Pulmonary benign metastasizing leiomyoma presenting as acute hypoxemic respiratory failure: a case report

Abstract

Pulmonary benign metastasizing leiomyoma is an uncommon condition, predominantly affecting women of childbearing age with a history of uterine smooth muscle tumors and uterine leiomyoma surgery for uterine leiomyoma. The progression of PBML is often unpredictable and depends on the extent of lung involvement. Generally, most patients remain asymptomatic, but a minority may experience coughing, wheezing, or shortness of breath, which are frequently misdiagnosed as pneumonia. consequently, this presents significant challenges in both treatment and nursing care before diagnosis. This paper reports the case of a 35-year-old woman primarily diagnosed with acute hypoxic respiratory failure who was transferred from the emergency room to the intensive care unit. The initial computed tomography scan of the patient’s lungs indicated diffuse interstitial pneumonia, but the sequencing of the alveolar lavage fluid pathogen macro did not detect any bacteria, fungi, or viruses. Moreover, the patient remained in a persistent hypoxic state before the definitive diagnosis. Therefore, our focus was on maintaining the airway patency of the patient, using prone ventilation, inhaling nitric oxide, monitoring electrical impedance tomography, and preventing ventilator-associated pneumonia to improve oxygenation, while awaiting immunohistochemical staining of the patient’s biopsied lung tissue. This would help us clarify the diagnosis and treat it based on etiology. After meticulous treatment and nursing care, the patient was weaned off the ventilator after 26 days and transferred to the respiratory ward after 40 days. This case study may serve as a reference for clinical practice and assist patients suffering from PBML.

Introduction

Pulmonary benign metastasizing leiomyoma (PBML) is a rare form of lung disease, typically occurring in women of childbearing age with a history of uterine leiomyoma who have undergone surgery for uterine fibroids [1]. The onset of PBML is very subtle, and patients may experience coughing, expectoration, shortness of breath, or no symptoms at all. Hence, it is mostly detected during examinations for other diseases [2]. Acute hypoxemic respiratory failure (AHRF) is a common life-threatening disease in emergency rooms, necessitating the selection of different oxygen therapies based on varying degrees of severity. It is the most frequent reason for intensive care unit (ICU) admission in patients with benign metastatic smooth muscle tumors of the lung, carrying a mortality rate close to 30% [3].

Herein, we present a case of a patient with PBML and AHRF who suffered from persistent hypoxemia, pulmonary imaging, and physicochemical diagnosis in the ICU. Thus, nursing care was challenging in terms of airway management and enhancing oxygenation.

Case description

Case presentation

A 35-year-old woman was admitted to a hospital with PBML in October 2023. She had a history of present illness including fever, chest tightness, shortness of breath accompanied by cough and expectoration, and other discomforts half a month ago. Computed tomography (CT) performed at another hospital showed that the lungs exhibited diffuse multiple patchy fuzzy shadows (Fig. 1). The patient received antiviral and anti-infective treatment for lung lesions before being transferred to our hospital. Upon arrival at the emergency room, she was conscious and using nasal high-flow oxygen inhalation, with an inspired oxygen fraction (FiO₂) of 90%, airflow at 60 L/min, oxygen saturation (SpO₂) at 88%, and blood gas analysis results showing: PH: 7.48, PO₂ 52.5 mmHg, PCO₂ 36 mmHg. Laboratory tests revealed high-sensitivity C-reactive protein at 5.28 mg/L and procalcitonin at 0.02 ng/mL. The patient had a history of cesarean Sect. 5 years prior. Considering that patients with acute hypoxic respiratory failure require immediate mechanical ventilation, they were transferred to the ICU for further treatment.

