Monoclonal antibody NB84 in the differential diagnosis of neuroblastoma and other small round cell tumors.

Two hundred fifty-five well-characterized formaldehyde-fixed and paraffin-embedded small round cell tumors mainly from children and young adults including 105 neuroblastomas were immunohistochemically analyzed with the NB84 monoclonal antibody raised to neuroblastoma cells. Most of the undifferentiated neuroblastomas (21 of 22) and all 83 differentiated neuroblastomas reacted with NB84, but none of these tumors were CD99 positive. Compared with synaptophysin, NB84 was more sensitive, although less specific, in the identification of neuroblastoma in formaldehyde-fixed tissue. In addition to neuroblastoma, skeletal and extraskeletal Ewing's sarcoma and medulloblastoma showed NB84 reactivity in approximately 20% of cases, and 50% of desmoplastic small round cell tumors showed positive cells, usually in smaller numbers than the neuroblastomas. The NB84 reactivity was seen slightly more commonly in morphologically defined (rosette-positive) cases of peripheral primitive neuroectodermal tumors than in Ewing's sarcoma. However, the NB84 positivity did not correlate with the expression of other neural markers (neurofilament proteins, CD57, and synaptophysin) in these tumors. All other small round cell tumors including rhabdomyosarcomas, Wilms' tumors, and lymphomas were NB84 negative. In the case of NB84-positive tumors other than neuroblastoma, their specific reactivity for other markers was useful (Ewing's sarcoma CD99 positive, desmoplastic small round cell tumor desmin and keratin positive). The NB84 monoclonal antibody is a useful reagent to separate neuroblastoma from other small round cell tumors. In problem cases it is best used in a panel together with other markers that address the significant differential diagnostic alternatives.

Prognostic signs in the surgical management of plexiform neurofibroma: the Children's Hospital of Philadelphia experience, 1974-1994.

OBJECTIVES: To estimate the rate of progression of plexiform neurofibroma after surgery and to identify prognostic factors that predict progression. STUDY DESIGN: A retrospective review of the inpatient and outpatient records of 121 patients, who had 302 procedures on 168 tumors over a 20-year period at a single large pediatric referral center. Data on age, location, indication for surgery, and extent of resection was analyzed for prognostic significance. RESULTS: The overall freedom from progression was 54%. Children < 10 years old had a shorter interval of tumor control than older children (p = 0.0004). Tumors of the head/neck/face fared worse than tumors of the extremities (p = 0.0003). Less extensive resection predicted shorter interval to progression (p < 0.0001). Indication for surgery was not of prognostic importance. In multivariable analysis older age and location in the extremities were predictors of a better outcome. CONCLUSIONS: Tumor progression is a serious problem for children with plexiform neurofibroma. Younger children, children with tumors of the head/neck/face, and tumors that cannot be nearly completely removed are at particular risk. These data may be useful in helping clinicians decide which patients and which tumors are most likely to benefit from surgical intervention.

Lipoblastoma/lipoblastomatosis: a clinicopathologic study of 25 tumors.

Lipoblastoma/lipoblastomatosis is an uncommon benign adipose tissue tumor of children. Since 1958, 25 of these tumors from 24 patients have been reviewed in the Department of Pathology at The Children's Hospital of Philadelphia. Tumors were resected from 19 boys (79%) and five girls, and 20 patients (84%) were < or =5 years of age at diagnosis. Twenty-three tumors presented as painless superficial soft-tissue masses; one tumor was retroperitoneal and was discovered because of vomiting; one hand tumor was present at birth. Tumors occurred in an extremity (n = 11 patients), the head and neck (n = 5), groin (n = 2), axilla (n = 2), back (n = 1), chest (n = 1), flank (n = 1), labia (n = 1), and retroperitoneum (n = 1). Thirteen tumors occurred on the left side, and five occurred on the right. Lesions measured 1.0-21.0 cm in greatest dimension; 15 of 25 (60%) measured < or =5.0 cm. The largest (retroperitoneal) tumor weighed 450 g. Eleven tumors were discrete lipoblastoma, and 14 had irregular margins (lipoblastomatosis). Microscopically, the tumors displayed adipocytes in different stages of maturation; lobules bordered by septae that were cellular in 11 cases; prominent blood vessels in 19 cases; and myxoid foci in 13 cases. Chart review of 22 patients showed that one tumor recurred 4 years after resection; one tumor recurred after 7 years as fibrolipoma; and one incompletely resected tumor enlarged and at second resection was lipoma. There were no metastases. Three patients also had hemangioma. Juvenile aponeurotic fibroma occurred in one patient near the site of resection of a lipoblastoma 4 years earlier. We conclude that lipoblastoma/lipoblastomatosis behaves benignly, occurs in both superficial and deep sites, occasionally attains large size, may mature, can recur, and may be associated with other benign soft-tissue lesions. Complete surgical excision is the treatment of choice.

