Large endocervical polyp with cartilaginous and osseous metaplasia: a hitherto unreported entity.

The author reports a previously unrecognized entity of cervical polyp with cartilaginous and osseous metaplasia. A 57-year-old woman (gravida 0, para 0) was admitted to the hospital because of genital bleeding. A colposcopic examination revealed a large endocervical polyp (12 x 13 x 30 mm), and a polypectomy was performed. Microscopically, the polyp was covered by a layer of columnar epithelium. It consisted of the following 4 elements: fibrous tissue with chronic inflammation, young cartilage with chondroblastlike cells, young ossification with focal osteoblastlike and osteoclastlike cells, and collagenous tissue. These elements were intimately admixed and there was a gradual transition among these elements. No epithelial elements were recognized. No atypia or mitotic figures were noted. Immunohistochemically, the tumor cells were positive for vimentin, bone morphogenetic protein-2 and transforming growth factor-beta1, and negative for cytokeratins, epithelial membrane antigen, alpha-smooth muscle antigen, CD34, desmin, S100 protein, neuron-specific enolase, p53 protein, and CD45. Macrophages including the giant cells were positive for CD68. Ki-67 labeling was 0.5%. The pathologic diagnosis was endocervical polyp with cartilaginous and osseous metaplasia.