Benign metastasizing leiomyoma: a rare cause of multiple pulmonary nodules

A comprehensive review of benign tumors in the lung

PURPOSE OF REVIEW

The purpose of this review is to provide clinicians a comprehensive overview of the epidemiology, clinical symptoms, radiological features, pathological features, and management recommendations for the vast majority of benign lung tumors. Benign lung tumors are very rare with incidence ranging from 1 in 1000 to 1 in 1 million. Despite not being malignant, certain benign tumors carry significant morbidity and mortality along with diagnostic challenges.

RECENT FINDINGS

Advancements in genomic sequencing have led to discovery of mutations in particular benign lung tumors. Improved genotyping have aided the diagnosis of certain tumors and the identification of lung lesions with malignant transformation potential. Genomic understanding has also led to targeted therapy for tumors with significant morbidity.

SUMMARY

Despite radiographic and pathologic advances in understanding benign lung tumors, the paucity of cases continues to impact management recommendations and early detection. Global collaborative initiatives in compiling and analyzing cases are essential for stronger evidence based management recommendations.

A 52-Year-Old Woman With Persistent Back Pain and Multiple Pulmonary Nodules

CASE PRESENTATION

A 52-year-old woman with a history of leiomyoma uteri and tobacco-use disorder in remission presented with 2 months of progressive back pain. Her pain was located between her shoulder blades and was described as constant with intermittent sharp, stabbing sensation. It was nonradiating and aggravated by inspiration. She denied fever, cough, shortness of breath, chest pain, or recent changes in weight or appetite. Two days prior, she was evaluated in the ED for similar symptoms and prescribed naproxen and cyclobenzaprine for suspected musculoskeletal pain. However, she received minimal relief, which prompted her visit. She underwent a total hysterectomy 13 years ago for benign uterine fibroid tumors. She had a 15-pack-year history but quit smoking 3 years ago. Family history was notable for colon and pancreatic cancer in her father and breast cancer in her maternal aunt.

Pulmonary Benign Metastasizing Leiomyoma in a Postmenopausal Woman: A Case Report and Review of the Literature

Pulmonary benign metastasizing leiomyoma (PBML) is a rare condition characterized by the spread of uterine leiomyomas to the lungs, typically observed in premenopausal women with a history of hysterectomy or myomectomy. This report presents a unique case of a postmenopausal woman, aged 65, that emphasizes the clinical, radiological, histologic, and immunohistochemical aspects of the disease. On presentation, the patient suffered from severe pain. On imaging, a sizable lung tumor was found. Histopathological examination and immunoprofiling confirmed PBML. The patient underwent various treatments, including surgery, radiation therapy, and hormonal therapy, illustrating the challenges in managing PBML. A literature review underscores the rarity of PBML and its diverse clinical manifestations. This study provides valuable insights into the complexities of PBML.

Benign metastasising leiomyoma: a rare disease and a diagnostic challenge

Benign metastasising leiomyoma (BML) is a rare tumour characterised by extrauterine metastasis of histologically benign leiomyomas. We present a case of BML with pulmonary involvement. A 49-year-old woman presented with large pelviabdominal masses complicated by gross abdominal and lower limb swelling 6 years following open myomectomy. Preoperative CT imaging showed pelviabdominal masses and multiple bilateral pulmonary nodules. Initial impression was that of a stage 4 gynaecological malignancy. Palliative total hysterectomy bilateral salpingo-oophorectomy was performed. Histopathology confirmed benign uterine leiomyomas. Biopsy of pulmonary nodules showed benign leiomyomas, strongly positive for oestrogen and progesterone receptors. Definitive diagnosis of BML was made on histopathology and immunohistochemistry. The patient declined letrozole treatment as she had just undergone bilateral oophorectomy. She opted for conservative monitoring of her lung nodules. CT imaging 7 months postsurgery showed disease regression. She will require long-term surveillance scans to detect disease progression.

