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Table of Contents
Year : 2022  |  Volume : 13  |  Issue : 3  |  Page : 182-185

Benign metastasizing leiomyoma: A rarely reported case in low-resource settings

1 Department of Anatomic Pathology, Federal Medical Centre, Abeokuta, Nigeria
2 Department of Obstetrics and Gynaecology, Federal Medical Centre, Abeokuta, Nigeria
3 Department of Morbid Anatomy and Forensic Medicine, Obafemi Awolowo University Teaching Hospital Complex, Ile-Ife, Nigeria

Date of Submission04-Dec-2021
Date of Decision12-Dec-2021
Date of Acceptance24-Dec-2021
Date of Web Publication13-Jul-2022

Correspondence Address:
Dr. Olanrewaju Saheed Jimoh
Department of Obstetrics and Gynaecology, Federal Medical Centre, Abeokuta
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/injms.injms_137_21

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Benign metastasizing leiomyoma (BML) is an uncommon disorder characterized by occurrence of benign smooth muscle tumor with identical features as uterine myoma in extrauterine sites. The most documented site is the lungs, but other areas of the body have been reported. The case of a 44-year-old woman who had BML following an earlier open myomectomy is reported. The presentation mimicked an advanced intra-abdominal tumor with lung involvement, and this posed a diagnostic dilemma, especially with the worsening breathlessness and rapid deterioration of the patient's clinical condition. Autopsy provided an insight into this rare case which was confirmed by histology and immunohistochemistry of the masses in the thoracic and abdominal cavities. BML can easily be misdiagnosed but, if promptly detected, medical and surgical management options could be lifesaving for the affected patients. There is a need for a high index of suspicion in patients who have had previous surgeries for fibroids presenting with pressure symptoms from regions other than the pelvis.

Keywords: Autopsy, benign metastasizing leiomyoma, extrauterine, immunohistochemistry

How to cite this article:
Adeniran AA, Jimoh OS, Omoyiola OZ, Vaughan AT. Benign metastasizing leiomyoma: A rarely reported case in low-resource settings. Indian J Med Spec 2022;13:182-5

How to cite this URL:
Adeniran AA, Jimoh OS, Omoyiola OZ, Vaughan AT. Benign metastasizing leiomyoma: A rarely reported case in low-resource settings. Indian J Med Spec [serial online] 2022 [cited 2023 May 29];13:182-5. Available from: http://www.ijms.in/text.asp?2022/13/3/182/350794

  Introduction Top

Benign metastasizing leiomyoma (BML) is a rare disorder in which benign smooth muscle tumor similar to uterine myoma is found in extrauterine sites in association with previous history of uterine surgeries.[1] This association stems from reported history of previous myomectomy in such individuals in most cases.[2] This entity was first reported in 1939.[1] The disease typically affects women of late reproductive age, and the most common site of metastasis is the lungs (80%), whereas other parts of the body account for the rest (20%).[1],[2]

  Case Report Top

A 44-year-old woman presented to our hospital with a history of progressive abdominal swelling of 4 months and breathlessness of 2 months. The abdominal swelling was not associated with pain, diarrhea, constipation, nausea, or vomiting. There was, however, a history of anorexia, early satiety, and weight loss. The breathlessness was initially with exertion but later progressed to breathlessness at rest. There was a history of nonproductive cough but no hemoptysis. Eleven months prior to this presentation, the patient had an open myomectomy due to symptomatic uterine fibroid with background secondary infertility. She complained of progressive abdominal swelling which was noticed 4 months after the surgery.

Physical examination revealed a middle-aged woman who was in obvious respiratory distress, not pale, acyanotic (on oxygen), anicteric, afebrile, not dehydrated, and nil finger clubbing. There was pitting and nonpainful pedal edema. The respiratory rate was 32 cycles/min with reduced chest movement and air entry on the right. There was a dull percussion note on the right hemithorax, and rhonchi were heard in all the lung zones globally. The abdomen was full and moved with respiration with no area of tenderness. No abdominal organ was palpable. Ascites was demonstrable by fluid thrill. The pulse rate was 88 beats/min (regular and good volume), and the blood pressure was 130/80 mmHg.

An assessment of advanced intra-abdominal tumor with metastasis to the lung was entertained. Computerized tomography scan showed an expansile heterogeneous mass in the right hemithorax with right pleural effusion (suspected malignant mesothelioma) and expansile peritoneal mass. There was also a bulky uterus (likely leiomyomata). Tru-cut biopsy of the right intrathoracic mass suggested fibromyxoid lesion, and open biopsy was advised. The patient was being prepared for exploratory surgery but developed progressive breathlessness and was pronounced dead following failed resuscitation.

