Hydrops Fetalis Associated with Congenital Cytoplasmic Body Myopathy

We report a case of congenital cytoplasmic body myopathy which manifested as fetal hydrops in utero and was subsequently confirmed by muscle biopsy after birth. It is speculated that fetal hydrops is one of the clinical features associated with congenital cytoplasmic body myopathy, which is, to our knowledge, reported here for the first time.


Introduction
Cytoplasmic body myopathy (CBM) is a rare congenital myopathy characterized by the presence of numerous cytoplasmic bodies in the skeletal muscle fibers.Following the first report of CBM by Nakashima, et al. in 1970 [1], the literature now contains more than 30 cases.Clinical features vary from severe congenital type to mildly progressive adult-onset type.We experienced a case of very severe congenital type CBM, which manifested as generalized hydrops fetalis at 33 weeks of gestation.

Case Report
A 27-year-old, gravida 3, para 1 Japanese woman was transferred to our hospital because of fetal pleural effusion and polyhydroamnios at 33 weeks of gestation.She had a family history of amyotrophic lateral sclerosis in her maternal uncle.Her first child, a 3-yearold boy, was healthy.The pregnancy had been uneventful until 33 weeks, when the patient noticed the fetus was less active than before.On admission, the fetus had bilateral pleural effusion, ascites, and subcutaneous edema.The amniotic fluid index was more than 30 cm.Fetal ejection fraction of the left ventricle was 60 to 80%, and the heart rate was 140-150 beat per minute without arrhythmia.There were no signs of anomaly.Screening tests results were blood type A, Rh positive, indirect Coombs test negative, 75 g OGTT normal, TORCH screening negative, and Kleihauer-Betke staining negative.At 36 weeks and 0/7, the biophysical profile score was 2 of 10.A nonreactive result and prolonged deceleration was seen on fetal heart rate monitoring and the baby was delivered by cesarean section.

Comments
A review of the English literature searched by the keywords of "cytoplasmic body myopathy" and "infant" reveals that this is the first report of congenital severe CBM associated with hydrops fetalis.Nonimmune fetal hydrops is the end feature of a variety of pathophysiologic mechanisms.It is sometimes accompanied by congenital myopathy such as congenital myotonic dystrophy or nemaline myopathy.The etiologic relationship between congenital myopathy and fetal hydrops has not been clearly established.
There are several pathophysiological processes proposed to account for the pathway of fetal hydrops.The pathogenesis leading to hydrops is unclear in this case.It was not caused by cardiac failure because the cardiac function was normal.Hypoplasia of the thorax may be the contributing factor because of interference with amniotic fluid transfer through the lung.The lymphatic abnormality might have resulted in increased interstitial fluid and caused fetal hydrops with chylothorax.
Cytoplasmic bodies were initially reported by Engel in 1962 in patients with advanced denervation and myotonic dystrophy [2].Since then, cytoplasmic bodies have been identified in a variety of neuromuscular diseases including metabolic disorders, muscular dystrophies, and neurogenic atrophies.Cytoplasmic bodies are the morphologic hallmark of sporadic as well as familial congenital a b

Figure 1 :
Figure 1: Biopsy from left quadriceps femoris muscle.a) Optical microscopic observations modified Gomori trichrome stain.Cytoplasmic bodies are apparent in a variety of muscle fibers.X 260; b) Electron micrograph shows a cytoplasmic body with a dense central core and radiating peripheral filaments.X 10,000.

Table 1 :
Clinical and laboratory data in reported cases of congenital cytoplasmic body myopathy.