Unusual Presentation of Lipofibromatosis-Like Neural Tumor in an Adult: A Case Report

Lipofibromatosis-like neural tumor (LPF-NT) is a rare variant of lipofibromatosis. Standard lipofibromatosis tumors show a predilection for the distal extremities of male children or young adults and are typically painless, slow-growing, subcutaneous or deep soft tissue masses. We present a case of a 50-year-old male with a slowly expanding, right foot mass. Physical examination revealed a painful, non-tender firm mass on the right medial foot. Magnetic imaging studies revealed a poorly defined soft tissue mass extending through subcutaneous tissue up to the dermis. Histologic examination revealed a spindle cell neoplasm. Immunohistochemistry showed co-expression of S100 protein, CD34 and TRK. In addition, the lesion was found to be positive for the LMNA-NTRK1 fusion by next-generation sequencing. These findings were supportive of a diagnosis of LPF-NT. At 3-month post-excision, the patient had no pain and repeat imaging indicated no evidence of tumor. The authors recommended including LPF-NT in the differential diagnosis of masses or lesions that are fibro-fatty tumors.