Significant findings at autopsy include a huge right intrathoracic mass weighing 2.2 kg and measuring 25 × 20 × 70 cm with a cut surface showing gray-white tissue with whorled pattern and cysts filled with chocolate-colored fluid (altered blood). This intrathoracic mass caused atelectasis of the right lung and compression of the inferior and superior venae cavae as well as the ascending aorta with shifting of the thoracic contents into the left hemithorax. There was pleural effusion in both chest cavities. Seedlings of the gray-white mass were scattered in all the lobes of the right lung.

There was ascites measuring about 900 ml with straw color appearance and also an intra-abdominal mass attached to the mesentery weighing 4 kg with multiple transparent cysts containing straw-colored fluid. The abdominal mass measured 42 × 30 × 9.0 cm, and cut surfaces of the solid components revealed gray-white to tan-colored fleshy tissue with whorled pattern. The uterus had six pedunculated, fleshy masses attached to its body and fundus. Cut surfaces were similar and showed gray-white tissue with whorled pattern.

Microscopic examination of the masses in the right pleural cavity, within the right lung tissues, the abdominal cavity and the uterus were all similar and show proliferating interlacing bundles of smooth muscle cells and admixed fibrocollagenous tissues that are arranged in whorled and haphazard patterns. Areas of hyalinization as well as cystification were present. No atypical feature was seen [Figure 1] and [Figure 2].
Figure 1: Uterine mass demonstrating proliferating bland spindle smooth cells that are interlacing and admixed with fibrocollagenous tissue in haphazard pattern showing no atypia or mitotic activity (H and E, ×400)

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Figure 2: Mass in the lung showing proliferating interlacing bundles of bland, smooth muscle cells with no atypical feature or mitotic activity (H and E, ×400)

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Immunohistochemistry done for caldesmon for smooth muscle stained strongly positive in all the tissues from the aforementioned sites, and proliferative index Ki67 was <5% [Figure 3] and [Figure 4].
Figure 3: Immunohistochemistry strongly positive for smooth muscle marker caldesmon (abdominal mass; ×400)

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Figure 4: Immunohistochemistry strongly positive for smooth muscle marker caldesmon (lung mass; ×400)

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A diagnosis of BML was made as a result of the patient's previous history of myomectomy, findings at autopsy, microscopic histologic examination, and immunohistochemistry staining patterns.

  Discussion Top

BML is a rare disorder first reported by Paul E. Steiner in Chicago, United States of America.[1],[2] As in the case with our patient, individuals with a history of histologically benign uterine leiomyomas present months or years later, with multiple extrauterine nodules of benign smooth muscle cells.[2] The extrauterine leiomyoma is mostly seen in the lungs, with some rare localization in extrapulmonary sites, for example, the abdomen as in this present case.[3] Despite that the specific etiology of BML has not been fully established, hypotheses abound and these include: (i) derivation from a multifocal but independent smooth muscle proliferation, (ii) derivation from a low-grade leiomyosarcoma, and (iii) mechanical dissemination or intravascular spread of existing smooth muscle cells from the uterus to a distant location.[4],[5]

Recent molecular studies have given credence to the above hypothesis with evidence of a clonal relationship between the primary uterine leiomyoma and the extrauterine lesions. This suggests derivation of the extrauterine lesions from a preexisting uterine leiomyoma.[6],[7] In addition, most of the case reports in literatures have shown a history of myomectomy, suggesting that the surgery may have facilitated the dissemination of the primary tumor causing BML.[2],[3],[4],[5] Furthermore, the positivity of hormone receptors (estrogen receptors) and smooth muscle actin also strongly suggests a uterine origin.[8] Importantly, these tumors should be distinguished from a low-grade, indolent leiomyosarcoma; the most helpful pathologic features in making this distinction are the low mitotic index (Ki67) in BML, absence of tumor necrosis, and lack of cellular atypia.[9]

In large number of cases, the tumors are asymptomatic and usually detected incidentally on routine chest X-ray although cough, dyspnea, chest pain, hemoptysis, and decreased pulmonary function have been documented.[10] Other rare clinical presentations based on the extrauterine locations of the tumor have been reported including neurological symptoms.[11] The clinical course of BML varies from chronic asymptomatic to rapid progressive course leading to organ failure and death.[10] It is very important to differentiate BML from malignancies, and the role of radiological tools such as X-ray, computerized tomography scan, and magnetic resonance imaging in diagnosis and management of this disease cannot be overemphasized.[10],[11] Immunohistochemical staining is useful in differentiating BML from other similar lesions with proliferation of smooth muscle cells.[10]

