Table 1. . Diagnostic criteria for Cowden syndrome^†.

Major criteria	Minor criteria
• Breast cancer • Endometrial cancer (epithelial) • Thyroid cancer (follicular) • GI hamartomas • Lhermitte–Duclos disease (adult) • Macrocephaly (≥97 percentile: 58 cm for females, 60 cm for males) • Macular pigmentation of glans penis • Multiple mucocutaneous lesions (any of the following):   ○ ≥3 multiple trichilemmomas   ○ ≥3 acral keratoses   ○ ≥3 mucocutaneous neuromas • ≥3 oral papillomas	Autism spectrum disorder • Colon cancer • ≥3 esophageal glycogenic acanthosis • ≥3 lipomas • Mental retardation (i.e., IQ ≤75) • Renal cell carcinoma • Testicular lipomatosis • Thyroid cancer (papillary or follicular variant of papillary) • Thyroid structural lesions (e.g., adenoma, multinodular goiter) • Vascular anomalies (including multiple intracranial developmental venous anomalies)

^†Three or more major criteria, including macrocephaly, Lhermitte–Duclos disease or GI hamartomas; or two major and three or more minor criteria are needed for a diagnosis of Cowden syndrome.

GI: Gastrointestinal; IQ: Intelligence quotient.

Adapted with permission from [12].