Benign multicystic mesothelial proliferation of the peritoneum: immunohistochemical and electron microscopical study of a case and review of the literature.

We report a case of benign multicystic mesothelial proliferation (the so-called multicystic peritoneal mesothelioma) arising multifocally in the abdomen of a 46-year-old white man. His anamnesis showed an 8-year history of intermittent pain in the right lower abdominal quadrant. Mucin stains, immunohistochemistry, and electron microscopy confirmed the mesothelial origin of the lesion. Review of the available literature allowed us to find another 85 reported cases of benign multicystic mesothelial proliferations of the peritoneum. Out of these cases, eighteen only occurred in men, the majority being reported in middle-aged women mostly with complaints of abdominal pain. Electron microscopy or immunohistochemistry are needed to make a differential diagnosis towards other multicystic lesions, such as peritoneal cystic lymphangioma. Although multicystic mesothelial proliferations of the peritoneum have often been regarded as benign neoplasms, the true nature--neoplastic or hyperplastic--of these lesions still remains greatly elusive. Therefore, we believe that the unbinding term benign multicystic mesothelial proliferation (first used with regard to the unique hitherto reported case arisen in the pleural cavity) should be considered at present more appropriate to indicate even these peritoneal lesions.

Secondary amyloidosis and cystic fibrosis. A morphological and histochemical study of five cases.

The pathological findings of five cases of amyloidosis associated with Cystic Fibrosis are reported. Rectal biopsy led to the diagnosis of amyloidosis in four patients. In three cases the diagnosis was confirmed at autopsy, with involvement of spleen, liver, kidneys, adrenal glands, thyroid and other organs. It seems that Secondary Amyloidosis provokes a significant, although rare, complication of Cystic Fibrosis as greater numbers of these patients survive into adulthood.

Atypical lung carcinoid with GFAP immunoreactive cells.

A case of atypical carcinoid with peculiar histological and ultrastructural pattern and immunohistochemical phenotype is presented. The neoplasm is composed of three types of cells. Type 1 cells are small to medium sized, fusiform, with scarce cytoplasm and are arranged in fascicles. Type 2 cells are cuboidal and line acinar structures. Type 3 cells have more abundant eosinophilic cytoplasm, larger nuclei and are arranged in fascicles intersecting with fascicles of type 1 cells, and sometimes surround acinar structures. The three cell types are present both in the primary lesion and in its lymph node metastases. Immunohistochemistry demonstrates immunoreactivity of all cell types for general neuroendocrine markers. Cytokeratin immunoreactivity is more prominent in type 1 and 2 cells, and is only focally expressed in type 3 cells. Type 3 cells are also immunoreactive for glial fibrillary acidic protein (GFAP), alpha-actin, S-100 protein, vimentin. Electron microscopic examination confirms the neuroendocrine nature of the cells, and show that type 3 cells have prominent bundles of intermediate filaments, electron-dense granules and junctional complexes. To our knowledge, this is the first case of atypical lung carcinoid with GFAP immunoreactivity. The nature of type 3 GFAP positive cells is unclear. There are some clues pointing to their sustentacular nature, and other ones pointing to a myoepithelial origin, but the data are inconclusive. Type 3 cells may be the malignant counterpart of sustentacular cells seen in typical carcinoids, but their GFAP positivity and the presence of electron-dense granules are very unique features, which differentiates them from sustentacular cells. Alternatively, their unusual GFAP + immunohistochemical phenotype may be due to aberrant expression of cytoskeletal proteins.

Ependymoma of the mediastinum.

A case of primary ependymoma of the mediastinum is reported. The tumor was adherent to the lung and metastasized to adjacent mediastinal lymph nodes. An autopsy showed no evidence of tumor in the central nervous system. The diagnosis of ependymoma was confirmed by the immunohistochemical positivity for glialfibrillary acidic protein. To the best of our knowledge, this is the first reported example of an ependymoma in this location.

Development of innumerable neuroendocrine tumorlets in pulmonary lobe scarred by intralobar sequestration. Immunohistochemical and ultrastructural study of an unusual case.

We describe the microscopic, histochemical, immunohistochemical, and ultrastructural features of hundreds of neuroendocrine tumorlets occurring within a pulmonary lobe severely scarred by intralobar sequestration in a nonsmoking 49-year-old white man. To our knowledge, there have thus far been no descriptions or detailed analyses of neuroendocrine tumorlets arising within a pulmonary sequestration. The neuroendocrine tumorlets appeared in the form of minute aggregates--mostly microscopic, up to a maximum of 0.3 cm in greatest diameter--of small round and short spindle-shaped cells. They were organized in compact nests of fascicles and were supplied with round or elongated euchromatic nuclei and scant weakly eosinophilic cytoplasm. The neuroendocrine tumorlets were clustered around diseased bronchioles or embedded in a fibrotic pulmonary parenchyma with a distinctive infiltrative appearance. Sometimes they lay near an artery channel without an identifiable bronchiole or herniated into distal airways. Most of the neuroendocrine tumorlets were strongly argyrophilic on Grimelius staining. Immunohistochemically, there was reactivity for markers of epithelial and neuroendocrine differentiation together with evidence of orthotopic production of calcitonin, serotonin, and gastrin-releasing peptide and ectopic production of vasoactive intestinal peptide. Ultrastructurally, most of the neuroendocrine cells showed 100- to 120-nm dense-core membrane-bound secretory granules; mucus secretory cells were also present. We prefer the term neuroendocrine tumorlets over the generally used term carcinoid tumorlets, because the nature of these lesions is undefined and the relationship with neuroendocrine pulmonary neoplasms is not yet established.