Benign Metastasizing Leiomyomatosis to the Skin and Lungs, Intravenous Leiomyomatosis, and Leiomyomatosis Peritonealis Disseminata: A Series of Five Cases

Benign metastasizing leiomyomatosis (BML) is a rare disease that typically occurs in women with a history of uterine leiomyomatosis. Benign metastasizing leiomyomatosis occurs more frequently in the lungs but may also develop in other organs and tissues. Other unusual variants of extra-uterine leiomyomatosis include intravenous leiomyomatosis (IVL) and leiomyomatosis peritonealis disseminata (LPD). In this article, three cases of BML are presented. One case, in a premenopausal woman, presented cutaneous metastases. We also present a case of IVL and a case of LPD, which occurred in postmenopausal women. Given the rarity of BML, IVL, and LPD, the authors reviewed the literature and herein discuss the implications for treatment in all five cases. Evidence for treating BML, IVL, and LPD is still scarce, and data available from our series and other small series seem to point to the patient’s hormonal status playing a fundamental part in the treatment plan. Furthermore, a collecting bag when performing excision of uterine leiomyomas may help avoid the potential spreading of leiomyomatosis. Hysterectomized patients with chronic cough, frequent respiratory infections, abdominal discomfort, right heart failure, or non-specific symptoms should be actively screened for BML, IVL, and LPD. Treatment should be individualized according to each patient’s hormonal status and desires.

Metastatic uterine fibroid in postmenopausal woman suspected of leiomyosarcoma: A case report and literature review

Benign metastatic leiomyoma is a unique event presenting most commonly in premenopausal women especially those with a previous history of gynecological surgery as management of uterine fibroids. In this case report, we investigate a rare case of benign metastatic leiomyoma in a 54-year-old postmenopausal female presented with a huge pelvic mass that was rapidly growing along with pulmonary nodules. The patient is suspected to have leiomyosarcoma which is eventually confirmed pathologically as benign metastatic leiomyoma. Although rare, describing the challenging diagnostic and management approach of such entity is essential and to consider it one of the differential diagnoses of patients who present with similar history.

Benign Metastasizing Leiomyoma in the Lung Presenting in a Phyllodes-Like Pattern Mimicking a Biphasic Tumor: A Case Report

Primary biphasic tumors of the lung are rare. Lung lesions with a biphasic pattern are far more commonly primary or metastatic soft tissue tumors with entrapped native respiratory epithelium, giving the false impression of a biphasic tumor. We report a case of bilateral benign metastasizing leiomyomas in a 69-year-old female where the tumor cells diffusely entrapped native respiratory glands in a phyllodes-like pattern. The radiographic characteristics and histologic appearance were not immediately diagnostic and covered a wide differential. Reaching the final diagnosis required the use of immunohistochemical studies as well as correlation with the patient's history and radiographic findings. To the best of our knowledge, this is the first report of pulmonary benign metastasizing leiomyoma presenting in a phyllodes-like pattern. This case illustrates the importance of considering entrapment of native lung epithelium in the differential diagnosis of biphasic-appearing lung tumors.

Benign Metastasizing Leiomyoma of the Uterus with Pulmonary and Bone Metastases

Benign metastasizing leiomyoma (BML) is a rare spindle cell neoplasm seen in middle-aged women who have a history of leiomyoma of the uterus. The most common sites of metastases are the lungs; however, other sites of spread have been documented. These tumors by definition have no malignant features on histology and tend to be estrogen and progesterone positive. We present a middle-aged woman who was incidentally found to have multiple pulmonary nodules and a mass on her sternum after she was involved in a motor vehicle accident. She had a history of uterine leiomyoma and had undergone a hysterectomy ten years prior to the accident. Biopsies were performed of the lung nodules and sternum mass and compared to her hysterectomy specimen, and they were identical, and hence, she was diagnosed with BML. Due to the growing tumor of her sternum, she was started on tamoxifen with stability of her tumors. These tumors, since they are benign, tend to have an indolent course. However, in the instances that treatment is warranted, options include surgery or antiestrogen therapy. We will be discussing the pathogenesis, histological findings, and treatment options of this rare condition. Our case is unique because BML in general do not tend to spread to multiple organs and tend to be limited to one site of disease.

