No abstract

Cell proliferation has been studied in the human cerebellar cortex between the 24th gestational week and the 12th postnatal month. Intensive cell formation has been found in the external granular layer (EGL) of the human cerebellum, where the highest cell proliferation rate occurs between the 28th and 34th gestational weeks. This is followed by a gradual decrease that lasts up to the eighth postnatal month. As late in development as the fifth postnatal month, still 30% of cells of the EGL are labeled with the monoclonal antibody Ki-67, which is specific for dividing cells. The width of the EGL remained unchanged from the 28th gestational week to the end of the first postnatal month, when it starts to decrease and completely disappears by the 11th postnatal month. Large number of Ki-67 labeled cells occurs in the internal granular layer (IGL) between the 24th and 28th gestational weeks. From the 36th week onwards, the labeling index is less than 1%, although a few labeled cells have always been found in this layer even in the late postnatal period. Labeled cells are distributed in the entire width of the IGL. However, from the 34th gestational week, almost all labeled cells are found among and directly below the Purkinje cells. Their position, the nuclear features, and their occasionally stained cell processes suggest that those are Bergmann glial cells. There are few Ki-67 labeled cells in the molecular layer (ML) and in the white matter (WM) of the cerebellum throughout the examined period. It is likely that most of these are glial cells. Pyknotic index has been found to be small in all layers of the cerebellum during the examined period.

The clinicopathologic features of 136 gastrointestinal stromal tumors were analyzed. The tumors occurred in 60 women and 76 men, ranging in age from 19 to 88 years (median 59 years, mean 59.2 years). Sixty-one cases arose from stomach, 38 from small intestine and 11 from colon or rectum. Abdominal cavity was indicated as tumor site in 10 cases, but the extra-gastrointestinal origin using strict criteria was not proved. Four locally recurrent cases and 12 metastatic samples were also included. The primary and recurrent tumors ranged in size from 0.5 to 30 cm (mean 8.3 cm). The large number of high-grade cases (85 of 112 classifiable) is alarming and emphasize the importance of oncology care. Histologically, ninety-two cases were classified as spindle cell while 11 as epithelioid GIST. Mixed cellularity was seen in 33 cases. Skeinoid fibers were present in 14 and coagulation necrosis in 40 primary cases. Ulceration observed by microscopic examination was common (36 of 110 cases, 32.7%), explaining the clinically frequently observed gastrointestinal bleeding. Unusual histological features such as stromal hyalinization and nuclear palisading were present in 30 and 27 cases, respectively. Immunohistochemical CD117 (c-kit) positivity was documented in 133 cases. Three cases with CD117 negative results were included, because their morphology was most consistent with GIST and immunohistochemical reactions excluded the possibility of other neoplasms. CD34 positivity was seen in 70%, alpha-smooth muscle actin positivity in 39.6% of examined cases. Only one case showed desmin reactivity and seven had S100 positive tumor cells. For h-caldesmon 39 cases proved to be positive (60.9% of the tested cases).

