Osseous Metaplasia of the Cervix: A Rare Transformation Can Mimic a Tumor-Literature Review

A Rare Case of Osseous Metaplasia in Canine Leiomyoma and Plasticity of Smooth Muscle Cell

Metaplasia is a transformation of one mature cell type to other kinds of mature cells. Metaplasia is hardly detected in benign tumors, whereas it is frequently observed in malignant tumors. In this study, we report the first case of osseous metaplasia in canine leiomyoma. The region of osseous metaplasia was highly eosinophilic and had various sizes of distinct lacunae. The osseoid material was confirmed by Von Kossa staining. Except for the osseous metaplasia, the mass presented typical features of leiomyoma without any histopathological features of malignancy. The characteristics of malignant tumors, including pleomorphism, mitotic figures, and lymphatic metastasis were not identified and the mass was proven to be a benign tumor. The osseous metaplasia in leiomyoma without dysplastic changes might be due to plasticity which is a unique feature of smooth muscle cells, whether the tumor is malignant or not. This case suggests the possible occurrence of osseous metaplasia in leiomyoma, which has been overlooked due to the lack of reports. Also, it is recommended to pay attention to making a diagnosis of smooth muscle tumor with metaplasia so as not to be confused with leiomyosarcoma and leiomyoma variants.

Osseous metaplasia of the endometrium: A multicenter retrospective study

OBJECTIVE

To describe clinical and demographic characteristics, ultrasound appearance, and hysteroscopic outcomes of patients with endometrial osseous metaplasia.

STUDY DESIGN

We conducted a multicenter retrospective study. We retrospectively reviewed the medical records of all consecutive patients who were referred for hysteroscopy at fourteen institutions in Venezuela, Spain, Morocco, India, Ukraine, Argentina, the United States, and Italy between 1994 and 2018. We identified and included all patients who had a diagnosis of osseous metaplasia at the pathologic report, and data were retrieved from the medical records.

RESULTS

Between January 1st, 1994, and December 31st, 2018, 63 patients out of a total of 419,673 women who underwent hysteroscopy had a diagnosis of osseous metaplasia (0.015%). Most patients were 31-40 years old (53.7%), were Caucasian or Hispanic (95.5%), and had at least one previous pregnancy (86.9%). Forty-one out of 63 patients (65.1%) had at least one miscarriage before the index hysteroscopy. Dysmenorrhea, abnormal uterine bleeding, and infertility were reported by 34.9%, 27.0%, and 23.8% of patients. 14.3% of women were asymptomatic. Preoperative transvaginal ultrasound was available and identified a hyperechoic area of variable size with posterior acoustic shadowing in all cases. Hysteroscopy was successful without complications in all 63 cases. Follow-up data were available in 30.2% of patients: 69.2% of patients were infertile, and 44.4% of them conceived and achieved a live birth; all other symptoms improved after hysteroscopic treatment in all patients.

CONCLUSIONS

Osseous metaplasia appears associated with multiple unspecific gynecologic symptoms without the predominant role of infertility, as previously suggested. Although endometrial osseous metaplasia is rare, gynecologists should consider this pathologic condition when the characteristic ultrasound appearance is detected, being hysteroscopic treatment effective.