No definitive treatment regimen has been established for BML, and some clinicians have proposed observation and follow-up of selected cases in perimenopausal and postmenopausal women.[10],[12] The duration of observation varies and ranged between 2 months and 16 years.[10] Non-surgical treatments like the use of gonadotropin releasing hormone analogues, selective estrogen receptor modulators, progestogens and aromatase inhibitors have been suggested in non-resectable cases.[10] The aim of the medical therapy is to suppress the circulating level of estradiol.[10],[13] Chemotherapy has not been noted to have a significant influence on the course of the disease in certain cases, and it can be concluded that surgery is still the most effective method in the management of BML with excellent patient tolerance and outcome.[10] Unfortunately, our patient died before any definitive surgery was carried out. Individualized therapy should be considered based on some important prognostic indices such as the hormone receptor status of the patient as well as the site and size of the tumor.[14]

  Conclusion Top

BML warrants close observation and prompt medical or surgical treatment as well as monitoring of the disease progression and response to therapy. Entertaining a high index of suspicion will also help in early case identification and subsequent deployment of appropriate management. Autopsy was able to unravel the mystery of the managing clinicians in this case. Hence, there is an absolute need to re-emphasize the importance of this procedure in regions with firm aversion to autopsy due to social and religious reasons.

Patient consent statement

Consent was taken for this case report as well as for the autopsy and the patient's identity remains anonymous. All the pictures did not involve the privacy of the patient.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Steiner PE. Metastasizing fibroleiomyoma of the uterus: Report of a case and review of the literature. Am J Pathol 1939;15:89-110.7.  Back to cited text no. 1
Barnaś E, Książek M, Raś R, Skręt A, Skręt-Magierło J, Dmoch-Gajzlerska E. Benign metastasizing leiomyoma: A review of current literature in respect to the time and type of previous gynecological surgery. PLoS One 2017;12:e0175875.  Back to cited text no. 2
Lim SY, Park JC, Bae JG, Kim JI, Rhee JH. Pulmonary and retroperitoneal benign metastasizing leiomyoma. Clin Exp Reprod Med 2011;38:174-7.  Back to cited text no. 3
Bakkensen JB, Samore W, Bortoletto P, Morton CC, Anchan RM. Pelvic and pulmonary benign metastasizing leiomyoma: A case report. Case Rep Womens Health 2018;18:e00061.  Back to cited text no. 4
Awonuga AO, Shavell VI, Imudia AN, Rotas M, Diamond MP, Puscheck EE. Pathogenesis of benign metastasizing leiomyoma: A review. Obstet Gynecol Surv 2010;65:189-95.  Back to cited text no. 5
Lee HJ, Choi J, Kim KR. Pulmonary benign metastasizing leiomyoma associated with intravenous leiomyomatosis of the uterus: Clinical behavior and genomic changes supporting a transportation theory. Int J Gynecol Pathol 2008;27:340-5.  Back to cited text no. 6
Wu RC, Chao AS, Lee LY, Lin G, Chen SJ, Lu YJ, et al. Massively parallel sequencing and genome-wide copy number analysis revealed a clonal relationship in benign metastasizing leiomyoma. Oncotarget 2017;8:47547-54.  Back to cited text no. 7
Kayser K, Zink S, Schneider T, Dienemann H, André S, Kaltner H, et al. Benign metastasizing leiomyoma of the uterus: Documentation of clinical, immunohistochemical and lectin-histochemical data of ten cases. Virchows Arch 2000;437:284-92.  Back to cited text no. 8
Bell SW, Kempson RL, Hendrickson MR. Problematic uterine smooth muscle neoplasms. A clinicopathologic study of 213 cases. Am J Surg Pathol 1994;18:535-58.  Back to cited text no. 9
Ki EY, Hwang SJ, Lee KH, Park JS, Hur SY. Benign metastasizing leiomyoma of the lung. World J Surg Oncol 2013;11:279.  Back to cited text no. 10
Matos F, Santiago C, Silva D. Multisystemic benign metastasizing leiomyoma: An unusual condition with an atypical clinical presentation. Case Rep Radiol 2019;2019:7014248.  Back to cited text no. 11
Awonuga AO, Rotas M, Imudia AN, Choi C, Khulpateea N. Recurrent benign metastasizing leiomyoma after hysterectomy and bilateral salpingo-oophorectomy. Arch Gynecol Obstet 2008;278:373-6.  Back to cited text no. 12
Taftaf R, Starnes S, Wang J, Shipley R, Namad T, Khaled R, et al. Benign metastasizing leiomyoma: A rare type of lung metastases – Two case reports and review of the literature. Case Rep Oncol Med 2014;2014:842801.  Back to cited text no. 13
Nasu K, Tsuno A, Takai N, Narahara H. A case of benign metastasizing leiomyoma treated by surgical castration followed by an aromatase inhibitor, anastrozole. Arch Gynecol Obstet 2009;279:255-7.  Back to cited text no. 14


  [Figure 1], [Figure 2], [Figure 3], [Figure 4]


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