Fig. 1

Diffuse multifocal patchy blurred shadows in both lungs

Disease progression and treatment

Upon the patient’s admission to the ICU, her vital signs were as follows: T 36℃, HR 92 beats/min, RR 20 breaths/min, BP 134/81 mmHg (1 mmHg = 0.133 kPa), SpO₂ 82%. At this time, the parameters for high-flow nasal oxygen were adjusted to an FiO₂ of 100% and an airflow of 50 L/min. Blood gas analysis results showed that PH 7.49, PO₂ 57 mmHg, PCO₂ 41 mmHg, oxygenation index (PO₂/FiO₂) 57 mmHg. Awake-prone positioning ventilation can reduce the intubation rate among patients suffering from AHRF [4]. Therefore, conscious prone position ventilation was performed. After 13 h in the prone position, oxygenation did not improve, and nitric oxide inhalation therapy was administered because it could enhance the function of alveolar type II epithelial cells, expand pulmonary microcirculation, increase pulmonary blood perfusion, reduce pulmonary artery pressure, improve the ventilation/blood ratio, alleviate lung injury, and consequently increase the oxygenation index [5]. Following 2 h of nitric oxide inhalation therapy, the patient’s oxygenation slightly improved, and the oxygen concentration was reduced to 70%. However, the patient’s respiratory status deteriorated after 18 h, leading to tracheal intubation. Pulmonary electrical impedance tomography (EIT) is a non-invasive, continuous, dynamic, and non-radiative lung ventilation monitoring technology. It primarily detects changes in thoracic bioelectrical impedance during ventilation by applying weak current from local electrodes and uses the corresponding imaging algorithm to monitor pulmonary ventilation function. EIT has been extensively utilized in the diagnosis and treatment of critically ill patients [6]. Lung ventilation distribution was clarified by using electrical impedance tomography for targeted prone ventilation. Many conditions could cause acute respiratory failure, but we have ruled out these diseases through a series of tests. This includes an alveolar lavage fluid pathogen metagenomic sequencing test that reported that no bacteria, Fungi, and viruses were detected from bilateral lung lesions after completing immunological and toxicity-related tests. The patient’s persistent hypoxemia did not improve, so a diagnostic lung biopsy was carried out on the 9th day of admission to the ICU. A tracheotomy was performed on the 10th day because the patient could not be taken off the machine within a short period and to reduce ventilator-associated pneumonia. Histological diagnosis by lung puncture on the 13th day suggested a spindle cell soft tissue tumor. and in combination with immunohistochemistry, smooth muscle neoplasia was considered first (Fig. 2). considering the patient is a woman of childbearing age, the family history was asked again. As a result, the cesarean section and the removal of uterine fibroids were revealed. After that, a transabdominal gynecological ultrasound and a low echo mass in the uterine fundus, which was considered to be uterine fibroids. Combined with the patient’s reproductive hormone detection and clinical manifestations, the patient was finally diagnosed with PBML. On the 17th day, mifepristone tablets were given for hormone reduction treatment. On the 24th day, tracheotomy combined with high-flow offline treatment was started. On the 40th day, the patient was transferred to the respiratory medicine ward. On the 52nd day, the patient recovered and was discharged. Nurses performed dynamic monitoring to guide lung rehabilitation according to arterial blood gas analysis results during treatment in the ICU (Fig. 3). After a follow-up of 1-month, the patient was recovering well and had no pulmonary symptoms.

Fig. 2

Spindle cell soft tissue tumors, combined with immunohistochemistry, smooth muscle neoplasia first considered

Fig. 3

Blood gas analysis results at key points during the intensive care unit stay. Annotation: The oxygenation index is the PaO₂: fraction of inspired oxygen ratio

Ethics statement

The study was approved by the hospital’s medical ethics committee. Written consent was obtained from the patients for this study before publication.

Discussion

There are few case reports on PBML, and it generally occurs from 3 months to 26 years after surgical resection of uterine fibroids [7]. Besides, the majority of patients with PBML would have solid pulmonary nodules suggested by CT of the lungs [8]. In contrast, this paper reports that both lungs of the patient showed interstitial pneumonia, which is easy to be misdiagnosed as pneumonia. Therefore, lung tissue usually should be taken for pathological diagnosis. It is reported in the literature that PBML patients generally have no subjective symptoms and are often found accidentally by physical examination or preoperative examination. A few patients may have symptoms such as cough, chest tightness, and shortness of breath [9]. Wu et al. reported 7 cases of PBML in Jiangsu, China, of which 5 had no obvious symptoms, 1 was dyspnea, and 1 was chest tightness and urgency. Among them, 6 patients received surgical treatment and 1 patient received radiofrequency ablation. The prognosis was good, and no recurrence was reported after 3 to 69 months of follow-up [10]. Hao et al. summarized the clinical characteristics of 65 PBML patients based on previous literature, among which 28 were asymptomatic, 20 had dyspnea, 10 had cough, 2 had chest pain/chest distress, 5 had pneumothorax, 3 had hemoptysis, and 1 had back pain. No cases of sudden severe hypoxic respiratory failure were reported [1]. The patient was healthy previously and the first manifestation was chest tightness, shortness of breath, and persistent hypoxemia. The diagnosis of PBML is very difficult, the condition is urgent, and there are strict pathological diagnostic criteria. Therefore, improving oxygenation during acute hypoxic respiratory failure poses a challenge to nursing care. Rarely, the patient was tolerant to continuous hypoxia, with no cyanosis at the fingertips, no tachycardia, and no wet rales on bilaterally auscultation. To avoid tracheal intubation, we chose to wear nasal high flow while awake prone position ventilation when the patient developed AHRF. The HFNC therapy could match the inspiratory needs closely of the patient through high-flow airflow to avoid lung injury caused by excessive respiratory drive. Moreover, the HFNC therapy could provide stable FiO₂ relatively, effective temperature, and humidity, which helps the patient to increase comfort and secretion clearance [11]. On the other hand, HFNC would more comfort and tolerance compared to non-invasive ventilation for awake patients. The awake prone position ventilation could improve ventilation/perfusion and increase lung compliance to facilitate the secretion expulsion through the airway [12]. During the treatment of awake prone position ventilation combined with HFNC, the patient was advised to use nasal closed-mouth breathing and assessed the effectiveness of oxygen therapy in one hour. What’s more, the patient could express the comfort of a prone position actively because she had consciousness and spontaneous breathing ability, it is convenient to evaluate the patient’s airway humidification and whether the pipeline has the risk of pressure injury to the face.