Detection of gene fusions in rhabdomyosarcoma by reverse transcriptase-polymerase chain reaction assay of archival samples.

Alveolar rhabdomyosarcoma is a pediatric soft-tissue tumor that is often difficult to distinguish from other small round-cell tumors. The PAX3-FKHR and PAX7-FKHR gene fusions that result from chromosomal translocations in this tumor provide potential molecular diagnostic markers. To apply these molecular markers to commonly available archival material, we used reverse transcriptase-polymerase chain reaction and oligonucleotide hybridization methodology to develop an assay capable of identifying PAX3-FKHR and PAX7-FKHR fusion transcripts in formalin-fixed, paraffin-embedded tissue. Use of a control assay for wild-type FKHR mRNA indicated that RNA was successfully isolated, reverse-transcribed, and amplified in 15 of 16 archival cases. Comparison of assay results for the PAX3-FKHR and PAX7-FKHR fusions with standard molecular assays of paired frozen material revealed that all eight cases of known fusion-positive rhabdomyosarcoma were correctly identified and distinguished as PAX3-FKHR or PAX7-FKHR. The seven cases of known fusion-negative rhabdomyosarcoma showed no evidence of either product. These results indicate that we have developed a molecular assay that accurately identifies the fusion transcripts characteristic of alveolar rhabdomyosarcoma in archival samples. This assay will be useful for diagnosis and for retrospective clinicopathologic correlative studies.

Immunohistochemical analysis of Bcl-2, Bcl-X, Mcl-1, and Bax in tumors of central and peripheral nervous system origin.

The expression of Bcl-2, Bcl-X, Mcl-1, and Bax was examined by immunohistochemical methods in 93 tumors of nervous system origin, including 49 gliomas (30 astrocytomas and 19 glioblastoma multiforme (GMs)), 16 medulloblastomas (MBs), 19 neuroblastomas (NBs; 9 undifferentiated and 10 differentiated), and 9 miscellaneous neuroectodermal neoplasms. Among the 49 gliomas, immunopositivity (defined as > or = 10%) was observed for Bcl-2 in 45 (92%), Bcl-X in 48 (98%), Mcl-1 in 49 (100%), and Bax in 48 (98%) of 49 specimens. In 11 (37%) of 30 astrocytomas (WHO grades I to III), the tumor specimens were composed predominantly of malignant cells with strong-intensity Bcl-2 immunostaining, whereas none of the 19 GMs (WHO grade IV) exhibited strong-intensity Bcl-2 immunoreactivity (P = 0.001). Similarly, Mcl-1 immunointensity was strong in 15 (50%) of 30 astrocytomas, compared with only 2 (11%) of 19 GMs (P = 0.005). The percentage of Mcl-1-immunopositive tumor cells was also higher in astrocytomas than GMs (P < 0.002). Thus, contrary to a priori expectations, the expression of the anti-apoptotic proteins Bcl-2 and Mcl-1 was significantly higher in astrocytomas than in GMs. Of the 16 MBs, immunopositivity was found for Bcl-2 in 4 (25%), Bcl-X in 9 (56%), Mcl-1 in 8 (50%), and Bax in 16 (100%) of the cases. The intensity of immunostaining was strong for Bcl-2 in only 1 (6%) specimen, for Bcl-X in 3 (19%), and for Mcl-1 in 2 (12.5%), in contrast to Bax immunostaining, which was strong in 12 (75%) tumors. Significantly higher percentages of Bax-immunopositive tumor cells were also found in MBs, compared with Bcl-2, Bcl-X, and Mcl-1 (P < 0.0001). All 19 NBs were immunopositive for Bcl-2, Bcl-X, Mcl-1, and Bax. Higher percentages of Bcl-X- and Mcl-1-immunopositive tumor cells were observed in well differentiated tumors (P = 0.04 and 0.004, respectively). The intensity of Mcl-1 immunostaining was also generally higher in differentiated than undifferentiated NBs (strong immunointensity in 7 of 10 versus 0 of 9; P = 0.002). Conversely, strong-intensity Bax immunostaining was associated with undifferentiated histology (5 of 9 (56%) versus 1 of 10 (10%); P = 0.03). Taken together, these findings begin to delineate trends in the regulation of the relative levels of the Bcl-2 family proteins, Bcl-2, Bcl-X, Mcl-1, and Bax in gliomas, MBs, NBs, and some of their histological subtypes. The suggestion that expression of some of these Bcl-2 family genes may be differentially regulated in association with tumor progression and differentiation provides insights into the diverse biology and clinical behavior of these tumors of nervous system origin.

