| Abstract|| |
Primary pericardial neoplasms account for 6.7–12.8% of all primary tumors arising in the cardiac region. Pericardial tumors are most likely to be metastatic and are an extension of the primary tumors from the surrounding structures. Sarcomas of the pericardium are rare. Myxoid liposarcoma (ML) represents about 5% of all the soft-tissue sarcomas in adults. They are usually located in the deep soft tissues of the extremities. There have been less than 20 cases of pericardial liposarcomas reported on PubMed since 1973. Here, we present a rare case of primary giant pericardial myxoid liposarcoma (ML) in a 46-year-old female diagnosed on frozen section and later was confirmed histopathologically.
Keywords: Large, liposarcoma, pericardial
|How to cite this URL:|
Sinai Khandeparkar SG, Kulkarni MM, Mishra P, Mushir Patel AZ. A rare case of primary giant myxoid liposarcoma of the pericardium. Indian J Pathol Microbiol [Epub ahead of print] [cited 2023 Mar 21]. Available from: https://www.ijpmonline.org/preprintarticle.asp?id=344190
| Introduction|| |
Primary pericardial neoplasms account for 6.7–12.8% of all primary tumors arising in the cardiac region. Pericardial tumors are most likely to be metastatic and are an extension of the primary tumors from the surrounding structures. The most common benign pericardial mass is a pericardial cyst followed by lipoma. Mesothelioma is the most common primary pericardial malignancy. Other primary malignant neoplasms include a wide variety of sarcomas as well as lymphomas.
The most common pericardial sarcomas are synovial sarcoma, angiosarcoma, and undifferentiated pleomorphic sarcoma. ML, the second most common subtype of liposarcomas, accounts for 15–20% of the liposarcomas and represents about 5% of all the soft-tissue sarcomas in adults. ML peaks in the fourth and fifth decades and are usually located in the deep soft tissues of the extremities. There have been less than 20 cases of pericardial liposarcomas reported on PubMed since 1973. Here, we present a rare case of primary giant pericardial ML in a 46-year-old female diagnosed on a frozen section and later confirmed histopathologically.
| Case Report|| |
A 46-year-old female presented to the surgery-outpatient department with chest pain and breathlessness on exertion for 1 month. There was decreased appetite and loss of weight noticed by the patient for the same duration. The respiratory system examination showed decreased air entry on the left side. There were no other contributing systemic examination findings. Plain computed tomography (CT) of the thorax showed a large cystic mass in the left upper and mid-lobe region [Figure 1]a. It showed septi and calcifications within. It measured approximately 11.8 cm × 11.1 cm in size causing mass effect over the mediastinum resulting in the shift of the mediastinal structures toward the right. There was a mild left-sided pleural effusion with basal sub-segmental atelectatic changes. The mediastinal fat planes were well-maintained. The cardiac size and configuration were within the normal limit. The trachea and bronchi were well seen and appeared normal. The possibility of differential diagnosis of the hydatid cyst and cystic neoplastic mass lesion was offered. Intraoperatively, the left posterior lateral thoracotomy incision was given in the fourth intercostal space. There was evidence of a large cystic tumor measuring approximately 20 cm × 20 cm in size compressing the lung and mediastinum. The tumor appeared cystic and was filled with myxoid material. The cyst wall was adhered to the pericardium and aorta. The tumor appeared to arise from the pericardium. The contents of the cyst were received for the frozen section. It showed a single, soft, gelatinous lobulated mass measuring 9.5 cm × 7.5 cm × 4 cm [Figure 2]. Extensive myxoid material, numerous delicate vascular channels having chicken wire configuration together with occasional lipoblast favored the diagnosis of myxoid lipogenic tumor favoring ML. The tissue received for histopathological examination contained multiple, yellowish, soft gelatinous tissue mass all aggregating to 20 cm [Figure 1]b. The microscopic examination showed the tumor composed of an abundant myxoid matrix with prominent plexiform and arborizing delicate capillaries giving rise to chicken wire configuration. Lipoblasts were seen amidst this having characteristic round to oval scalloped nucleus at places showing hyperchromasia and pleomorphism and multivacuolated cytoplasm. Focally (less than 5%) cellular round cell areas were seen. A few abnormal mitotic figures, areas of necrosis, and hyalinization were noted [Figure 2]. The diagnosis of ML was offered. Immunohistochemistry (IHC) was not done in this case due to the characteristic morphology of the tumor. Ultrasonography of the abdomen and pelvis was unremarkable. Postoperatively, the patient received chemotherapy and is disease-free on follow-up for 3 months.