The role of radiotherapy in the management of choroid plexus neoplasms.

Choroid plexus papillomas are very rarely reported neoplasms in both the surgical and radiological literature. The authors present their series of 7 papillomas and 1 carcinoma. They review the recent and former literature with the aim of demonstrating the role and usefulness of radiotherapy.

[Renal leiomyoma (presentation of a clinical case)]. / Il leiomioma renale (presentazione di un caso clinico).

The authors report a case of symptomatic renal leiomyoma. Such neoplasm is very rare and, as to the symptomatic form, only some tens of cases are recorded.

Interstitial lung granulomas as a possible consequence of exposure to zirconium dust.

A case of interstitial lung granulomas is described in a worker exposed to zirconium compounds. Chest X-rays revealed diffuse slight reticular interstitial radio-opacities (ILO classification, 1/0 s/t). Histological examination of transbronchial biopsy tissue revealed small interstitial nonconfluent granulomas with epithelioid and giant cells showing no central necrosis, with PAS-positive diastase-resistant small weakly birefringent particles in interstitial histiocytes. These histological and stain findings, which are characteristic of zirconium skin lesions and granulomas, suggest zirconium interstitial lung disease.

[Clinical, epidemiological, morphological and etiopathogenetic aspects of benign tumors of hepatocytic derivation, with description of a case of focal nodular hyperplasia]. / Aspetti clinici, epidemiologici, morfologici ed etiopatogenetici dei tumori benigni, di dervazione epatocitaria, con descrizione di un caso di iperplasia focale nodulare.

PIP: Since the introduction of hormonal contraception many studies have been published on the role of oral contraceptives (OCs) in causing liver neoplasms. The tumor registers established in the US, England, and France allow researchers to study the incidence of such tumors, and to better evaluate the population at risk. The most frequent types of benign hepatic tumors are adenomas, hepatocellular adenoma or biliary duct adenoma, and focal nodular hyperplasia. Although morphologically very different, such tumors have been called with a varied and confusing terminology. Liver tumors are usually discovered by chance during laparotomy, and are more numerous in women aged 20-40. Radiography, scintigram and echography and very helpful in diagnosis, but arteriography is still the best diagnostic tool. Therapy consists of simple resection or of lobectomy, when possible. Many authors, however, insist on their sponteneous regression after OC termination, if OCs are the cause. According to the most recent studies OC-caused liver tumors happen more often in patients who have taken mestranol for over 4 years; liver tumors are also more common in multiparous women and may grow very quickly during pregnancy. In recent years the association between liver tumors, benign or malignant, and treatment with androgens has often been documented. This document presents the case of a 26 year old patient hospitalized for pain and for the presence of a large abdominal mass. The patient suffered severe dysmenorrhea and serious menstruation disorders. The patient had never taken OCs but had been treated for a long time with aspirin for headache and with diazepam for a nervous breakdown during adolescence, and more recently during pregnancy. The patient underwent surgery, and a large focal nodular hyperplastic tumor was excised.^ieng

Salazopyrin-induced eosinophilic pneumonia.

A patient with ulcerative colitis developed eosinophilic pneumonia following treatment with Salazopyrin. The pneumonia resolved following discontinuation of the drug and the start of treatment with prednisolone. When the treatment with prednisolone was stopped the patient developed eosinophilic pneumonia again. When the treatment with prednisolone was resumed all side effects disappeared definitively.

Metachronous coexistence of laryngeal pseudolymphoma and squamous cell carcinoma. An unreported case.

An unreported case of metachronous coexistence of laryngeal pseudolymphoma and squamous cell carcinoma is described. The long follow-up of the patient (above 11 years), without any evidence of lymphoreticular disease elsewhere, was in favor of a diagnosis of lymphoid hyperplasia of the larynx. The occurrence in the same organ of a squamous cell carcinoma has allowed the thorough investigation of the reactive lesion. The additional cases of laryngeal pseudolymphoma reported in the English literature are reviewed.

Ultrastructural morphology of folliculo-stellate cells in human pituitary adenomas.

Fifty-six pituitary adenomas were studied by electron microscopy in a search for the presence of folliculo-stellate cells (FSCs) with the aim of evaluating their prevalence and ultrastructural morphology. FSCs were scattered in two adenomas (one oncocytoma and one densely granulated GH cell adenoma) and were numerous in a sparsely granulated GH cell adenoma; their overall prevalence was 5.4%. Ultrastructural examination of the three neoplasms revealed that FSCs were hypertrophic element with abundant cytoplasm and organelles (in contrast to FSCs of the normal pituitary) and no obvious signs of neoplastic transformation. Junctional complexes between FSCs were similar to those described in the normal gland. Numerous follicular structures were lined by FSCs. FSCs in pituitary adenomas are probably nonneoplastic, reactive cells showing signs of hyperactivity, similar to FSCs found during pituitary hypersecretion and in estrogen-induced tumor.

Thymic cyst appearing after treatment of mediastinal non-Hodgkin lymphoma.

We report the first case of a thymic cyst appearing in the course of treatment for non-Hodgkin lymphoma of the anterior mediastinum. The patient was a 9-year-old child in whom an abnormal contour of the left cardiac border persisted after chemotherapy, suggesting residual disease. The mass was found at thoracotomy to be a benign thymic cyst. The lesion was not present 2 years previously, and most likely represented cystic degeneration of the thymus, secondary to lymphomatous involvement. CT scan was not helpful in distinguishing the cystic lesion from residual lymphoma.