We acknowledge with pleasure the contributions of Dr. Nagashima (Tokyo, Japan), Dr. Teraki (Tokyo, Japan), Dr. Miyauchi (Nagai, Japan), PD Dr. Metze (Münster, Germany), Dr. Kimura (Sapporo, Japan), all of whom provided clinical material and sections of tissue from patients, and of Dr. Chongchitnant (Ackerman Academy, New York) who shot the photomicrographs.