An Unusual Case of Intravenous Leiomyomatosis Involving the Right Atrium
Intravenous leiomyomatosis (IVL) is a rare and unusual condition characterized by the growth of benign smooth muscle tumors within the venous system, often extending from the pelvic veins into the inferior vena cava and, in some cases, reaching the right atrium of the heart. This condition predominantly affects women, typically between the ages of 33 and 54, with an average age of 44. Most patients have a history of uterine fibroids or hysterectomy, which suggests a potential connection between IVL and uterine smooth muscle cells. The case of a 48-year-old Chinese woman with IVL involving the right atrium provides a comprehensive example of the clinical presentation, diagnostic challenges, and treatment strategies associated with this rare disease.
Clinical Presentation and Initial Evaluation
The patient, a 48-year-old woman, presented with a three-month history of chest distress, shortness of breath, and amaurosis fugax (transient vision loss). These symptoms had progressively worsened over the preceding week. During a physical examination, a diastolic rumbling murmur was detected at the third and fourth intercostal spaces along the left sternal border while the patient was seated. Her vital signs were stable, and initial laboratory tests revealed no abnormalities.
Cardiac ultrasound, performed using a GE VIVID E9 Color Doppler Ultrasonic Diagnosis Apparatus, identified a neoplasm in the inferior vena cava and right atrium. The mass within the right atrium measured 78 mm by 38 mm. Gynecologic ultrasonography, conducted with a Siemens ACUSON S2000, revealed a large cyst-solid mass in the pelvic cavity, measuring 132 mm by 131 mm by 98 mm. Magnetic resonance imaging (MRI), performed with a Siemens Skyra 3.0 T scanner, confirmed the presence of soft tissue signals in the internal and external iliac veins, the right common iliac vein, and the inferior vena cava, with extension into the right atrium. Additionally, a substantial soft tissue mass was observed in the pelvic cavity.
Surgical Intervention and Pathological Findings
The patient underwent a two-stage surgical procedure to address the extensive tumor involvement. The first stage involved cardiac and vascular surgery, performed under general anesthesia with extracorporeal circulation. During this procedure, a mass measuring 6 cm by 6 cm by 3 cm was resected from the right atrium. Histological examination of the resected tissue, using hematoxylin and eosin staining, revealed fusiform smooth muscle cells arranged in bundles, along with vascular hyaline degeneration within the tumor. Immunohistochemical staining further characterized the tumor cells, showing positive reactions for Desmin, vimentin, smooth muscle actin (SMA), CD31, CD68, and CD34, while S-100, cytokeratin pan (CKP), and myoD1 were negative. The Ki-67 proliferation index was less than 10%. These findings supported a diagnosis of angioleiomyoma.
In the second stage of the operation, the patient underwent a panhysterectomy, bilateral salpingo-oophorectomy, and myomectomy of the inferior vena cava. Two masses, each 30 cm in length, were removed from the inferior vena cava. Pathological examination of these masses revealed spindle-shaped tumor cells arranged in knit-like and bunch-like formations, with rare mitotic figures. Immunohistochemical staining of these tissues showed strong positivity for estrogen receptor (ER) and progesterone receptor (PR), with 75% expression for both. The Ki-67 index was 5%, and the tumor cells were strongly positive for SMA and Desmin, while S-100 and p53 were negative. These findings confirmed the diagnosis of intravenous leiomyomatosis.
Discussion and Pathogenesis
IVL is a rare condition with a poorly understood pathogenesis. The most widely accepted theory suggests that IVL arises from the local extension of myometrial smooth muscle cells into adjacent venous channels within the pelvic cavity. Less commonly, IVL is believed to originate from smooth muscle cells within the vessel walls. The presence of ER and PR in the tumor cells supports the hypothesis that hormonal factors may play a role in the development and progression of IVL. This is further supported by case reports of IVL patients with elevated estradiol levels and strong ER expression in tumor tissues.
The histological and immunohistochemical findings in this case are consistent with previous reports. The tumor cells exhibited features typical of smooth muscle differentiation, including positive staining for SMA and Desmin. The absence of S-100 and CKP staining ruled out neural and epithelial origins, respectively. The low Ki-67 index indicated a low proliferative activity, consistent with the benign nature of the tumor.
Treatment and Prognosis
Surgical resection remains the primary treatment for IVL, as demonstrated in this case. The two-stage surgical approach was necessary due to the extensive involvement of the venous system and the right atrium. The first stage addressed the cardiac involvement, while the second stage focused on removing the pelvic and venous components of the tumor. Complete resection is crucial to prevent recurrence, which occurs in approximately 30% of cases.
Hormonal therapy, including antiestrogenic drugs such as tamoxifen and gonadotropin-releasing hormone agonists (GnRHa), has been used in some cases, although its efficacy remains uncertain. In this case, the patient did not receive hormonal therapy, and no tumor recurrence was observed during the nine-month follow-up period.
Conclusion
Intravenous leiomyomatosis is a rare and diagnostically challenging condition that requires a high index of suspicion, particularly in women with a history of uterine fibroids or hysterectomy. Early detection and timely surgical intervention are critical for successful treatment. The case presented here highlights the importance of a multidisciplinary approach, involving cardiology, gynecology, and pathology, to achieve optimal outcomes. Given the high recurrence rate, long-term follow-up is essential to monitor for potential tumor regrowth.
This case also underscores the need for further research into the pathogenesis of IVL, particularly the role of hormonal factors, to develop more effective treatment strategies. The strong expression of ER and PR in the tumor cells suggests that hormonal therapies may have a role in the management of this condition, although their efficacy remains to be established.
In conclusion, intravenous leiomyomatosis involving the right atrium is a rare but serious condition that requires prompt diagnosis and comprehensive surgical management. The case presented here provides valuable insights into the clinical presentation, diagnostic challenges, and treatment strategies for this unusual disease.
doi.org/10.1097/CM9.0000000000000082
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