Liposarcoma

A 52-year-old woman presented to the emergency department complaining of a 2-week history of increasing right shoulder pain, paresthesias, and associated right supraclavicular neck swelling. The patient added that right supraclavicular neck fullness had been present for approximately 1 year, but she had attributed the fullness to weight gain because it was painless.

Examination revealed a 12 x 10-cm nontender soft-tissue mass with indistinct margins in the right supraclavicular fossa. Findings on fine-needle aspiration biopsy were consistent with a lipoma, but contrast-enhanced computed tomography (CT) of the neck identified a heterogenous 4 x 5-cm enhancing mass deep to an overlying lipomatous component that measured approximately 10 x 6 cm in the right lower jugular chain (figure 1). The results of a repeat fine-needle aspiration biopsy were unchanged.

[FIGURE 1 OMITTED]

The patient underwent an en bloc resection. Findings on gross intraoperative inspection were consistent with the CT results: a lipomatous mass over a distinctly different underlying tumor (figure 2). Final histology confirmed that the patient had a dedifferentiated liposarcoma.

[FIGURE 2 OMITTED]

Liposarcomas primarily affect adults (mean age: 50 yr), and there is a slight male preponderance. (1) They are mesenchymal tumors of lipogenic origin that arise from deep-seated connective-tissue spaces; most occur in the extremities and in the retroperitoneum. They account for approximately 15 to 20% of all soft-tissue sarcomas, a rate second only to that of malignant fibrous histiocytomas. (1) Liposarcomas are uncommon in the head and neck region, accounting for 3 to 5% of all cases. (2) They are more common in the neck than in the head. Almost all liposarcomas develop de novo. The degeneration of a primary lipoma into a liposarcoma is unlikely considering that liposarcomas are rarely reported to arise from immediate subcutaneous or submucosal sources, although they are similar to lipomas in terms of their indolent course and initial clinical presentation. Patients with a liposarcoma generally present with a painless mass that has caught their attention only after it has achieved significant size.

On gross pathologic examination, liposarcomas are typically well encapsulated, although microscopic examination can demonstrate infiltrative margins. Tumors are represented histologically by moderately sized malignant lipoblasts set in a myxoid background with a rich capillary network. There are five histologic subtypes: myxoid, well-differentiated, round-cell, pleomorphic, and dedifferentiated. Dedifferentiated liposarcomas have the appearance of well-differentiated liposarcomas except for areas of dedifferentiation with a nonlipoblastic sarcomatous component. Regional metastasis is rare. Distant metastasis via hematogenous spread is more common in the poorly differentiated forms; Zagars et al reported a rate of 37%. (3)

The treatment of choice is wide local excision. The efficacy of radiation as a primary or adjuvant therapy is debatable, but it has a definite role in treating partially resected or unresectable tumors. Chemotherapy may play a limited role in the myxoid type of tumor. Zagars et al reported a 10-year survival rate of 39% for poorly differentiated forms. (3)

The case described herein illustrates that clinical suspicion should be high for malignancy when atypical symptoms are associated with a seemingly benign lesion.

References

(1.) Golledge J, Fisher C, Rhys-Evans PH. Head and neck liposarcoma. Cancer 1995;76:1051-8.

(2.) Morse MA, Bossen E, D'Amico TA, et al. Myxoid liposarcoma of the supraclavicular fossa. Chest 2000;117:1518-20.

(3.) Zagars GK, Goswitz MS, Pollack A. Liposarcoma: Outcome and prognostic factors following conservation surgery and radiation therapy. Int J Radiat Oncol Biol Phys 1996;36:311-19.

Jason Hamilton, MD; Sofia Avitia, MD; Ryan Osborne, MD; Jimmy Brown, MD, DDS

From the Department of Otolaryngology, Charles R. Drew University of Medicine and Science (Dr. Hamilton, Dr. Avitia, Dr. Osborne, and Dr. Brown), and the Head and Neck Cancer Center, Cedars-Sinai Medical Center (Dr. Osborne), Los Angeles.

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