Parasitic leiomyomas: a systematic review

Abstract

Background

Parasitic leiomyomas were first described as early as 1909 but are a rare condition. In recent years, due to the rise of laparoscopic surgery and power morcellation, several cases of parasitic leiomyomas associated with this surgical procedure have been reported.

Methods

A literature search was performed using PubMed, Embase and Google Scholar with the following combination of keywords: leiomyoma OR uterine neoplasms OR uterine myomectomy OR laparoscopy OR hysterectomy OR peritoneal neoplasms AND parasitic. Papers describing parasitic leiomyomas were included. The results of these studies are summarized herein.

Results

We retrieved abstracts of 756 papers. Of these, 591 were excluded for not fulfilling the inclusion criteria and 54 were removed as duplicates; after full-text assessment, 8 were rejected for presenting cases of malignancy and finally 103 were included in our systematic review. From these, we present information about 274 patients with parasitic leiomyomas. The mean age of women was 40 years (range 18–79 years); and 154 (56%) had no history of uterine surgery, the others (120, 44%) having had a previous myomectomy or hysterectomy. Of the total, 106 (39%) women had a history of power morcellation. The most frequent clinical symptom was abdominal pain (49%) and the most frequent presentation was disseminated peritoneal leiomyomatosis.

Conclusions

While parasitic leiomyoma was first described a century ago, the recent introduction of laparoscopic power morcellation has increased the number of reported cases.

Introduction

Uterine leiomyomas are the most common benign pelvic tumors in women; they occur in approximately 25% of reproductive-aged women and are noted on pathologic examination in approximately 80% of surgically removed uteri [1]. Surgery is recommended for symptomatic patients. Although there have been changes in technology and technique, the objectives remain the same: removing disease, minimizing morbidity and preserving fertility.

Leiomyomas are classified according to their location within the myometrium. The International Federation of Gynaecology and Obstetrics (FIGO) identifies eight different types of leiomyoma [2], Group 8 corresponding to those with atypical presentation, including parasitic leiomyoma.

Classically, parasitic leiomyomas have been defined as unusual variants of pedunculated leiomyomas that, for some reason, lie free from the uterus in the abdominal cavity, surviving by obtaining a blood supply from neighboring structures [3]. They may originate from leiomyomas that detach from the uterus and receive a blood supply from adjacent organs or from myoma fragments left in the peritoneal cavity after morcellation of a leiomyoma or the uterus, subsequently taking a blood supply from other organs and growing [4].

The first description of a parasitic leiomyoma was made by Kelly and Cullen in 1909 [5] and in 1951 a case was reported of parasitic leiomyomas in the bladder [6]. In recent years, with the rise of laparoscopic surgery [7], [8], a new type of parasitic leiomyoma has emerged, that with an iatrogenic origin, in particular, as a complication of laparoscopic myomectomy or hysterectomy that require morcellation of the surgical piece to be extracted through a small incision. After morcellation, small fragments of the leiomyoma may remain unnoticed in the abdominal cavity and become implanted and take a blood supply from neighboring structures. They can grow and cause symptoms, but may also be asymptomatic and be diagnosed as an incidental finding on clinical examination. The growth of parasitic leiomyomas seems to be influenced by sex hormones and growth factors, although more research is required to improve our understanding of their development [9].

Despite the attention currently being paid to iatrogenic parasitic leiomyomas, we thought it would be interesting to review all cases of parasitic leiomyomas published to date and assess their association with laparoscopic surgery and morcellation.