|Figure 1: (a) Plain computed tomography (CT) image of the thorax showing a large cystic mass in the left upper and mid-lobe region measuring 11.8 cm × 11.1 cm in size causing mass effect over the mediastinum resulting in the shift of the mediastinal structures toward the right and left lung posteriorly. (b) Gross photograph of the myxoid liposarcoma showing multiple, yellowish, soft gelatinous tissue mass all aggregating to 20 cm|
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|Figure 2: Photomicrograph of the frozen section of the myxoid liposarcoma showing characteristic (a) chicken wire configuration of the blood vessels (a, inset) myxoid areas, (b) lipoblast (yellow circle), Photomicrograph of histopathological section of the myxoid liposarcoma showing (c) myxoid areas and chicken wire configuration of the blood vessels, (d) round cell areas with mitotic figure (red circle) and lipoblast (yellow circle)|
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| Discussion|| |
ML is a slow-growing tumor that is often large at presentation as seen in the present case where the size of the tumor was about 20 cm in diameter at the time of excision. Their large size and invasive nature limit complete surgical excision. At imaging, pericardial liposarcomas appear similar to liposarcomas that occur elsewhere in the body. On CT images, pericardial liposarcomas appear as predominantly fatty to heterogeneous masses with areas of low-attenuation values. In the present case, it was predominantly a cystic, loculated, and encapsulated mass giving possible differentials of hydatid cyst and cystic neoplasm. Magnetic resonance imaging (MRI) also depicts their fatty nature and is useful for assessing the degree of invasion. Due to financial constraints, the MRI could not be done in this case.
These tumors are of particular concern due to the fact that overt signs and symptoms occur rather late in the course, precluding effective tumor eradication. Pericardial tumors often cause symptoms related to malignant pericardial effusion. The presenting symptoms are cough, dyspnea, chest pain, and palpitations, which are a result of the mass effect of the tumor on the cardiac chambers. In this case, the patient had breathlessness and pain in the chest for the past 1 month.
The frozen section is a good diagnostic aid in the cases where guided fine-needle aspiration cytology is not performed as in this case. the giant size of 20 cm, extensive myxoid material, numerous delicate vascular channels having chicken wire configuration together with occasional lipoblast favored the diagnosis of ML in the present case on the frozen section which was later confirmed on histopathology. Besides the characteristic features of ML, histopathology showed less than 5% of the cellular round cell areas. In a large tumor, such as in this case, it needs extensive sampling to rule out the possibility of such foci which can impact the prognosis and treatment strategies.
The differential diagnoses to be considered in a large tumor with extensive myxoid degeneration in the thoracic region include myxoma (common primary cardiac tumor with stellate myxoma cells and glandular component), myxoid lipoma (has mature adipocytes), myxofibrosarcoma (located mainly in the extremities with pleomorphic spindle cells, pseudolipoblast, curvilinear vessels, high-grade tumor areas composed of spindly cells, necrosis, mitotic figures, and multinucleated giant cells, no specific IHC stain) and low-grade fibromyxoid sarcoma (biphasic with more fibrous and less myxoid areas, thicker-walled curvilinear capillary-sized blood vessels, a translocation involving the FUS gene, MUC4 highly sensitive, and specific stain). The analysis of the vascular pattern, degree of nuclear atypia, and staining characteristics of the matrix could aid in this distinction. IHC was not performed in this case due to the characteristic histomorphology of the tumor cells.
It has been reported that the tumor site, percentage of round cell component, necrosis, mitosis, MIB-1 labeling index, and tumor grade had a significant impact on the overall survival in the ML cases. There was the presence of focal areas of necrosis and abnormal mitotic figures (2/10HPF in the round cell areas) in the present case.
Another feature that distinguishes ML from the other liposarcomas is the tendency to metastasize in unusual regions, more precisely where fat tissue is present as the trunk, extremities, bone, retroperitoneal site, chest wall, pleura, and pericardium. As the metastasis are not uniformly FDG (fluorodeoxyglucose) avid, FDG positron emission tomography (PET) has a low sensitivity for the detection of metastatic disease.
Surgical excision with or without radiation therapy is the treatment of choice in the localized ML. Chemotherapy is generally reserved for patients with high-risk diseases such as a high-grade, deep-seated tumor, tumor size >5cm, and positive surgical margins. Post-surgical excision, the patient was given chemotherapy. She is disease-free for 3 months. Long-term follow-up of these tumors is important because of the high recurrence rate. The rate for survival, metastasis, and recurrence specific for primary pericardial ML is not available in the literature.
Our experience with the present case puts on record the rare case of giant ML of an unusual site as pericardium diagnosed on the frozen section.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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Siddhi Gaurish Sinai Khandeparkar,
Address: E-517, The Island, Wakad, Pune - 411 057, Maharashtra
Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2]