Ganglion Cysts Are NOT Part of Carney Complex
Ganglion cysts are not a recognized feature of Carney complex. The established diagnostic criteria for Carney complex include specific cutaneous manifestations (spotty lentigines, blue nevi, cutaneous/mucosal myxomas), cardiac myxomas, endocrine tumors, and other specific features, but ganglion cysts are conspicuously absent from these criteria 1, 2.
Established Carney Complex Features
The American College of Medical Genetics and Genomics guidelines clearly define the diagnostic criteria for Carney complex, which include 1:
- Cutaneous findings: Spotty brown-to-black lentigines on lips, conjunctiva, canthi, and genital mucosa; multiple blue nevi (including epithelioid blue nevus); cutaneous and mucosal myxomas 2
- Cardiac manifestations: Cardiac myxomas 1
- Bone lesions: Osteochondromyxomas 1
- Endocrine tumors: Primary pigmented nodular adrenocortical disease, growth hormone-producing pituitary adenomas, thyroid tumors 1
- Breast lesions: Myxomatosis and multiple ductal adenomas 1
Why Ganglion Cysts Are Not Included
Ganglion cysts are common benign soft-tissue tumors that arise from joints or tendon sheaths, accounting for 50-70% of all hand and wrist masses, and are not associated with any hereditary cancer predisposition syndrome 3. They are mucinous or gelatinous-filled pseudocysts lined by dense fibro-connective tissue, not true neoplasms 4, 5.
The pathophysiology of ganglion cysts involves trauma and joint tissue defects, not the genetic mutations (PRKAR1A) that characterize Carney complex 4. These are sporadic lesions that occur in the general population without syndromic associations 6, 3.
Clinical Distinction
When evaluating a patient for Carney complex, systematically assess for 2:
- Mucosal pigmentation patterns: Lentigines characteristically involve mucosal surfaces (lips, conjunctiva, genital mucosa), not simple freckles 2
- Multiple blue nevi: Anywhere on the body, including the epithelioid blue nevus subtype 2
- Myxomas: Soft tissue tumors on skin and mucous membranes (NOT ganglion cysts) 2
- Endocrine features: Cushingoid appearance or acromegalic features 2
Critical Pitfall to Avoid
Do not confuse cutaneous/mucosal myxomas (which ARE part of Carney complex) with ganglion cysts (which are NOT). Myxomas are true soft tissue tumors with myxoid degeneration, while ganglion cysts are pseudocysts arising from joint capsules or tendon sheaths 4, 5. The histopathology, location patterns, and clinical significance are entirely different.
Genetic referral for Carney complex should occur when spotty skin pigmentation, cutaneous/mucosal myxoma, or epithelioid blue nevus is present PLUS one additional Carney complex criterion—ganglion cysts do not qualify as a criterion 1, 2.