The “wrench-head” appearance of thigh muscle CT in infantile facioscapulohumeral muscular dystrophy

Excerpt

Recently, we identify a specific pattern of thigh muscle involvements in two patients aged 15 years and 28 years, respectively, with a severely infantile variant of facioscapulohumeral muscular dystrophy (FSHD). Genetically, both of them obtain a very short EcoRI fragment (13 kb and 11 kb, respectively). Clinically, they had initial FSHD-associated symptoms (facial weakness) onset at 3 years and 3.5 years of age, respectively. Both of them lost ambulatory ability before 20 years of age and presented with several extramuscular manifestations, including hearing loss and retinal abnormalities. In their muscle CT of thighs, selective degeneration of bilateral rectus femoris with sparing other parts of anterior thigh muscles, accompanying dramatic wasting of hamstring muscles, depicted a novel “wrench-head” appearance (Fig. 1). The CT findings of lower extremities correlated with rapid clinical deterioration as these patients lost their ambulatory ability before the second decades. Compared to other FSHD patients in our database, this peculiar muscle CT finding has never presented so early and dramatically in elder, classical FSHD patients.

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