Cardiac metastasizing leiomyoma: A case report

INTRODUCTION

Cardiac intracavitary growth of metastasizing tumour is unusual. Benign Metastasizing Leiomyoma (BML) from the uterus to the heart is extremely rare. It affects premenopausal women with a history of uterine leiomyoma.

PRESENTATION OF CASE

We report a case of a 42-year-old woman who presented three tumours in the right side of the heart, two years after a hysterectomy due to leiomyomatosis. The cardiac tumours were resected and the diagnosis was uterine leiomyoma.

DISCUSSION

The patient developed cardiac failure due to three masses at the right side of the heart. Cardiac involvement in BML is usually asymptomatic and rare. The heart masses were surgically removed and a peri ovarian mass was detected and also removed. Although histologically benign, BML exhibits metastatic qualities.

CONCLUSION

It suggests that BML should be included as a differential diagnosis when a female patient presents an intra cardiac mass and a history of hysterectomy.

Pulmonary benign metastasizing leiomyomas: a case series of 23 patients at a single facility

Background

Pulmonary benign metastasizing leiomyoma (PBML) is a rare disease characterized by leiomyoma of benign histopathology existing in the lungs. Because of its rarity, limited literature with a single case or small number of cases has been regarding to the clinical course, pathology or management of PBML.

Methods

A retrospective study was performed of all PBML cases diagnosed and managed at Peking Union Medical College Hospital (PUMCH) from 2001 to 2019. The clinical characteristics, pathology, treatment and outcomes of each case were studied.

Results

There were 25 PBML patients identified in the 19-year period in PUMCH, and 23 patients’ data was analyzed. The median age at diagnosis was 46 years. There were 7 patients (30.4%) diagnosed with postmenopausal status. Two patients (8.7%) had no uterine leiomyoma, and 3 patients (13.0%) had no gynecologic surgery history. Immunohistochemistry of most lesions demonstrated positive for desmin, SMA and Estrogen/Progesterone Receptors; and negative for S-100 were shown in 7 cases. After curative or diagnostic surgeries for the PBML, several treatments from observation to medical or surgical castration were performed. Nine premenopausal patients preserved their ovaries at first. At a median follow-up of 8 years, 3 patients finally had oophorectomy.

Conclusions

PBML is a rare disease and should be treated by individualization according to the patients’ age, symptoms and extent of lesion. Curative surgery for patients with limited lesions can achieve the complete response. For patients that are young and asymptomatic, close observation is recommended as the first choice. All patients should undergo long-term surveillance.

Benign metastasizing leiomyoma in femur and thigh with a history of uterine leiomyoma: A case report and literature review

Benign metastasizing leiomyoma (BML) is a rare disease that is characterized by well-differentiated smooth muscle tumors occurring extrauterine site in women with a history of uterine leiomyoma. The lung is the most common metastatic site for BML. A 48-year-old woman, who had histories of laparoscopic myomectomy and transabdominal total hysterectomy, visited an orthopedics complaining of a mass in her left thigh and difficulty in walking. Magnetic resonance imaging (MRI) and fluorine 18 fluorodeoxyglucose positron emission tomography/computed tomography revealed multiple mass lesions in her both thighs and left femur as well as both lungs. She was referred to our hospital for further examination. We diagnosed her tumors as BML according to histopathological analysis of tumor specimen. The left thigh tumor was resected and the treatment with gonadotropin releasing hormone agonist regressed the size of the residual tumors by approximately 30%. BML should be considered when multiple soft tissue tumors are found in women with a history of leiomyomas.