It needs to establish an artificial airway when various non-invasive oxygen therapies cannot correct the hypoxia before the etiology of AHRF is clear [13]. We used the technology of electrical impedance tomography (EIT) to make it possible to perform bedside monitoring on the patient in the prone position, which could observe the changes in pulmonary ventilation and pulmonary blood perfusion dynamically in the prone position to judge the effect of prone position and to give guidance for clinical treatment [14]. The advantages of EIT are that it could reduce the risk of going out for examination, simple operation, and dynamic continuous assessment of lung conditions at the bedside. For the patient, it is a non-invasive operation, with no risk of ionization or radiation, and could provide a precise visualization intervention to improve the efficacy of the treatment.

Maintaining airway patency is the most basic and important treatment for any type of respiratory failure. In this case, the patient’s oxygen reserve was poor, and simple operations such as turning over or sputum suction caused a decrease in saturation. It was necessary to give 100% oxygen support before and after the operation. The color, quality, quantity, and taste of sputum were observed during each sputum suction. The sputum examination specimens were retained correctly according to laboratory examination requirements. Reporting to the doctor in time to adjust the treatment plan if there is a special condition. We assisted the patient to raise the head and chest by 30 ° ~ 45 ° during the supine position of the patient. Besides, we also implemented oral care every 6 h and maintained subglottic low negative pressure suctioning to prevent ventilator-associated pneumonia.

Pulmonary rehabilitation not only enhances the success rate of weaning and maximal inspiratory pressure in patients but also diminishes the incidence of complications such as ventilator-associated pneumonia and deep vein thrombosis [15]. Consequently, we undertook dynamic assessments of the patient’s oxygenation index, circulatory stability, ventilator weaning index, cough capability, and muscle strength classification. Furthermore, we implemented a stepwise pulmonary rehabilitation program tailored to improve the patient’s pulmonary function. Throughout the rehabilitation period, she was provided with psychological support and specialized health guidance to diminish uncertainties regarding her condition. Moreover, through physical contact, we fostered trust and treatment compliance, encouraging active participation in nursing care.

Limitations

The paramount limitation of this study is its focus on a single case, which introduces a high degree of variability in both treatment approach and clinical outcome, precluding generalized conclusions. Additionally, the follow-up duration was restricted to 1 month, leaving the patient’s longer-term prognosis unexplored. It remains uncertain whether subsequent drug or hormone therapy will ameliorate the patient’s ultimate clinical outcome. Currently, no unified treatment protocols exist, with prevailing methods encompassing surgical intervention and hormone therapy followed by regular monitoring. While some patients may become reliant on hormone therapy, others might experience disease progression post-treatment. Hence, it is crucial to remain vigilant about the potential worsening of the condition, despite the low probability of PBML exacerbation. We intend to maintain extended surveillance of this case.

Conclusion

In women of reproductive age presenting with hypoxemia lacking an overt cause but possessing a history of uterine, it is imperative to consider PBML as part of the differential diagnosis, integrating comprehensive historical and clinical examination data. In the described scenario, the patient experienced acute hypoxic respiratory failure attributed to PBML, Prior to a definitive diagnosis, strategies such as awake prone positioning, high-flow nasal, cannula oxygenation, electrical impedance tomography-guided airway management, and preliminary progressive pulmonary rehabilitation were employed to optimize oxygenation and prevent further pulmonary compromise. Prolonged monitoring and follow-up are essential for early detection of leiomyoma metastasis progression in PBML patients.