Hybrid myxoinflammatory fibroblastic sarcoma/hemosiderotic fibrolipomatous tumor of the ankle following repeated trauma

To the Editor: Myxoinflammatory fibroblastic sarcoma (MIFS) is a low grade sarcoma with predilection for the distal portions of the extremities, first described in 1998 under different names by three independent groups of authors, as ‘inflammatory myxoid tumor of the soft parts with bizarre giant cells’, ‘inflammatory myxohyaline tumor of distal extremities with virocyte or ReedSternberg-like cells’ and ‘acral myxoinflammatory fibroblastic sarcoma’. As the tumor is not entirely restricted to acral sites, the term ‘acral’ was withdrawn from the latter to reach a consensus name. MIFS is characterized by proliferation of low grade atypical spindle cells embedded in myxoid and inflammatory stroma with a proportion of larger cells resembling Reed-Sternberg cells and showing characteristic intranuclear virocyte-like inclusions. To date, there have been very few reports of high grade transformation and metastasis. In 2000, Marshall-Taylor and Fanburg-Smith first reported a distinctive soft tissue proliferation characterized by lipomatous/hemosiderotic spindle cell histology and predilection for the ankle of female patients. ‘Hemosiderotic fibrohistiocytic lipomatous lesion’ was the original name, which was later abbreviated to ‘hemosiderotic fibrolipomatous tumor’ (HFLT). More recently, several studies have demonstrated a consistent t(1;10)(p22;q24) translocation in both tumors, showing evidence for a common origin. Further findings from the few recently reported hybrid HFLT/MIFS cases give evidence that HFLT and MIFS could represent different levels of tumor progression within the same entity. A 57-year-old woman was admitted for treatment of a large soft tissue tumor surrounding the right ankle and extending distally along the foot arch (Fig. 1a). Clinical history showed multiple repeated injuries in the ankle and foot area, which started 40 years prior, when the patient suffered a right ankle fracture. Twelve years later, the patient developed frostbite in the same area. A year later, a tractor spreader drove across the same foot. In 1996, 23 years after the incipient injury, lymphedema of the right foot started to develop. Two years later, the patient spilt boiling water across the foot. In a few days, the patient fell and broke the ankle again. Six years later, the foot was traumatized in a traffic accident. It was only in 2006 that the patient was admitted for treatment of lymphedema. Two tumors measuring 6 × 5 cm and 3 × 5 cm, respectively, were excised from the ankle and foot region and confirmed as lipomas by the pathologist at an external institution. In 2013, the patient underwent another biopsy in our institution because of tumor recurrence, which raised suspicion for high grade liposarcoma. Radiography revealed a multinodular tumor untreatable by local excision, measuring up to 15 cm. PET-CT scan confirmed the finding, and also revealed increased fluorodeoxyglucose (FDG) uptake in an enlarged right inguinal lymph node. The patient underwent transtibial amputation and biopsy of the enlarged lymph node. Six months after amputation, the patient is without signs of recurrence.