Hoffa’s fat pad tumours: What do we know about them?

Abstract

Purpose We report on a group of patients with tumours in the Hoffa's fat pad (HFP), their clinical presentation, histological type and treatment, including two synovial sarcomas with their clinical follow-up, which have not been described previously in the literature. Methods We performed a retrospective review of our prospectively collected database of 25 cases of HFP tumours with at least six months follow-up. Results The gender, age at presentation (over and under 16 years of age), clinical features, history of trauma, treatment chosen, and complications were recorded. The mean age of the patients was 32 years (three to 47). Six patients were under 16 years old. Pain was the most common symptom, present in 92 % (n =23/25). The final diagnoses included 23 (92 %) benign tumours and two (8 %) malignant tumours. The most common benign tumour was pigmented villonodular synovitis (PVNS) (48 % n =12). The two malignant tumours were synovial sarcomas and both presented in patients under 16 years old. Conclusions Hoffa's fat pad tumours are an uncommon and rarely diagnosed group of lesions that can be misinterpreted as any knee pathology. Although the majority of HFP tumours are benign, malignant tumours should be considered in the differential diagnosis for the paediatric population.

Calcified or ossified benign soft tissue lesions that may simulate malignancy

“…The exact frequency of ossification in Hoffa’s disease is currently unknown. Synovial sarcoma can arise in Hoffa’s fat pad [32] and could be included in the differential diagnosis, along with venous malformation. However, ossification is an unusual phenomenon in both synovial sarcoma and venous malformation.…”

“…Positron emission tomography is not useful to differentiate tumoral calcinosis from malignancy because tumoral calcinosis can demonstrate avid FDG uptake [35–37]. Differential diagnostic considerations include, amongst others, calcinosis associated with chronic renal failure and soft tissue sarcoma [32]. Careful review of clinical history, laboratory test results, location, and imaging appearance helps to differentiate tumoral calcinosis from these entities.…”

Schwannoma: A Rare Hoffa's Fat Pad Tumor

“…4 In 2013, Albergo et al presented 25 patients who were most commonly diagnosed with pigmented villonodular synovitis and hemangioma; two malignant tumors were reported, and none of those were diagnosed with schwannoma. 5 Despite its rarity, schwannoma should be considered in the differential diagnosis.…”

Fat Chance for Hidden Lesions: Pictorial Review of Hoffa's Fat Pad Lesions

“…The fluid suppression sequences help document bone marrow edema and erosions. 16 Differential considerations of synovial sarcoma, 17 hemosiderotic synovitis, hemophilic arthropathies, and rarely malignant fibrous histiocytoma must be considered. 18…”