Familial neuroblastoma: a three-generation pedigree and a further association with Hirschsprung disease.

Like the other embryonal cancers of childhood, neuroblastoma occasionally occurs within families. We now provide an update on a nuclear family in which seven individuals are affected with neuroblastoma, inherited in an autosomal dominant fashion over three generations. In addition, two of these individuals are also affected with Hirschsprung disease. This family may lend insight into the molecular pathogenesis of familial neuroblastoma.

Identification of subsets of neuroblastomas by combined histopathologic and N-myc analysis.

BACKGROUND: Neuroblastomas show different histopathologic phenotypes, and the tumor cells can carry normal or multiple copies of the N-myc proto-oncogene (MYCN). Studies of the N-myc gene and histopathology of untreated primary neuroblastomas have demonstrated that both these factors are important in risk assessment. PURPOSE: Our purpose was to determine if there are any associations between N-myc gene copy number, histopathologic features, clinical stage, and progression-free survival (PFS) and if joint analyses of histopathology and N-myc gene copy number improve risk assessment. METHODS: The histopathologic phenotype and N-myc gene copy number were determined for 232 biopsy/surgery specimens obtained from untreated primary neuroblastoma patients. Tumors were classified as having favorable or unfavorable histology on the basis of Schwannian stroma (rich versus poor), neuroblastic differentiation (differentiating versus undifferentiated), and mitosis-karyorrhexis (fragmenting nucleus) index (MKI; high, intermediate, or low) in the context of age at diagnosis (Shimada classification). N-myc gene amplification was considered significant when the gene copy number was at least 10-fold higher than normal as determined by Southern blot analysis. Otherwise, tumors were classified as nonamplified for N-myc. RESULTS: Among 19 stroma-rich tumors, 11 had grossly visible neuroblastic nodules, and two of these had N-myc amplification. Of 213 stroma-poor tumors, 51 had N-myc amplification, all of which were undifferentiated, and 45 (88% of 51) had high MKI. This histologic phenotype was present in less than 10% of tumors with nonamplified N-myc. Of 162 stroma-poor tumors that showed nonamplified N-myc, 45 (28%) were differentiating and 121 (75%) had low MKI. Neuroblastomas of clinical stages I, II, and IV-S nearly always had favorable histology and no amplification of N-myc. Stage III (regional) and particularly stage IV (metastatic) tumors, however, frequently had unfavorable histologic features with or without N-myc amplification. The estimated PFS at the end of 4 years after diagnosis was 83% for patients whose tumors had favorable histology and no N-myc amplification. The estimated PFS for the patients whose neuroblastomas had unfavorable histology, however, was 29% without and 13% with N-myc amplification, respectively. Subsets of patients with stage II, III, or IV disease were identified by both histologic evaluation and N-myc analysis. Multivariate Cox regression analysis indicated that both the histologic and N-myc-based stratifications provided prognostic information that was independent of staging. CONCLUSIONS: Neuroblastomas with N-myc amplification have a characteristic histopathologic phenotype and an aggressive clinical course. In contrast, neuroblastomas without N-myc amplification exhibit a wide range of histologic features that can define prognostic subsets.

Molecular assays for chromosomal translocations in the diagnosis of pediatric soft tissue sarcomas.

