Spindle cell lipoma (SCL) is a relatively rare adipocytic neoplasm and is h
istologically characterized by a mixture of uniform spindle cells and matur
e fat cells. It occurs predominantly in male patients aged 45-65 years, and
in most cases it arises in the subcutaneous tissue of the neck or shoulder
. Although the neoplasm sometimes affects unusual sites, only three cases h
ave been reported in which the lesion was intramuscular. Here we present a
case of SCL arising in skeletal muscle; to our knowledge, the first report
in 10 years. the tumor occurred in the neck of a 50-year-old male patient.
Magnetic resonance imaging (MRI) revealed a lipomatous tumor within the rig
ht trapezius muscle. The tumor was localized beneath the fascia and was exc
ised completely at surgery. Histologically, the tumor was typical of a spin
dle cell lipoma with no evidence of malignancy. An immunohistochemical stud
y revealed all spindle cells were strongly positive for CD34. Differential
diagnosis is discussed with a review of the literature.