Paediatric rhabdomyosarcoma: MyoD1 demonstration in routinely processed tissue sections using wet heat pretreatment (pressure cooking) for antigen retrieval.

AIMS: To investigate wet heat pretreatment (pressure cooking) as a means of antigen retrieval for demonstration of MyoD1 in paraffin wax embedded tissue. METHODS: Routinely processed tissue sections of transmission electron microscope confirmed cases of rhabdomyosarcoma were stained immunohistochemically with the MyoD1 antibody. Antigen retrieval was achieved by wet heat pretreatment of the tissue sections. RESULTS: MyoD1 was stained successfully in all seven cases. The protein was localised to nuclei and cytoplasm depending on the type of tumour cell. CONCLUSIONS: Wet heat pretreatment for antigen retrieval from routinely processed tissue sections permits excellent subsequent immunostaining for MyoD1 in rhabdomyoblasts.

Malignant ectomesenchymoma in childhood.

Five childhood malignant ectomesenchymomas are reported from three centers in three countries. The children were all younger than 3 years (four less than 12 months), four were boys, and four tumors were sited in the pelvis or external genitalia. All tumors had distinctive light microscopic features of rhabdomyosarcoma and three also demonstrated small numbers of included neuronal cells. Immunohistochemical studies and transmission electron microscopy revealed the additional presence of neurogenic components in the remaining two patients. An additional epithelial component was found by immunohistochemistry in one tumor, which suggests a pluripotential origin that still requires karyotypic investigation. Aggressive chemotherapy and adequate surgical excision have thus far been effective in providing disease-free follow-up for periods of 7 to 50 months. It is implied that because the biological behavior and morphology closely resemble those of rhabdomyosarcoma and because the neurogenic component is often inconspicuous, many malignant ectomesenchymomas may be misdiagnosed as rhabdomyosarcomas.

Syphilitic placentitis: an immunopathy.

The placentas of eight infants with congenital syphilis were examined by both immunohistochemical and immunofluorescent techniques. Significant IgM, C3 and rheumatoid factor reactivity were observed in all the syphilitic placentas. We postulate that their presence plays an important role in the evolution of the pathological changes.

A case of the Neu-Laxova syndrome: prenatal ultrasonographic monitoring in the third trimester and the histopathological findings.

A diagnosis of the Neu-Laxova syndrome was made by ultrasonography in the third trimester of pregnancy. Initial ultrasonographic examination, at approximately 28 wk gestation, showed intrauterine growth retardation (IUGR), hypoechoic skeletal structures, kyphosis, feeble fetal activity, and restricted limb movement. Subsequent sonograms showed microcephaly with a receding forehead and prominent eyes, generalised edema and flexion deformities of limbs. Late third trimester findings included polyhydramnios, swelling and webbing of the knee and elbow joints, and severe edema of the hands and feet, giving the impression of absent digits. The clinical features of this case are consistent with group II of Curry's classification of the Neu-Laxova syndrome [Curry, 1982]. The histopathological findings, a triad of dermatological features, poor cortex formation of the long bones, and central nervous system (CNS) dysgenesis, are discussed. In view of the 25% recurrence rate, at risk pregnancies should be carefully monitored by ultrasonography: at 6-8 wk for accurate dating, at 12-16 weeks for active fetal limb movement, and at 16-24 wk for facial and skeletal anomalies, the detection of IUGR, and polyhydramnios.

Mucocutaneous lymph node syndrome (Kawasaki disease). A report of 2 cases.

Two cases of Kawasaki disease, both with cardiac involvement, are reported in South African children and the diagnostic problems are discussed. In patient 1 an ECG showed the development of an inferior myocardial infarction, and in patient 2 on aneurysm of the left coronary artery was found at postmortem examination.

Neonatal mortality in a Black urban community.

An autopsy study carried out on 103 neonates showed a high incidence of twins, mainly second twins. The commonest cause of death was asphyxia, predominantly among the small-for-gestational-age (SGA) babies, and this was possibly associated with placental insufficiency. Hyaline membrane disease (HMD) was the next most common cause and occurred in the majority in the first 24 hours. Pulmonary haemorrhage, which used to be common in this population, was very rare. More than 50% of the deaths occurred on the first day of life.