Co-presentation of pulmonary arteriovenous malformation (PAVM) and multifocal benign metastasizing leiomyoma (BML) of lungs: Diagnostic dilemma and successful endovascular treatment

A 50-year-old female with a 20-year history of multifocal pulmonary benign metastasizing leiomyoma (BML), and asthma presented with subacute worsening of chronic dyspnea. A contrast-enhanced computerized tomography of the chest showed a single 1.4 × 1.5-cm contrast-enhancing mass in the right lower lobe among numerous non-enhancing bilateral pulmonary BML lesions. Pulmonary angiogram was not performed at that time due to clinical improvement. Four years later, the patient presented with refractory subacute worsening of her chronic dyspnea and was referred for embolization of the pulmonary arteriovenous malformation (PAVM). Two feeder arteries to the PAVM were embolized; each with a 6-mm Amplatzer-IV vascular plug and a 4-mm Nester coil. Follow-up angiograms demonstrated no flow through the PAVM. The patient's dyspnea resolved and she remained asymptomatic at one-year follow-up.

Cancer Genes Mutations in Benign Metastasizing Leiomyoma: A Case Report

Benign metastasizing leiomyoma is a very uncommon clinicopathologic entity with unknown molecular pathogenesis. We present a case of a 40-year-old woman who has a history of surgical resection of a large uterine leiomyoma and then subsequently presented with benign metastasizing leiomyomas to her lungs. Due to her tumor being estrogen receptor (ER) positive and progesterone receptor (PR) positive, she was empirically treated with anastrozole with sustained clinical benefit. Molecular studies with Foundation One testing showed low mutational burden and mutational variants in five known cancer genes. Our findings have important clinical and pathogenetic implication for metastasizing uterine leiomyoma.

Multisystemic Benign Metastasizing Leiomyoma: An Unusual Condition with an Atypical Clinical Presentation

Benign metastasizing leiomyoma (BML) is a rarely found entity with few documented cases in the literature, usually occurring in women of reproductive age with a history of myomectomy or hysterectomy. The leiomyomas can metastasize to several organs, the lungs being the most commonly affected. We report a case of a 40-year-old female patient who presented at our institution with low back pain. She underwent a lumbar MR that revealed the presence of an expansive and compressive mass in the body of L4. This mass was biopsied, corresponding to a metastasizing leiomyoma with no malignant characteristics. Subsequently, a CT examination showed several soft tissue density round masses in both lungs, but the most striking feature was a 12 cm mass located in the left iliac crest. There was asymmetrical uterus enlargement, caused by the presence of several leiomyomas. Since the lesions were estrogen and progesterone positive, hormone suppression consisting of oophorectomy followed by anastrozole was the chosen treatment. No signs of progression were observed at the 6-month follow-up. This case is one of the very few that occurred in a woman with no previous uterine intervention, adding further evidence that surgery is not an essential condition for this entity to develop.

Pulmonary benign metastasizing leiomyoma: A case report

Uterine leiomyoma is the most common benign gynecological tumor. Rarely, it has benign extra-uterine growth patterns, including benign metastasizing leiomyoma (BML), with lungs being the most common metastatic site.

We present a case of a 47-year-old female who, 3 years prior to presentation, underwent abdominal supra-cervical hysterectomy for benign leiomyoma. Approximately 6 months prior to presentation, she was seen for shortness of breath and chest pain. A CT of the chest revealed multiple new non-calcified pulmonary nodules bilaterally. PET/CT demonstrated mild FDG uptake in multiple lung nodules, with no significant extra-thoracic sites of abnormal FDG uptake. A CT guided lung biopsy showed a low grade, smooth muscle tumor. Immunohistochemical staining was positive for smooth-muscle actin and desmin, estrogen and progesterone receptor and was negative for CD117, HMB-45, CD34, pan cytokeratin and EMA. She underwent wedge resection of one of the nodules which confirmed the above findings. A cytogenetic analysis was also performed, which was consistent with pulmonary BML. She ultimately underwent left lower lobe resection and was started on a daily aromatase inhibitor.

BML is a rare disease usually seen in women of reproductive age. The pathogenesis and treatment remain controversial. BML mostly tends to have an indolent course and a favorable outcome.