OBJECTIVE: To compare molecular assays for characteristic chromosomal translocations with standard histopathologic and cytogenetic analysis in the differential diagnosis of pediatric soft tissue sarcomas. DESIGN: Blinded comparison with histopathologic diagnosis. SETTING: Tertiary care children's hospital. PATIENTS: A total of 79 soft tissue sarcoma patients with frozen tumor tissue and histopathologic slides available for review. METHODS: The RNA from the tumors was assayed by the reverse transcriptase-polymerase chain reaction. These assays detect PAX3-FKHR and PAX7-FKHR chimeric transcripts in alveolar rhabdomyosarcoma, EWS-FLI1 and EWS-ERG chimeric transcripts in Ewing's sarcoma, and EWS-WT1 chimeric transcripts in desmoplastic small round cell tumor. MAIN OUTCOME MEASURES: The polymerase chain reaction findings were compared with cytogenetic and histopathologic results. RESULTS: These assays detected chimeric transcripts in all cases in which translocations were found by standard cytogenetics as well as additional cases without cytogenetically detectable translocations. PAX3-FKHR or PAX7-FKHR fusions were present in 18 of 21 alveolar rhabdomyosarcomas, two of 30 embryonal rhabdomyosarcomas, and one of seven undifferentiated sarcomas. EWS-FLI1 or EWS-ERG fusions were detected in six of eight Ewing's sarcomas and one of seven undifferentiated sarcomas. The EWS-WT1 fusion was found in three of three desmoplastic small round cell tumors. CONCLUSIONS: Molecular assays for specific gene fusions provide a genetic approach to the differential diagnosis of soft tissue sarcomas. The genetic categories correspond closely to the standard histopathologic categories. The polymerase chain reaction assays for chimeric transcripts are useful tools for the rapid and objective assessment of pediatric soft tissue sarcomas.

Immunohistochemical analysis of the Bcl-2 oncoprotein in human neuroblastomas. Comparisons with tumor cell differentiation and N-Myc protein.

BACKGROUND: The bcl-2 gene encodes a 26-kilodalton integral membrane oncoprotein that is noteworthy for its function as a blocker of programmed cell death, and ability to render cells resistant to killing by chemotherapeutic drugs and x-irradiation. EXPERIMENTAL DESIGN: To determine the in vivo patterns of bcl-2 expression in neuroblastomas (NBs), tumor specimens derived from 17 children with NB or ganglioneuromas were immunohistochemically evaluated using formalin-fixed, paraffin-embedded material and antibodies specific for the Bcl-2 and N-Myc proteins, or various markers typically used to assess the differentiation status of these tumors, including neuron-specific enolase, S-100 protein, beta 2-microglobulin (beta 2M) and the intermediate filament proteins, vimentin, and neurofilament light- and medium-chains. RESULTS: Using two-color immunohistochemical methods, Bcl-2 protein was found exclusively in tumor cells that did not contain N-Myc, an oncoprotein previously associated with poor prognosis in NB. Levels of Bcl-2 immunostaining were heterogeneous in the undifferentiated small, round cells typically seen in tumors with aggressive histology, and ranged from essentially undetectable, to strong in intensity. Somewhat higher levels of Bcl-2 immunostaining were found in the slightly larger, more differentiated neuroblastic cells that had more generous cytoplasm in these neoplasms. In contrast to the heterogeneous levels of Bcl-2 seen in undifferentiated NBs, Bcl-2 immunoreactivity was uniformly present at high levels in tumor cells that were more differentiated and judged to be similar to immature ganglion cells at an intermediate stage of neuronal differentiation, based on morphologic characteristics and immunophenotyping with antibodies specific for various differentiation markers. The still more differentiated ganglionic cells seen in ganglioneuroblastomas and ganglioneuromas exhibited much less intense immunoreactivity with anti-Bcl-2 antibodies, suggesting down-regulation of bcl-2 during final terminal differentiation. In contrast to cells with neuronal features, the stromal Schwann cells were uniformly negative for Bcl-2 protein in all histologic grades of tumors. Thus, bcl-2 expression in NBs was limited to cells of the neuronal lineage and tended to be highest in tumor cells with the characteristics of ganglionic cell precursors. The expression of bcl-2 in the normal fetal and postnatal adrenal medulla and sympathetic ganglia paralleled that seen in NBs, consistent with previous suggestions that NB reflects a block in the normal differentiation process. CONCLUSIONS: Taken together, these findings indicate that the levels of the Bcl-2 protein are developmentally regulated in normal and neoplastic cells of the sympathetic branch of the autonomic nervous system, and suggest that this oncoprotein may be useful as a differentiation marker for subclassification of NBs for prognostic purposes and for investigations of normal neuronal maturation. Furthermore, strong Bcl-2 immunoreactivity was detected in islets of residual tumor cells in 6 of 7 specimens obtained from 5 patients after therapy, suggesting that this oncoprotein may be cytoprotective for NB cells in vivo.

