Learning objectives
Definition of Hoffa's fat pad (HFP)
Definition of perivascular epithelioid cell tumor (PEComa)
Diagnostic imaging choice for HFP tumors
Background
The infrapatellar Hoffa’s fat pad (HFP) is an intracapsular,
but extrasynovial,
constant structure in the knee,
which may play a number of roles in knee joint function and pathology.
It is commonly injured and pathology of the fat pad is a common cause of anterior knee pain.
Abnormalities within HFP most commonly are the consequences of trauma and degeneration,
but inflammatory and neoplastic diseases can arise in the fat pad.
A variety of intrinsic and extrinsic tumors and tumorlike conditions may affect the infrapatellar HFP...
Imaging findings OR Procedure Details
MRI is the choice of imaging for HFP tumours.
MRI offers superior tissue contrast and is more accurate than computed tomography (CT) in defining the size andextent of a soft tissue lesion.
We recommend a plain knee radiograph as an initial imaging study,
as findings such as soft tissue mass (haemangioma) or fat pad calcification(chondroma,
synovial sarcoma) may help to suspect a tumour pathology and consider the possibility of malignancy (Figure 1).
Our patient is 24 y/o,
male patient with anterior left knee pain.
In...
Conclusion
HFP tumours are an uncommon and rarely diagnosed group of lesions that can be misinterpreted as any knee pathology.
Increased awareness is required to diagnose this clinical condition early and to start the appropriate treatment in order to avoid morbidity.
Although the majority of HFP tumours are benign,
malignant tumours should be considered.
References
Helpert C,
Davis AM,
Evans M,
Grimer RJ.
"Differential diagnosis of tumours and tumour like conditions of infrapatellar fat pad: Pictoral review with emphesis on MRI." Eur Radiol 2004;14:2337-23246.
Ghate SD,
Deokar BN,
Samant AV,
Kale SP.
"Tumor like swellings arising from Hoffa's fat pad:a report of three patients." Ind.
J.
Orthop 2012;46(3):364-368.
Folpe AL,
Mentzel T,
Lehr HA,
Fisher C,
Balzer BL,
Weiss SW.
"Perivascular epithelioid cell neoplasms of soft tissue and gynecologic origin: a clinicopathological study of 26 cases and review of the...
Personal Information
M.Gök; Adnan Menderes University Hospital,
Department of Radiology - Aydin/TR.
F.T.
Özgezmez; Adnan Menderes University Hospital,
Department of Orthopedic - Aydin/TR.
C.
Tataroglu; Adnan Menderes University Hospital,
Department of Pathology - Aydin/TR.