sporadic counterparts. Topical agents (e.g., 5-fluorouracil), curettage, cryosurgery, or laser ablation may alleviate the mucocutaneous manifestations of CS but are rarely utilized; cutaneous lesions should be excised only if malignancy is suspected or symptoms (e.g., pain, deformity, increased scarring) are significant.

Surveillance: To detect tumors at the earliest, most treatable stages:

  1. Children (age <18 years). Yearly thyroid ultrasound from the time of diagnosis (earliest reported at age 7 years) and skin check with physical examination

  2. Adults. Yearly thyroid ultrasound and dermatologic evaluation

  3. Women beginning at age 30 years. Monthly breast self-examination; annual breast screening (at minimum mammogram; MRI may also be incorporated). Starting by age 35 years, consider transvaginal ultrasound or endometrial biopsy.

  4. Men and women. Colonoscopy beginning at age 35 years with frequency dependent on degree of polyposis identified or family history of early-onset colon cancer (before age 40); biennial (every 2 years) renal imaging (CT or MRI preferred) beginning at age 40 years

  5. Those with a family history of a particular cancer type at an early age. Consider initiating screening 5 to 10 years prior to the youngest age of diagnosis in the family.

Evaluation of relatives at risk: When a PTEN pathogenic variant has been identified in a proband, molecular genetic testing of asymptomatic at-risk relatives can identify those who have the family-specific pathogenic variant and warrant ongoing surveillance.

Genetic counseling: PHTS is inherited in an autosomal dominant manner. Because CS is likely underdiagnosed, the actual proportion of simplex cases (defined as individuals with no obvious family history) and familial cases (defined as ≥2 related affected individuals) cannot be determined. The majority of CS cases are simplex. Perhaps 10%-50% of individuals with CS have an affected parent. Each child of an affected individual has a 50% chance of inheriting the pathogenic variant and developing PHTS. Once a PTEN pathogenic variant has been identified in an affected family member, prenatal testing for a pregnancy at increased risk is possible.

Publication types

  • Review