A rare case of myxoid liposarcoma of the adult foot diagnosed using fine needle aspiration cytology (FNAC)

Abstract

Shoko Kure,1 Wei-Xia Peng,1 Mitsuhiro Kudo,1 Miyuki Matsubara,2 Takashi Tsunoda,3 Zenya Naito1,21Department of Integrated Diagnostic Pathology, Nippon Medical School, 2Department of Pathology, Nippon Medical School Hospital, 3Department of Orthopedics, Nippon Medical School Department of Orthopedics, Nippon Medical School, Tokyo, JapanAbstract: Liposarcoma is categorized as a soft tissue sarcoma that most commonly appears in the lower extremities during adulthood, but rarely in the feet. We present a rare case of a primary myxoid liposarcoma in the foot of a 63-year-old man that was diagnosed by fine needle aspiration cytology (FNAC). The patient presented to our hospital with a 10-year history of a slow-growing mass on the left lateral ankle. On physical examination, the 60 mm ×60 mm mass, was found to be soft and elastic, causing poor mobility without pain. Magnetic resonance imaging of the mass revealed high signal intensity on T1-weighted images and heterogeneously high signal intensity on T2-weighted images without fat suppression. As a result of the physical examination and imaging, the mass was suspected to be a lipoma or ganglion cyst. However, the FNAC procedure revealed atypical small, round, short spindle cells, or foamy cells with a myxoid background, suggesting myxoid liposarcoma. Histology using an open biopsy showed a proliferation of atypical spindle and asteroid cells with a few foamy lipoblasts in a capillary-rich and myxoid background. The atypical lipoblasts were slightly positive for S-100. These findings were consistent with myxoid liposarcoma. The patient was treated with a resection of the mass. Liposarcoma is considered to be the second most common soft-tissue sarcoma. It usually involves the lower extremities, particularly the thigh, and is very rare in the adult foot. Our case was a rare occurrence of myxoid liposarcoma of the foot diagnosed preoperatively using FNAC.Keywords: myxoid liposarcoma, foot, fine needle aspiration cytology (FNAC), adult