Aim-Solid and papillary epithelial neoplasm (SPEN) is an uncommon pancreatic tumour. Very rarely it has also been described outside the pancreas, usually arising from heterotopic pancreatic tissue. This report summarises all the published extrapancreatic SPENs and documents the sixth such case arising from heterotopic pancreatic tissue of the transverse mesocolon in a 15 year old girl. Methods/Results-Histological and immunohistochemical examination revealed typical papillary and solid areas composed of columnar, cuboidal, and round cells, which were focally positive for vimentin, cytokeratin, neurone specific enolase, carcinoembryonic antigen, 1-antitrypsin, 1-antichymotrypsin, and negative for neuroendocrine markers (neurofilament, PGP 9.5, chromogranin A, synaptophysin, and S100), p53, and oestrogen and progesterone receptors. Electron microscopy showed scant zymogen but no neurosecretory granules. In agreement with the flow cytometric result of diploidy, comparative genomic hybridisation (CGH) did not reveal loss or gain of genetic material, and the in situ hybridisation analysis of the RB1 and p53 genes revealed no abnormality in the 13q and 17p arms. Conclusions-Immunohistochemical and electron microscopic data support exocrine diVerentiation. The CGH and the flow cytometric results suggest a subtle, yet unknown genetic change, rather than a large genetic alteration. RB1 and p53 in situ hybridisation ruled out the role of deletion at these sites in the pathogenesis of SPEN. Interestingly, review of the published and the present heterotopic pancreatic SPENs identified the mesocolon as the most common anatomical site (four of six), despite the very rare occurrence of ectopic pancreatic tissue at this site. (J Clin Pathol 2001;54:241-246) Keywords: solid papillary epithelial neoplasm; heterotopic/ectopic pancreas; mesocolon Solid and papillary epithelial neoplasm (SPEN) is a rare tumour in the pancreas. Although more than 300 cases have been reported in the pancreas, the occurrence of SPEN at a heterotopic site is not well recognised. Our literature review identified only five previously published cases.1-5 The histological diagnosis of SPEN is often diYcult, even more so when it occurs at an ectopic site. The histogenesis is still poorly understood and the molecular pathological data are limited. A 15 year old girl was admitted to the department of paediatrics, University Medical School of Pécs, Hungary, with a history of abdominal pain of recent onset and abdominal distention of several years duration. On physical examination, a large tumour filling the left hypochondrium was identified. On the computed tomography (CT) scan a hypodense, intraperitoneal, circumscribed mass dislocating the spleen and left kidney was observed ( fig 1). On laparotomy, a spherical, encapsulated tumour mass was located in the mesocolon. The tumour was not attached to the pancreas and did not appear to invade the colonic wall. It was resected with a segment of transverse colon.The surgical specimen consisted of a circu...

The presence of large cells having simultaneously increased cytoplasmic and nuclear volume accompanied by prominent nucleoli; i.e., differentiating neuroblasts and ganglion cells, is well documented in peripheral neuroblastic tumors (pNTs), and considered as one of the signs of tumor maturation and an indication of a better prognosis of the patients. On the other hand, in 2004 it was reported that large-cell neuroblastoma composed of neuroblastic cells with only nuclear enlargement without recognizable cytoplasmic maturation behaved poorly clinically. Here we are proposing a new pNT subtype in the neuroblastoma category, in addition to the undifferentiated, poorly differentiated and differentiating subtypes: that is large nucleolar neuroblastoma (LNN) characterized by large prominent nucleoli and no or very little amount of discernible cytoplasm. LNN, whose neuroblastic cells are often large in size due to nuclear enlargement, includes those tumors previously categorized into the large-cell neuroblastoma group. LNN tumors, regardless of the size of nuclei, seem to behave aggressively with a very poor prognosis of the patients. It is speculated that nucleolar enlargement without cytoplasmic maturation in LNN tumor cells can be a sign of MYCN amplification.

Intracardiac manifestation of hepatocellular carcinoma (HCC) is a rare condition and an uncommon finding even at autopsy. Pulmonary tumor embolism as a presenting feature of HCC has been published only twice previously. In our case report, a 63-year-old man presented with high fever and six episodes of recurrent pneumonias during the last half year. Echocardiography was performed, a solid mass was found in the right atrium. Transesophageal echocardiography proved a tumor mass in the inferior vena cava (IVC) extending into the right atrium, abdominal ultrasound revealed tumor mass in the IVC and a solid tumor in the liver. Combined liver and heart surgery was attempted in order to remove the tumor mass from both the liver and the right atrium. Acute cor pulmonale occurred during tumor removal from the right atrium and the patient expired. In addition to local factors the possibility of embolization should arise in the background of recurrent pneumonia. Occult carcinoma must be included in possible causes of recurrent pulmonary embolism. Searching for primary malignancy should include HCC as frequent cause of hypercoagulability. In case of HCC, echocardiography is suggested because of the possibility of expansion in IVC or right atrium and tumor-embolization.

No abstract

Heterotopia of pancreatic tissue is a common developmental anomaly. Although ectopic pancreatic tissue is mostly found in the gastrointestinal tract, localization in the mediastinum is extremely rare. We report a 32-year-old male patient who had an urgent thoracotomy two years ago due to a thoracic surgery. During the thoracotomy fragments of a partly necrotic cystic mass in the right thorax were removed and decortication was performed. Two years later the patient was hospitalized again because of haemoptoe and atypical chest pain. A residual cystic mass was detected between the right hilum and the ascending aorta connecting to the pericardium, the superior vena cava and the aorta on the chest CT. After the operation a mediastinal cyst was diagnosed, with a pancreatic tissue by histology.