Genetic and morphological findings in progressive familial intrahepatic cholestasis (Byler disease [PFIC-1] and Byler syndrome): evidence for heterogeneity.

Byler disease (ByD) is an autosomal recessive disorder in which cholestasis of onset in infancy leads to hepatic fibrosis and death. Children who have a clinically similar disorder, but are not members of the Amish kindred in which ByD was described, are said to have Byler syndrome (ByS). Controversy exists as to whether ByD and ByS (subtypes of progressive familial intrahepatic cholestasis [PFIC]) represent one clinicopathological entity. The gene for ByD has been mapped to a 19-cM region of 18q21-q22. PFIC caused by a lesion in this region, including ByD, can be designated PFIC-1. Examination of haplotypes in siblings with ByS in two unrelated non-Amish families showed that the gene(s) responsible for their disorder(s) did not lie in the PFIC-1 candidate region. On light microscopy and transmission electron microscopy (TEM), liver tissue differed between Amish children with PFIC-1, who had coarsely granular bile and at presentation had bland intracanalicular cholestasis, and the children with ByS in the two non-Amish families, who had amorphous or finely filamentous bile and at presentation had neonatal hepatitis. Bile acid composition of bile also differed: In the Amish children with PFIC-1 and in one ByS family, the proportional concentration of chenodeoxycholic acid (CDCA) in bile was low compared with normal bile; in the other ByS family, it was only slightly reduced. Genetic analysis and light microscopy and TEM of liver may help distinguish PFIC-1 from other forms of ByS.

IgA nephritis in a patient with Alagille syndrome and a transplanted liver.

Alagille syndrome (arteriohepatic dysplasia) is a major cause of intrahepatic cholestasis in infancy. The present report describes a patient with Alagille syndrome who presented with hematuria and IgA nephritis 7 years after an orthotopic liver transplantation and immunosuppression. This patient suggests that glomerular lipidosis is not an inherent feature of the Alagille syndrome, and that IgA nephritis may develop in spite of ongoing immunosuppressive treatment.

Gastrointestinal microvillus inclusion disease.

A 3-year-old girl of Navajo heritage had intractable diarrhea beginning at 4 days of age and resulting in long-term hyperalimentation. Investigation before multivisceral transplantation included biopsies of the rectum, stomach, duodenum, and liver. The diagnosis of microvillus inclusion disease was established by documentation of microvillus inclusions in duodenal epithelial cells. A trial of somatostatin therapy was ineffective in controlling the diarrhea. Subsequently, a multivisceral organ transplant provided a unique opportunity to establish the gastrointestinal extent of involvement of this disease. Ultrastructural microvillus inclusions were identified in the duodenum, jejunum, ileum, and colon, but not in the gallbladder. A few inclusions also were documented in gastric antral epithelial cells. Alkaline phosphatase stains performed on paraffin-embedded material showed a few inclusions in the antrum of the stomach and many inclusions throughout the small intestine, primarily in surface epithelial cells but also in upper crypt cells.

A new variant of type IV glycogenosis: deficiency of branching enzyme activity without apparent progressive liver disease.

Type IV glycogenosis is due to branching enzyme deficiency and is usually manifested clinically by progressive liver disease with cirrhosis and hepatic failure between the second and fourth years of life. We describe a 5-year-old boy who, following an acute febrile illness at 2 years of age, was first noted to have hepatomegaly with mildly elevated serum transaminase levels. Liver biopsy revealed hepatic fibrosis with periodic-acid Schiff-positive, diastase-resistant inclusions in hepatocytes and fibrillar inclusions characteristic of amylopectin by electron microscopy. Enzymatic assay revealed deficient hepatic branching enzyme activity with normal activity of glucose-6-phosphatase, debranching enzyme and phosphorylase activities. During the succeeding 3 years, he grew and developed normally with apparent resolution of any clinical evidence of liver disease and only intermittent elevation in serum transaminase levels associated with fever and prolonged fasting. Repeat liver biopsy at 4 years of age showed persistence of scattered hepatocellular periodic-acid Schiff-positive, diastase-resistant inclusions, but no progression of hepatic fibrosis in spite of persistent deficiency of hepatic branching enzyme activity. Skeletal muscle and skin fibroblasts from the patient also showed deficient enzyme activity. Skin fibroblasts from both parents exhibited half the normal control activity, suggesting a heterozygote state. This is the first documented patient with deficiency of branching enzyme but without evidence of progressive hepatic disease. This patient, coupled with reports of other patients with late onset hepatic or muscle disease with branching enzyme deficiency, suggests that the defect resulting in Type IV glycogen storage disease is more heterogenous and possibly more common than previously suspected.

Malignant ectomesenchymoma of soft tissue. Report of two cases and review of the literature.

