AIMS:The differentiation of adrenocortical carcinomas from adenomas may be difficult based on morphology alone. Differential expression of insulin-like growth factor (IGF) II and cyclin-dependent kinase (CDK) 4 has recently been described in these tumours. The aim of this study was to investigate the diagnostic usefulness of these markers immunohistochemically.METHODS AND RESULTS:We examined 22 benign and 17 malignant adrenocortical tumours and compared IGFII and CDK4 expression with known immunohistochemical as well as morphological criteria of malignancy. Thirteen of 17 carcinomas showed immunohistochemical reactivity for IGFII, whereas all adenomas but one were negative. Intense CDK4 expression was detected in 11 of 17 carcinomas but was present in only three of 22 adenomas. The MIB1 index was >5% in 14 of 16 carcinomas and was <5% in all adenomas but one. The combination of IGFII immunohistochemistry with MIB1 index led to high sensitivity and specificity in detecting adrenocortical carcinomas.CONCLUSIONS:IGFII and MIB1 are helpful immunohistochemical markers to predict malignancy in adrenocortical neoplasms. These markers can be used in addition to clinical, gross and morphological features to establish a diagnosis in difficult cases.

The morphological characteristics and percentage of the cellular associations between gonadotrophs (LH- and FSH-secreting cells) and other cellular types were studied in pituitary pars distalis of adult male viscachas (Lagostomus maximus maximus) by double immunohistochemistry using specific antibodies to LH, FSH, PRL, GH, ACTH, TSH and S-100 protein (by folliculostellate cells; FSC), during long and short photoperiods. Bihormonal gonadotrophs were observed in ventro-medial and dorsal regions, interspersed between monohormonal gonadotrophs, and their number increased in short photoperiod. LH- and FSH-gonadotrophs were found around lactotrophs, enclosed by somatotrophs in the dorsal region, and associated with irregular corticotrophs. Gonadotrophs and thyrotrophs were associated along blood vessels and follicular structures. The cytoplasmic prolongations of FSC were in contact with both gonadotrophs. The percentage of LH–FSH, LH–ACTH, LH–FSC, FSH–LH, FSH–PRL, FSH–GH, FSH–ACTH, FSH–TSH and FSH–FSC associations decreased, whereas LH–PRL increased in short as compared to long photoperiod. The most abundant associations were LH–GH and LH–TSH during long photoperiod, but LH–GH and LH–PRL during short photoperiod. FSH–GH and FSH–PRL were the most numerous associations, and LH–FSC and FSH–FSC were the less abundant ones in both photoperiods. These results provide the morphological evidence for specific cellular associations between gonadotrophs and other cellular types of viscacha pituitary.

Plasma prolactin (PRL) is released from lactotrophs in the anterior pituitary. As plasma PRL levels rise during incubation in domestic fowl, the number of lactotrophs (PRL-immunoreactive, PRL-IR cells) increases while the number of growth hormone secreting cells, somatotrophs (GH-IR cells), declines. We measured plasma PRL levels using radioimmunoassay (RIA) and examined the distribution of lactotrophs and somatotrophs in the anterior pituitary of breeding and nonbreeding zebra finches of known ages with and without prior breeding experience using fluorescent immunohistochemistry (IHC). Plasma PRL levels were higher in breeding than in nonbreeding birds, regardless of age, sex, or previous breeding history. PRL-IR cells were localized primarily, but not exclusively, to the cephalic aspect of the anterior pituitary (AP) and along the ventral margin. Birds with prior reproductive experience had more PRL-IR cells than birds with no prior reproductive experience and breeders had slightly higher PRL-IR cell counts than did nonbreeders, but there was no correlation between the number of PRL-IR cells and plasma PRL levels. GH-IR cells were concentrated in the caudal aspect of the AP with some cells in the cephalic lobe, but numbers did not differ between any of the groups studied. An increase in PRL-IR cells corresponded with an increase in GH-IR cells. An increase in lactotroph number with reproductive experience in zebra finches may facilitate future reproductive events by allowing for more robust PRL secretion and increased reproductive success.

The membrane glycoprotein CD44 may be associated with aggressive behavior, dissemination, and poor prognosis of a variety of human tumors. In order to extend our knowledge on the expression and significance of CD44 in cells of the dispersed neuroendocrine system we investigated a spectrum of 134 neuroendocrine tumors, including pituitary adenomas, medullary thyroid carcinomas, parathyroid adenomas, pheochromocytomas, neuroblastomas, small-cell lung carcinomas, and bronchopulmonary, pancreatic, and gastrointestinal neuroendocrine tumors immunohistochemically for CD44 standard and variant exon-encoded gene products (CD44v3, -v4, -v5, -v6, -v9). Furthermore, we compared protein expression with that of CD44 mRNA by reverse-transcriptase PCR and Southern blot hybridization in a subset of tumors. Our results show that CD44 expression is correlated with the "histogenetic origin" of the appropriate neuroendocrine neoplasm. Endoderm-derived tumors generally express 3'-end CD44 variant exon-containing isoforms, whereas neural crest-derived tumors rarely are positive for CD44. Furthermore, we provide evidence that CD44 expression is not correlated with metastatic disease or a particular hormonal phenotype but exhibits an association with the degree of cellular differentiation. Thus, CD44 is not useful as marker for malignancy or prognosis. The number of patients with clinical follow-up data in our study was too small to allow definite conclusions about a possible correlation between CD44 expression and prognosis. But CD44 may help to better classify neoplasms with an unclear neuroendocrine phenotype.

