Liposarcoma
Key Points
Liposarcoma (LPS) is the most common soft tissue sarcoma in adults
In the periorbital region, liposarcomas may present in the orbit or on the eyelid
They originate from primitive mesenchymal cells rather than from mature fat cells and usually develop in deep structures
They usually present as a firm, mobile, nodular to lobulated, painless mass with well-defined to indistinct margins
Complete wide surgical excision is considered the treatment of choice
Incomplete surgical excision is associated with a high local recurrence rate of 80%
Radiotherapy is ineffective, and results of chemotherapy are inconsistent
The histologic subtype is an important prognostic indicator. Well-differentiated and myxoid LPS are low-grade lesions with 5-year survival rates of 83% to 100%; pleomorphic LPS is more aggressive, with a 20% to 60% 5-year survival rate
Liposarcoma (LPS) is a malignancy first described by Virchow in 1857.1 It is the most common soft tissue sarcoma, accounting for 15% to 25% of all soft tissue malignancies in adults.2 Most are located in the lower extremities, the retroperitoneum, and the mesenteric region of middle-aged individuals. LPS is uncommon in the head and neck area where it represents only approximately 1% of all sarcomas.3,4,5 In the head and neck, liposarcomas have been reported in the neck, larynx, lip, oral cavity, cheek, larynx, thyroid gland, tongue, parapharyngeal region, temporal and frontoparietal regions, eyelid, and orbit.6,7,8,9
According to the 2020 World Health Organization classification scheme, there are five subtypes of liposarcoma: atypical lipomatous tumor/well-differentiated liposarcoma, dedifferentiated liposarcoma (DDLPS), myxoid liposarcoma, pleomorphic liposarcoma, and the exceptionally rare myxoid pleomorphic liposarcoma.10 Goldblum, Folpe, and Weiss2 advocated classifying liposarcomas into three large groups: well-differentiated/dedifferentiated (54%-64%; including spindle cell, atypical, inflammatory, and sclerosing subtypes), myxoid (25%-35%), and pleomorphic (8%-10%).2,8,10,11,12 Generally, the well-differentiated and myxoid types behave as low-grade tumors and are more likely to occur in the head and neck.13 The well-differentiated variety can undergo dedifferentiation, where it behaves more aggressively. The pleomorphic and round cell types demonstrate a more aggressive, high-grade behavior.11
Most liposarcomas are seen in adults, with a median age of 57 years, a predominance in males of about 76.5%, and 82% occur in white individuals.13 The well-differentiated subtype is reported to occur in slightly older individuals and myxoid and pleomorphic subtypes in younger patients.14
In the periorbital region, liposarcomas may present in the orbit or on the eyelid. Primary orbital tumors have been reported in fewer than 50 cases, with the most common types being myxoid and well-differentiated subtypes.15,16 Occasionally, orbital LPS can present initially as an eyelid mass.9 Primary liposarcoma of the eyelid, on the other hand, is extremely rare, with only three cases reported in the literature.17,18,19
Etiology and Pathogenesis
Liposarcoma is thought to originate from primitive mesenchymal cells rather than from mature fat cells, and it usually develops in deep structures, whereas benign lipomas generally arise within subcutaneous and submucous tissues.
The classification scheme of LPS reflects distinct chromosomal aberrations in each category. About 90% of well-differentiated and dedifferentiated lesions have amplified chromosomal sequences of the 12q13-15 region, which carry the oncogenes MDM2, CDK4, and HMGA2.20 In myxoid liposarcomas, 95% carry a translocation of t(12;16) (q13;p11) involving the DDIT3 (CHOP) and FUS genes.21,22 Pleomorphic LPSs are high-grade malignancies that show complex karyotypes often with the loss of the tumor suppressor genes P53 and Rb.20
Clinical Presentation
LPSs are slow-growing tumors. On clinical examination, they usually present as a firm, mobile, nodular to lobulated, painless mass with well-defined to indistinct margins. Lesions can be present for months to many years, and they are usually not associated with regional lymphadenopathy. In the head and neck, they are most commonly located in the subcutaneous connective tissue of the face, neck, and scalp, with relatively rare occurrences in the oral cavity and salivary glands.13
LPS of the eyelid is exceedingly rare and presents as a soft to firm, mobile subcutaneous mass (Figure 134.1). Only three cases in the eyelid have been reported.17,18,19 One was a 67-year-old Chinese man who presented with a left lower
eyelid mass that had been present for 11 years. After a long period of slow growth, the lesion rapidly enlarged over 2 months.17 On presentation, the subcutaneous mass was mobile, 60 mm in diameter with indistinct margins, and was initially diagnosed as a lipoma or neurofibroma. On histopathology, it was diagnosed as a well-differentiated LPS. Another case was a 25-year-old man, with a slowly growing left eyelid mass for 2 years.18 It also was a well-differentiated LPS. The third case was an 11-year-old girl with a small left upper lid round cell LPS.19 Despite multimodal therapy, the tumor recurred, and the child died from widespread metastases to the central nervous system and soft tissues.
eyelid mass that had been present for 11 years. After a long period of slow growth, the lesion rapidly enlarged over 2 months.17 On presentation, the subcutaneous mass was mobile, 60 mm in diameter with indistinct margins, and was initially diagnosed as a lipoma or neurofibroma. On histopathology, it was diagnosed as a well-differentiated LPS. Another case was a 25-year-old man, with a slowly growing left eyelid mass for 2 years.18 It also was a well-differentiated LPS. The third case was an 11-year-old girl with a small left upper lid round cell LPS.19 Despite multimodal therapy, the tumor recurred, and the child died from widespread metastases to the central nervous system and soft tissues.
 FIGURE 134.1 A large, lobular subcutaneous liposarcoma of the lower eyelid. (Courtesy of Dr. Santha Amrith.) |
Differential Diagnosis
Clinically liposarcoma can be misdiagnosed as a cyst or benign soft tissue neoplasms, such as lipoma and neurofibroma, as well as other malignant tumors including dermatofibrosarcoma protuberans, low-grade malignant peripheral nerve sheath tumor, low-grade sarcoma, and low-grade myxofibrosarcoma.
Treatment
The treatment of liposarcoma is related to the tumor histologic type and grade.4 Well-differentiated LPSs tend to recur locally (45%) but do not metastasize without dedifferentiation.23 Myxoid and dedifferentiated LPSs rarely metastasize, but they are more locally invasive and show a greater tendency to recur compared with the well-differentiated type. Pleomorphic and round cell liposarcomas are more aggressive with higher recurrence rates (70%-100%) and a 5-year survival rate of 50% to 60%.4,24 The anatomic location also influences potential treatment options, and for head and neck LPS, the survival rate is better than for those at most other locations.4
Complete wide surgical excision is considered the treatment of choice for LPS. In a review of 22 cases with sufficient documentation, McCulloch et al24 reported that, with incomplete surgical excision, the local recurrence was 80% at 2 years, compared with a rate of 17% at 5 years with complete excision. Local recurrence may occur many years after surgical excision so that long-term follow-up is necessary.25
Radiotherapy does not appear to be very effective in the management of LPS,24 and its value has been controversial. Some studies reported no benefit with radiotherapy added to surgery,26 whereas others reported reduced recurrence and improved survival with radiotherapy combined with surgery.23,27 Radiotherapy is especially recommended for high-grade tumors, surgical resections with positive margins, larger tumors, and sites where complete surgical excision may not be possible.5 More recently, several authors have proposed that postoperative adjuvant radiation might delay or prevent local recurrence.14,28,29
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