To describe MRI characteristics of onychomatricoma,
a rare and begnin fibroepithelial nail tumor.
The clinical appearence is longitudinal yellowish thickening of the nail plate with overcurvature but there is no specificity for the diagnosis.
Histopathological this tumor has two parts with a proximal matrix in the nail matrix and a distal part with multiple filamentous extensions in the nail plate.
Methods and Materials
The MRI of 24 patients with 26 onychomatricomas of fingers or toes were reviewed by 2 independent readers in this retrospective and monocentric study for patients between 1994-2015.
All patients included in the study had preoperative MRI on 1.5 or 3 Tesla and were then operated with histopathological diagnosis.
The MRI sequences are T1,
Ciss) and T1 gadolinium Fatsat.
MRI parameters were FOV=40mm,
size of slice 2-3mm,
matrix 256x256 or 192x192.
The MRI coil was a loop of 4 cm....
Two different types were separated and tested statistically according to their location: central on the midline (65%) or lateral (35%).
The size of the tumoral core is larger for lateral locations (3.6mm versus 2.3mm; p = 0.011).
The filamentous expansions of the lateral tumors are shorter (6.6mm versus 7.3mm; p =0.016) and more numerous (9.7 versus 7.6; p =0.025).
These filaments present more similar diameters in the central location (82% versus 33%; p =0.014).
Onychomatricomas present specific patterns with MRI.
MRI allows to separate two different types according to their location.
These characteristics allow to have the diagnosis of onychomatrocima without surgical histopathological proven.
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Lausanne university hospital,
Department of Radiology,
Switzerland. MD PhD J-L Drapé,
Paris university Cochin hospital,
Department of B Radiology,