-Case Reports-

Secondary Cutaneous Ossification in Keloids of the Lower Abdomen: A Report of Two Cases

Mamiko Tosa¹, Shin-ichi Ansai² and Rei Ogawa¹

¹Department of Plastic, Reconstructive and Aesthetic Surgery, Nippon Medical School Hospital, Tokyo, Japan
²Division of Dermatology and Dermatopathology, Nippon Medical School Musashikosugi Hospital, Kanagawa, Japan

Cutaneous ossification is a rare benign dermatological condition in which bone forms in the dermis or subcutaneous tissue. It is classified as primary when it emerges without a pre-existing condition and secondary when it is associated with an underlying condition such as trauma, scars, inflammation, or neoplastic disease. The secondary form accounts for most cases of cutaneous ossification. The pathogenesis of cutaneous ossification is not clear. Keloids are benign fibroproliferative skin disorders characterized by chronic inflammation. Their pathogenesis is also not fully understood. We report two cases of postoperative secondary ossification in lower abdominal keloids and review the literature on secondary ossification of the skin. We speculate that severe chronic inflammation in keloids drives osteoblastic transformation of mesenchymal stem cells, endothelial cells, or fibroblasts in the keloids.

J Nippon Med Sch 2022; 89: 546-549

Keywords
cutaneous ossification, keloid, secondary ossification, inflammation

Correspondence to
Mamiko Tosa, Department of Plastic, Reconstructive and Aesthetic Surgery, Nippon Medical School Hospital, 1-1-5 Sendagi, Bunkyo-ku, Tokyo 113-8603, Japan
tosa-m@nms.ac.jp

Received, March 17, 2021
Accepted, April 30, 2021