Pelvic and pulmonary benign metastasizing leiomyoma: A case report

Seven years after she had a total abdominal hysterectomy for benign leiomyomas, a 46-year-old woman presented with a pelvic mass and multiple pulmonary nodules. She underwent resection of the mass and core needle biopsy of a pulmonary lesion. Histopathologic analysis revealed that both the pelvic and the pulmonary lesions were consistent with benign leiomyomas. Benign metastasizing leiomyoma should be considered if a woman of reproductive age and with a history of leiomyomas presents with extrauterine nodules without evidence of malignancy. The final diagnosis should be based on histopathological examination. Treatment depends on tumor size, location, receptor positivity, and disease progression.

Pulmonary metastasectomy in uterine malignancy: outcomes and prognostic factors

Metastatic uterine cancer is a form of systemic disease. As for other solid tumours, it is advocated by some authors that in selected patients, lung metastasectomy may play a role in long-term disease control. The practice of lung metastasectomy is however open to criticism as there is lack of convincing evidence, and over-encouraging outcomes may be attributed to intrinsic selection bias. The case of metastatic uterine tumours is reviewed in the light of the available literature, in order to identify common patterns and prognostic factors that may influence and determine an individualised and informed patient decision.

Benign metastasizing leiomyoma: A review of current literature in respect to the time and type of previous gynecological surgery

INTRODUCTION

Benign metastasizing leiomyoma (BML) is a rare disorder that affects women with a history of uterine leiomyoma, which is found to metastasise within extrauterine sites. The aetiology of BML remains unexplained. Because BML is rare, and most publications contain descriptions of single cases, no statistically determined time relations were found between the primary and secondary surgeries, which may have aetiological implications.

OBJECTIVES

To determine age before BML surgery, age during diagnosis of BML, type of prior surgery, and location of metastasis based on the literature.

METHODS

A systematic review of four databases (Medline/PubMed, Embase, Web of Science, and Cochrane) covering articles published from 1 January 1965 to 10 April 2016. The inclusion criteria were full-text articles in English and articles containing case reports. Articles in languages other than English (39), articles containing incomplete data (14), i.e. no information regarding the time of surgery and/or the site of metastasis, articles bereft of case studies (25), and articles with access only to summaries, without access to the complete text (10) were excluded. Of 321 titles identified, only 126 articles met the aforementioned criteria.

RESULTS AND CONCLUSIONS

The mean age during primary surgery and BML diagnosis was 38.5 years and 47.3 years, respectively. The most common surgery was total hysterectomy. The most frequent site of metastasis was the lungs; other organs were affected less frequently.The site of metastases and their number were not related to the longer time span between the patient's initial surgery and occurrence of metastasis. The analysed data, such as the age during primary surgery, age during BML diagnosis, site and type of metastasis, do not provide us a clear answer. Thus, BML pathogenesis is most probably complex in nature and requires further multidirectional research.

Pierre J, Gala R. Recurrent Pneumothoraces in a Patient With Pulmonary Benign Metastasizing Leiomyoma

BACKGROUND

Pulmonary benign metastasizing leiomyoma (BML) is a rare disease with a malignant characteristic of spread from the uterus. Most cases are asymptomatic, and only 1% are associated with pneumothorax.

CASE REPORT

We present the case of a 42-year-old female with recurrent pneumothoraces leading to an incidental finding of diffuse bilateral pulmonary nodules. The diagnosis of BML was based on the patient's history of uterine leiomyomata and confirmed by a biopsy showing benign smooth muscle staining for desmin and vimentin.

CONCLUSION

BML should be considered in women with a history of leiomyomata who develop pneumothoraces resulting from peripheral pulmonary nodules. A standardized treatment regimen has yet to be established, and therapy plans require a multidisciplinary approach, involving gynecology, cardiothoracic surgery, and pulmonology.

Cystic Benign Metastasizing Leiomyoma of the Lung Mimicking Hydatid Cyst

A 60-year-old woman, with history of a resected uterine benign leiomyoma, is operated for a cystic lesion in the left lung, mimicking an hydatid cyst, and confirmed histologically as Cystic Benign Metastasizing Leiomyoma.

