Aberrant muscle syndrome: Hypertrophy of the hand and arm due to aberrant muscles with or without hypertrophy of the muscles

Abstract

Five patients were reported in our congenital anomaly registry who had six hands in total with muscular hyperplasia, aberrant muscles, ulnar drift of the fingers in the metacarpophalangeal (MP) joints, flexion contractures of the MP joints, and enlargement of the metacarpal spaces. Thirty patients with unilateral involvement of this condition have been reported previously. We reviewed these cases and found that the condition varied in severity and that it was reported using different names. However, this condition seems different from true macrodactyly and multiple camptodactyly, including windblown hand, and seems to be an isolated entity of congenital upper limb anomaly. The authors recommend 'aberrant muscle syndrome' or 'accessory muscle syndrome' as a diagnostic name, because this seems to be the most common pathological finding in this condition.

Early activating somatic PIK3CA mutations promote ectopic muscle development and upper limb overgrowth

“…In three operated patients, aberrant accessory muscles were detected but none of these cases were confirmed by molecular analysis. Aberrant accessory muscles have also been reported in other surgically treated patients with upper limb muscle hypertrophy and in some cases of carpal tunnel syndrome, but no genetic analysis of aberrant muscles have been performed to rule out somatic mosaic PIK3CA mutations. To the best of our knowledge, there are three patients previously described with isolated upper limb muscle overgrowth and with a confirmed PIK3CA mutation .…”

“…The terminology “aberrant muscle syndrome” or “accessory muscle syndrome” has been suggested to describe patients with “hypertrophy of the hand and arm because of aberrant muscles with or without hypertrophy of the muscles.” It has been proposed that an increased number of neuromuscular junctions and a change in the muscle‐tendon ratio is involved in muscle hypertrophy development . The etiology remains still undetermined but it has recently been reported that isolated congenital muscular upper limb overgrowth can be related to somatic mosaic PIK3CA mutations …”

Upper limb congenital muscular hypertrophy and aberrant muscle syndrome in children

“…Several terminologies have been used to describe the congenital muscular hypertrophy condition (De Smet and Fryns, 1994; Lanz et al., 1994; Pillukat and Lanz, 2004; Stark et al., 1979; Tanabe et al., 1997). According to Ogino et al. (2010), the enlargement of the hand is related to both aberrant and hypertrophic muscles.…”

Congenital Bimelic Hypertrophy of the Hands

“…So far, only 17 cases have been described in the German and English medical literature. The condition varies in severity and has been reported under different names, such as aberrant muscle syndrome and congenital monomelic hypertrophy [ 2 , 3 , 4 , 5 , 6 , 7 , 8 ]. On MRI and ultrasound, muscle tissue is characterized by normal signal intensity and architecture [ 4 ].…”

“…Cases of bilateral involvement have been described four times so far (table 1 ) [ 1 , 6 , 9 , 10 ]. In the 3 adult cases, only the first dorsal interosseus muscles were involved, whereas our patient had diffuse involvement of all hand muscles, with prominence of the abductor pollicis muscles.…”