Follicular cyst in a patient with myotonic dystrophy: a case of cyst with differentiation toward follicular infundibulum, isthmus, inner root sheath, and hair.

We report a case of follicular cyst, which developed in a patient with myotonic dystrophy (MyD). Histopathologically, the cyst showed infundibular and trichilemmal keratinization, inner root sheath differentiation, aggregation of basaloid cells, and pilomatricoma-like changes in the pericystic connective tissue. These findings have been reported in follicular cysts with Gardner's syndrome (GS).