Benign metastasizing leiomyoma in triple location: lungs, parametria and appendix

Benign metastasizing leiomyoma (BML) usually are situated in one organ, most often in lungs. BML patients typically have a history of uterine leiomyoma treated with hysterectomy, myomectomy or subtotal hysterectomy. The aim of the study was to present the case of a 53-year-old woman with triple location in the lungs, parametria and appendix. She had undergone a myomectomy 26 years earlier. In 2015, she was admitted to the surgical department because of abdominal pain, whereupon a cholecystectomy was performed. CT scans showed pelvic mass with pulmonary metastasis. Upon discharge the patient was referred to the Gynecology Clinic, where a laparotomy was performed. The intraoperative findings were: 1) uterus with multiple leiomyomas, 2) four tumors in the parametria, 3) tumor connected to the appendix. A subtotal hysterectomy, with a bilateral salpingo-oophorectomy, removal of the tumors from the parametria and appendectomy was performed. Pathology confirmed the diagnosis based on morphology and immunohistochemical staining (strongly positive for estrogen receptors and SMA, while Ki67 was very low, below 1%). Upon postoperative recovery, the patient was referred to the Thoracic Surgery Department. During the thoracotomy, multiple nodes, surrounded by lung parenchyma, were revealed. Wedge resection was performed, for localized pulmonary lesions, and sent for pathological examination. The final pathological diagnosis was benign metastasizing leiomyomatosis.

In conclusion, the triple location of BML could possibly be a result of a parallel different metastasizing mechanism, although it is impossible to exclude one mechanism, which may be the cause of the metastases in three locations.

Benign metastasizing leiomyomatosis (BML): A rare cause of cavitary and cystic pulmonary nodules

Benign metastasizing leiomyomatosis (BML) is a rare cause of pulmonary lesions found in reproductive age women who have undergone a hysterectomy for uterine leiomyoma. Given the relative rarity of the disease, the management of these lesions varies from surgical (oopherectomy) or medical antiestrogen hormonal therapy to clinical observation and survelliance. The disease generally presents asymptomatically with multiple, well-defined pulmonary nodules discovered incidentally on imaging. We report an atypical presentation of a 46-year-old woman with incidentally found bilateral pulmonary cavitating nodules and cysts, concerning for lymphangioleiomyomatosis (LAM), who was ultimately diagnosed with BML.

Benign metastasizing leiomyoma of the lung: A case report and literature review

Pulmonary benign metastasizing leiomyoma (BML) is a rare event characterized by benign soft-tissue tumors that occur when uterine leiomyomas metastasize to the lung. The present study reports the case of a 47-year-old female patient who presented with multiple bilateral pulmonary nodules on a chest X-ray during a health checkup nine years after a hysterectomy due to uterine fibroids. Chest computed tomography (CT) revealed multiple well-defined nodular shadows in the lung. One tumor of the left upper lung was resected by thoracoscopic surgery. Pathologically, the resected lesion consisted of benign spindle cells and was diagnosed as BML. The post-operative course was uneventful. Other lung nodules have been meticulously monitored at follow-up, and repeat CT two years later showed that these nodules had not increased at all in size and that no new lobe nodules had appeared. The present study indicates that pulmonary BML occurs in a low proportion of female with a history of uterine leiomyoma and treatment methods for it are diverse and controversial.

An unusual cause of pulmonary nodules in the emergency department

We report a 51-year-old woman who presented to the emergency department with left-sided pleuritic chest pain 2 weeks after subtotal hysterectomy and bilateral salpingo-oophorectomy for a leiomyomatous uterus. Computed tomography scan of the chest revealed bilateral pulmonary nodules. Biopsy showed cytologically bland spindle cells without overt malignant features. Immunohistochemistry confirmed smooth muscle phenotype, in keeping with a clinicopathologic diagnosis of benign metastasizing leiomyoma (BML). BML does not frequently come to the attention of the emergency physician because it is rare and usually asymptomatic. When symptomatic, its clinical presentation depends on the site(s) of metastasis, number, and size of the smooth muscle tumors. Emergent presentations of BML are reviewed.

