Porocarcinoma is a malignancy of the eccrine sweat gland. It may arise de novo or develop from pre-existing poroma and hidroacanthoma simplex. A 56-year-old woman was presented with a pinkish plaque on her left posterior thigh. She was diagnosed with hidroacanthoma simplex 6 years ago, and the same lesion had changed in size and shape. Histopathology revealed intraepidermal proliferation of small-sized basaloid cells, continuing to the proliferation of large polygonal tumor cells. This malignant transformation was consistent with the change in p53 expression pattern. The patient underwent wide excision with clear resection margin, and no evidence of recurrence was noted. We highlight this case in that the transition from hidroacanthoma simplex to porocarcinoma in situ was confirmed in the same tissue, as demonstrated by immunohistochemical staining.

BACKGROUND: The repair of large bone defects remains a significant challenge in clinical practice and requires bone grafts or substitute materials. In this study, we developed a unique hybrid bone scaffold comprising a three dimensional (3D)-printed metal plate for weight bearing and a biodegradable polymer tube serving as bone conduit. We assessed the long-term effect of the hybrid bone scaffold in repairing radial bone defects in a beagle model. METHODS: Bone defects were created surgically on the radial bone of three beagle dogs and individually-tailored scaffolds were used for reconstruction with or without injection of autologous bone and decellularized extracellular matrix (dECM). The repaired tissue was evaluated by X-ray, micro-computed tomography, and histological observation 6 months after surgery. The functional integrity of hybrid bone scaffold-mediated reconstructions was assessed by gait analysis. RESULTS: In vivo analysis showed that the hybrid bone scaffolds maintained the physical space and bone conductivity around the defect. New bone was formed adjacent to the scaffolds. Addition of autologous bone and dECM in the polymer tube improved healing by enhancing bone induction and osteoconduction. Furthermore, the beagles’ gait appeared normal by 4 months. CONCLUSION The future of bone healing and regeneration is closely related to advances in tissue engineering. Bone production using autologous bone and dECM loaded on 3D-printed hybrid bone scaffolds can successfully induce osteogenesis and provide mechanical force for functional bone regeneration, even in large bone defects.