PLCD1 and trichilemmal cyst: These findings provide strong evidence that trichilemmal cysts are genetically driven entities arising from a defined somatic-germline interaction in PLCD1, rather than merely sporadic benign lesions Research has demonstrated the existence of studies that provide substantial evidence for the proposition that trichilemmal cysts, which predominantly manifest as sporadic benign lesions, are not merely sporadic benign lesions, but rather genetically determined formations arising from a somatic-germline interaction defined in PLCD1.9