Immunohistochemical evaluation of myeloid leukemia infiltrates (granulocytic sarcomas) in formaldehyde-fixed, paraffin-embedded tissue.

Paraffin sections of granulocytic sarcomas (GS) (n = 30) were immunohistochemically evaluated for CD3, CD15 (LeuM1), CD20 (L26), CD31, CD34, CD43, CD45, CD68 (KP1), lysozyme, myeloperoxidase (BM1), CD45RO (UCHL1), and LN5 with an avidin-biotin amplification system and a peroxidase-based color development system with DAB as a chromogen. CD45 positivity was present in all lymphomas and 24 of 25 granulocytic sarcomas. Lysozyme and CD43 labeled 26 of 29 granulocytic sarcomas, showing intense cytoplasmic staining. LN5 (membrane-staining) and CD68 (subtle cytoplasmic caplike staining) were found in 20 of 30 cases, often only focally. BM1 and CD15 mainly labeled maturing granulocytes and mostly were negative in primitive myeloid cells. Myeloid progenitor cell antigens CD31 and CD34 were seen in 7 and 12 of 30 cases, respectively. They seemed to recognize different subsets of myeloid leukemia infiltrates (16 cases positive for at least one); the use of CD31 and CD34 for defining these subsets should be evaluated further. Features suggesting a dual phenotype--T-cell and myeloid (positive for CD3, CD68, and lysozyme)--were documented in two cases. In contrast, lymphoblastic lymphomas (n = 4) were positive for CD3 and CD43 but negative for CD68, lysozyme, CD31, CD34, LN5, and myeloperoxidase. Lymphocytic lymphomas (n = 10) were positive for CD20 and CD43 but negative for all other markers. Small, round-cell tumors (n = 15) were negative for all markers. If T-cell and B-cell differentiation can be excluded with other markers, CD43+ is a sensitive marker for myeloid differentiation. Our results show that several markers are useful in the identification of myeloid leukemia infiltrates and in distinguishing them from lymphoblastic and lymphocytic lymphomas and small round-cell tumors in formaldehyde-fixed, paraffin-embedded tissue.

Plasticity of neuroblastoma tumor cells to differentiate along a fetal adrenal ganglionic lineage predicts for improved patient survival.

We have recently presented a model of human adrenal medullary histogenesis that incorporates all neural crest-derived lineages (chromaffin, sustentacular, and ganglionic) known to compose this tissue. To determine if neuroblastomas correspond to the arrested maturation of embryonal adrenal medullary cells, we evaluated the expression of adrenal medullary developmental markers in 81 neuroblastoma tumors. We found that patterns of chromaffin-related gene expression in these tumors correlated exactly with the patterns observed during maturation of adrenal medullary cells (P2 < 10(-5). In a multivariate Cox proportional hazards analysis of developmental marker expression and other well-recognized prognostic variables, evidence of maturation along a fetal ganglionic lineage, as monitored by HNK-1 immunoreactivity (relative risk of 6.42, P2 = 0.0001), and age at diagnosis (relative risk of 5.05, P2 = 0.0042) were independent and significant prognostic indicators of patient survival. These studies demonstrate that neuroblastomas correspond to embryonal adrenal medullary cells arrested at recognizable stages during development, and that evidence of maturation along a fetal ganglionic lineage appears to have major importance in predicting patient survival.

True hermaphroditism: sonographic demonstration of ovotestes.

A 15-year-old boy with normal external genitalia presented with severe bilateral gynecomastia, intermittent painful scrotal swelling, and a recent history of scrotal trauma. Ultrasound (US) revealed testicles of normal size with diffusely heterogeneous echotexture due to scattered cysts. Ovotestes were found at surgery and pathologic examination. Bilateral partial gonadectomies were performed. Four months later he had testicular pain and swelling. US revealed bilateral multiseptate cystic masses. After repeat surgery, he is now free of symptoms. The diagnosis of true hermaphroditism and ovotestis should be considered in a phenotypic male adolescent with gynecomastia when testicular parenchyma is heterogeneous at US because of multiple scattered cysts.