Isoforms of the transmembrane glycoprotein CD44, which are generated by alternative splicing of nine variant exons, have been implicated in tumor cell adhesion, invasion and metastatic spread and may be indicators of the degree of tumor differentiation. Since little is known about the distribution of CD44 in non-neoplastic neuroendocrine cell types, we systematically investigated 42 samples of tissue from different organs, including the pituitary gland, thyroid, parathyroid, adrenal gland, lung, pancreas, stomach, duodenum, jejunum, ileum, appendix, and colon, immunohistochemically for the expression of CD44 standard and variant exon-encoded gene products (CD44v3, v4, v5, v6, v9). Furthermore, double immunolabeling for CD44 and a variety of peptide hormones was applied to characterize the different neuroendocrine cell types. Our results show that neuroendocrine cells derived from the neuroectoderm lack CD44 immunoreactivity. However, those originated from the endoderm exhibit a variable CD44 immunostaining which is related to their anatomical localization and the degree of differentiation irrespective of the hormone produced. Furthermore, we demonstrate that CD44 positive neuroendocrine cells predominantly express CD44 isoforms of the epithelial type and that hyperplastic clusters of neuroendocrine cells of pancreatic ducts express CD44 most probably as a sign of dedifferentiation.

For 2 years a 72-year-old man had suffered from nonspecific upper abdominal discomfort and hepatomegaly. The gamma-glutamate transaminase concentration was increased to 121 U/l, the erythrocyte sedimentation rate was 80 mm in the first hour. Histological examination of tissue from the enlarged liver (22 cm in the midclavicular line) revealed the diagnosis of amyloidosis. The gastric mucosa, duodenum and rectum were not involved. Two years later ascites developed; six months after this he was again hospitalized in hepatic coma. Now, for the first time, a type IgA-lambda paraprotein was demonstrated by serum immunoelectrophoresis. The patient died of slowly progressing anicteric liver failure after having been ill for a total of 4 1/2 years. At autopsy there were extensive amyloid deposits throughout the liver and spleen so that the structure of these organs was hardly recognizable. The amyloid deposits in the liver were restricted to the glomerular region, while there was no amyloid in the heart. Histochemical tests showed that the deposits were strongly positive to the anti-lambda antibody. This was thus a case of primary (AL-lambda) amyloidosis of the liver and spleen which had taken an unusually prolonged course, because the heart was not involved at all and the kidneys only slightly.

A female patient suffering from a bronchial neuroendocrine tumor with unilateral left-sided carcinoid heart disease is reported. Repeated x-ray films of the chest showed a slowly growing lung tumor in the left lower lobe. The patient refused any diagnostic or therapeutic procedure to define the type of the tumor. During the follow-up of 24 years she developed severe mitral and moderate to severe aortic insufficiency, both invasively quantified by thermodilution techniques. During surgery for double valve replacement the patient died from left ventricular heart failure. Necropsy revealed the typical pattern of a bronchial neuroendocrine tumor without metastases. Examination of the heart disclosed the characteristic deposits of fibrous tissue on the cusps of both the mitral and the aortic valves whereas the right heart showed no abnormalities. Review of the literature suggests the unilateral left-sided carcinoid heart disease to be a very rare finding, its pathogenesis remains to be elucidated.

Parvovirus infection of pregnant women leading to a transplacentar infection of the fetus may result in hydrops fetalis, and ultimately in intrauterine death of the fetus. In situ hybridization with a biotinylated as well as with a 35S-labeled probe for human parvovirus B19 was performed on formalin-fixed paraffin-embedded (FFPE) tissue from a fetus suffering from non-immunologic hydrops fetalis. Histology was suggestive of viral infection probably with human parvovirus. Parvovirus DNA could be detected and precisely localized mainly in the nuclei of erythroid precursors cells within fetal blood vessels of all organs examined. There was no detection of B19 nucleic acid in parenchymal cells of the placenta or the fetal organs, nor within maternal blood cells. These findings are in agreement with the well-known properties of animal parvoviruses to replicate exclusively in proliferating cells. Taking into consideration the problems in diagnosing human parvovirus infection by light microscopy, we conclude that in situ hybridization with an appropriate non-radioactive probe is a valuable, rapid and safe complementary detection method for the diagnosis and study of human parvovirus infections. The 35S-labeled probe is more sensitive than the biotinylated probe, but has the disadvantages of lower resolution of the signal, longer duration of the assay, the hazard of radioactivity and the shorter shelf-life of the probe.