Unveiling spindle cell lipoma: a radiological case report

Spindle cell lipoma is a benign adipocytic tumour, commonly occuring in the subcutis of posterior neck, upper back and shoulder, particularly in middle aged males. It is often composed of relatively equal ratio of fat and spindle cells, yet either component may predominate. Because of its variable ratio, a spindle cell lipoma may mimic liposarcoma radiologically. This article aimed to describe the MRI characteristics that assist in diagnosing spindle cell lipoma. Case presentation: A 45-year-old female presented with a gradually progressive neck swelling along the posterior aspect over a period of 2 years. Physical examination revealed a firm, mobile, non-tender mass in the left suboccipital region. Radiographic imaging showed a well-defined heterogeneous, minimally enhancing soft tissue swelling with areas of macroscopic fat and multiple macrocalcifications in the left suboccipital region extending to the left parapharyngeal space, showing loss of fat plane with adjacent muscles. Differential diagnoses of soft tissue neoplasms such as atypical lipoma and low-grade liposarcoma were considered. Surgical excision confirmed a myxoid variant of spindle cell lipoma upon histopathological examination. Spindle cell lipomas, commonly found in the posterior neck, have varied imaging features that are not distinctive. Despite their non-specific nature, radiologists should recognize these features, as the tumor can be treated effectively with simple excision. When encountering a well-defined, complex fatty mass in the subcutaneous tissue of the posterior neck, consider a diagnostic possibility of spindle cell lipoma.