Evaluation of the Shimada classification in advanced neuroblastoma with a special reference to the mitosis-karyorrhexis index: a report from the Childrens Cancer Study Group.

Histopathology of 46 cases of Stage III and Stage IV neuroblastoma collected at the Childrens Cancer Study Group Pathology Center was reviewed independently by two pathologists to formulate essential steps in the determination of the mitosis-karyorrhexis index (MKI), to assess interobserver concordance, and to evaluate prognostic significance of the Shimada classification system. "Absolute" agreement (obtained after the review by both pathologists) or "consensus" agreement (obtained after the second review of cases with initial discrepancy) was achieved with respect to category of MKI in 93% of 40 stroma-poor neuroblastomas and prognostic subgrouping in 98% of the total cases. This classification system distinguished favorable from unfavorable prognostic subgroups significantly (P = 0.0002), and the prognostic effects were largely unaltered when adjusted for age and stage of the patients (P = 0.0005) in this series.

Insulin-like growth factor II-mediated proliferation of human neuroblastoma.

Neuroblastoma is an embryonal tumor that typically arises in cells of the developing adrenal medulla. IGF-II mRNA is expressed at high levels in the adrenal cortex before birth but it is not detectable until after birth in the adrenal medulla. Neuroblastoma cell lines corresponding to early adrenal medullary precursors did not express IGF-II, although all three cell lines we tested were growth stimulated by IGF-II. Cell lines corresponding to more mature adrenal medullary cells expressed IGF-II, and one, SK-N-AS, grows by an IGF-II autocrine mechanism (J. Clin. Invest. 84:829-839) El-Badry, Romanus, Helman, Cooper, Rechler, and Israel. 1989. An examination of human neuroblastoma tumor tissues for IGF-II gene expression using in situ hybridization histochemistry revealed that IGF-II is expressed by tumor cells in only 5 of 21 neuroblastomas, but is detectable in cells of nonmalignant tissues including adrenal cortical cells, stromal fibroblasts, and eosinophils in all 21 tumors. These findings indicate that IGF-II may function as an autocrine growth factor for some neuroblastomas and as a paracrine growth factor for others. They suggest that the growth regulatory pathways utilized by neuroblastoma mimic those used in the precursor cell type from which individual tumors arise.

Human neuroblastoma cell growth in xenogeneic hosts: comparison of T cell-deficient and NK-deficient hosts, and subcutaneous or intravenous injection routes.

We have examined two features of neuroblastoma cells that had not been well-characterized in a xenogeneic model: The cells display unusual immunologic properties in other experimental systems, and the original tumors display widespread and characteristic patterns of metastasis. To determine the most appropriate immunodeficient host for primary tumor growth, T cell-deficient nude mice, NK-deficient beige mice, beige-nudes, and controls were injected with the well-characterized line CHP-100. To define the pattern of tumor spread, complete autopsies were performed following subcutaneous, intraperitoneal and intravenous injections. CHP-100 consistently formed subcutaneous tumors in T cell-deficient mice (nude and beige-nude), but not in T cell-competent mice (beige, heterozygous nu/+ and bg/+, or wild-type). The growth rate and final size of the subcutaneous tumors were not greater in beige-nudes than in nudes. All mice showed early CHP-100 cell death after subcutaneous injection; the nature of the immunodeficiency was more relevant for the surviving subpopulation. Widespread dissemination was seen following intravenous injection, particularly in beige-nudes. Aspects of the growth patterns were appropriate to the tumor of origin. The behavior in immunodeficient mice suggests that T cells can play a role in controlling the growth of these cells; the next steps will be to define the effector mechanisms, and to determine if they can be exploited for human patients. The hematogenous spread following intravenous injection suggests that insights into the control of blood-borne tumor may also come from further study of this model.

Beckwith-Wiedemann syndrome with unusual hepatic and pancreatic features: a case expanding the phenotype.

We describe an infant with Beckwith-Wiedemann syndrome (BWS) who had hepatic and pancreatic findings not previously described in BWS. These were biliary dysgenesis and enlargement and cystic dysplasia of the pancreas. The biliary dysgenesis was characterized by proliferation of abnormally shaped ducts in the portal tracts. Massive enlargement and cystic dysplasia of the pancreas was associated with ductular proliferation, virtual absence of normal exocrine tissue, and an increase in endocrine tissue.