The clinical and pathologic findings of two patients with malignant ectomesenchymomas of soft tissue are reported. Malignant ectomesenchymomas are a composite of ganglion cells or neuroblasts and one or more malignant mesenchymal elements, usually rhabdomyosarcoma. Our first case was composed of ganglioneurosarcoma plus rhabdomyosarcoma, the second composed of neuroblastoma plus rhabdomyosarcoma. The name is derived from the suggestion that they arise from pluripotential ectomesenchyme. An English language literature search revealed 11 other cases that arose in soft tissue and had adequate clinicopathologic data. Of the 13 cases, 10 occurred in infants, three occurred in adults, and nine were males. Six patients were alive and free of disease at last follow-up (range, 0.6-12 years; mean, 3.4 years), four patients had died of tumor (within 0.5-3.3 years; mean, 1.3 years), one case had died of Adriamycin (doxorubicin) toxicity, and two cases had been lost to follow-up. Complete surgical resection is the mainstay of treatment and chemotherapy appears to be important.

The neuroectodermal tumor of bone.

Four small round cell malignant tumors of bone occurring in children are described. There was no catecholamine secretion and the clinical, radiologic, and biopsy diagnosis in each was Ewing's sarcoma. Glycogen was sparse both on imprints and in tissue sections. The tumors, when extensively sampled, had areas of a lobular growth pattern and Homer Wright rosettes. The rosettes were always focal and varied in complexity from case to case; they were rudimentary in one instance and markedly fibrillar in the most obvious instance. Neuron-specific enolase was demonstrated in tissue sections and in longterm cell cultures from three of the tumors. The cultured cells put out moderately long beaded processes in serum-free medium but had no catecholamine fluorescence. Electron microscopy of the tumor rosettes and the cultured cells showed processes containing aggregates of microtubules and only one case had rare neurosecretory granules. This study suggests that some small round cell tumors of bone and soft tissue in children, which present as Ewing's sarcoma, are neuroectodermal in nature.

Studies on the nature of fibrillar nuclei. Distinction from viral nucleocapsid.

Despite sufficient evidence to the contrary, fibrillar nuclei continue to be claimed by some to represent paramyxovirus. In a review of the electron-microscopic material, fibrillar nuclei were found in a variety of tissues and situations where a viral etiology is unlikely. Fibrillar nuclei were most often found in postmortem and formalin-fixed material. These nuclei were also experimentally produced in postmortem human lung with formalin fixation followed by a deionized water rinse. It is concluded that fibrillar nuclei do not represent virus, but chromatin, and it is believed that this chromatin appearance is related to cell injury and to tissue processing. It is also believed that fibrillar nuclei occur with much greater frequency than realized. These nuclei are usually ignored during examination of specimens by light and electron microscopy because these specimens are usually being selectively screened for other changes and perhaps because a clear understanding of their significance is still lacking.

Morphology of human T lymphocyte clones.

Six human T lymphocyte clones, characterized as to cytolytic activities and several surface markers, were investigated for possible morphologic correlates of function. Cytotoxic T lymphocyte clones and natural killer-like clones had basically similar morphology, but cytotoxic T lymphocytes tended to cluster in groups and had many more lipid bodies, whereas natural killer-like cells had fewer intercellular contacts and had more and larger electron-dense bodies. Dense bodies were also quite prominent in noncytotoxic clones. The latter were distinctive in having a minority of very large cells (10 to 16 microns) with many microvilli, scattered among the majority of 5- to 8-microns diameter cells.

Glycogen in neuroblastomas. A light- and electron-microscopic study of 40 cases.

A light- and electron-microscopic review of 40 cases diagnosed at Children's Hospital of Pittsburgh as ganglioneuroblastoma, neuroblastoma, or small round cell tumor-probably neuroblastoma disclosed four cases that contained abundant glycogen. Two were unquestionable neuroblastomas by electron microscopy; one was primary in the adrenal gland, the other in the mediastinum. In the third case, a paraspinal tumor, the light-microscopic appearance was suggestive or neuroblastoma, but no catecholamine granules or neural processes were demonstrated in the material available for electron microscopy. The fourth case was an undifferentiated malignant tumor in the pectoralis muscle of a 12-year-old girl. By electron microscopy, neural processes were demonstrated and the tumor was classified as peripheral neuroblastoma. Of the remaining 36 cases, electron microscopy readily indicated a diagnosis of neuroblastoma or glangioneuroblastoma in 35 of them. In the other case, the tissue had been fixed in formalin and only a few catecholamine granules were found after an extensive search.

Fine structural observations of the liver in alpha-1-antitrypsin deficiency.

Morphologic studies of liver tissue in individuals deficient in alpha-1-antitrypsin (alpha-1-AT) have established the presence of membrane-delimited deposits which are diastase resistant, perodic acid-Schiff positive, sialic acid deficient, and immunologically related to serum alpha-1-AT. The molecular basis for the accumulation alpha-1-AT-like substance in hepatocytes and the serum deficiency in alpha-1-AT patients is unknown. In an effort to gain insight into the membrane sites involved in the storage of the alpha-1-AT-like material, we examined liver biopsies by light and electron microscopy from 3 children with homozygous PiZZ deficiency and varying degrees of liver pathology. Contrary to the more widely held belief that accumulation occurs primarily in the rough endoplasmic reticulum, we find the earliest and greatest accumulation of alpha-1-AT-like material in smooth endoplasmic reticulum of hepatocytes. We have combined our ultrastructural observations with the current knowledge which is available concerning the structural properties of M-type and Z-type alpha-1-AT and have proposed a model which may explain the basis for the hepatic accumulation of alpha-1-AT-like material and the serum deficiency state in the PiZZ genotypes.