Benign metastasizing leiomyoma of the lung

Benign leiomyomas of the uterus are uncommonly found in association with benign smooth muscle tumors beyond the confines of the uterus. Benign metastasizing leiomyoma (BML) is a rare disease in which the lung is described to be the most afflicted extrauterine organ. We present a brief review of the literature, along with case reports for four patients who were followed up after resection of a pulmonary lesion or after pathological confirmation by biopsy. The clinical course of BML varies from chronic asymptomatic appearance to rapid progression, leading to respiratory failure and death. Our BML patients did not complain of pulmonary symptoms, such as cough, dyspnea, or chest tightness. Pathology revealed benign leiomyomas with no atypia and mitotic activity <5 per 10 high-power field. Immunohistochemical staining was positive for actin and desmin. A standard treatment for BML has not yet been established. Because of the hormone-sensitive characteristics of BML, treatments are based on hormonal manipulation along with either surgical or medical oophorectomy. Benign metastasizing leiomyoma can be observed in postmenopausal women. We observed four patients who did not receive adjuvant hormonal therapy because they were postmenopausal or perimenopausal. All patients are still healthy and show no evidence of recurrence or progression of the disease.

Surgical removal of an intravenous leiomyoma with intracardiac extension and pulmonary benign metastases

Intravenous leiomyomatosis (IVL) with right intracardiac extension or pulmonary benign metastases (PBM) is rare. We report a case of 51 year-old woman, who underwent successful extensive double stage surgical removal of the intracardiac IVL extension associated with a pulmonary limited resection where the cystic bullae and PBM were found, and a month later gynaecological operation. To our knowledge this is the first reported case of such a combination.

Uterine-specific loss of Tsc2 leads to myometrial tumors in both the uterus and lungs

Lymphangioleiomyomatosis (LAM) is a rare disease characterized by proliferation of abnormal smooth-muscle cells in the lungs, leading to functional loss and sometimes lung transplantation. Although the origin of LAM cells is unknown, several features of LAM provide clues. First, LAM cells contain inactivating mutations in genes encoding Tsc1 or Tsc2, proteins that limit mTORC1 activity. Second, LAM tumors recur after lung transplantation, suggesting a metastatic pathogenesis. Third, LAM is found almost exclusively in women. Finally, LAM shares features with uterine leiomyomas, benign tumors of myometrial cells. From these observations, we proposed that LAM cells might originate from uterine leiomyomas containing Tsc mutations. To test our hypothesis, and to develop mouse models for leiomyoma and LAM, we targeted Tsc2 deletion primarily in uterine cells. In fact, nearly 100% of uteri from uterine-specific Tsc2 knockout mice developed myometrial proliferation and uterine leiomyomas by 12 and 24 weeks, respectively. Myometrial proliferation and mTORC1/S6 activity were abrogated by the mTORC1 inhibitor rapamycin or by elimination of sex steroid production through ovariectomy or aromatase inhibition. In ovariectomized Tsc2 null mice, mTORC1/S6 activity and myometrial growth were restored by estrogen but not progesterone. Thus, even without Tsc2, estrogen appears to be required for myometrial mTORC1/S6 signaling and proliferation. Finally, we found Tsc2 null myometrial tumors in lungs of older Tsc2 uterine-specific knockout females, suggesting that lung LAM-like myometrial lesions may indeed originate from the uterus. This mouse model may improve our understanding of LAM and leiomyomas and might lead to novel therapeutic strategies for both diseases.

Benign metastasizing leiomyoma of the lung: report of a case

A 35-year-old female presented with multiple bilateral pulmonary nodules on a chest X-ray during a regular health checkup. Chest computed tomography revealed multiple well-defined nodular shadows in the lung. She had undergone a myomectomy 7 years previously for leiomyoma of the uterus. Thoracoscopic resection of one of the nodules was performed to establish a pathological diagnosis. Pathological findings were consistent with benign metastasizing leiomyoma. Estrogen and progesterone receptors showed strong positives by immunohistostaining of the tumor. The patient is currently receiving outpatient treatment for a benign metastasizing leiomyoma by administration of a GnRH analog drug.