Diffuse Pleural Rhabdomyosarcoma with Persistent Pleural Effusion

A unique case of embryonal rhabdomyosarcoma arising at the left pleura of a 7-year-old Japanese girl is reported. The present case was characterized by persistent pleural effusion, and the malignant cells incidentally found in it were the first diagnostic clue. The tumor showed a rare growth pattern involving diffuse thickening of the parietal pleura. Biopsy of the thickened parietal pleura upon thoracotomy revealed embryonal rhabdomyosarcoma largely composed of immature mesenchymal cells. Immunohistochemical demonstration of creatinine phos-phokinase MM was most helpful among several types of immunostain for the histopathological diagnosis. Ultra-structurally, thin filaments with primitive Z bands could be seen in some tumor cells. Intensive clinical examination revealed only diffuse thickening of the parietal pleura, which was reduced by chemotherapy. This is the first documented case of rhabdomyosarcoma arising at the pleura. Previous reports of rhabdomyosarcoma arising at unusual sites are reviewed and the histogenesis of this tumor is briefly discussed. Acta Pathol Jpn 39: 803 809, 1989.     

Pleural amyloidosis

Pleural amyloidosis has been reported rarely, and the diagnosis of this disease by Cope needle biopsy has, to our knowledge, been reported only once previously. We report two patients in whom the diagnosis of pleural amyloidosis was made by biopsy specimens obtained in the examination of large, unilateral pleural effusions. In one patient, the diagnosis was made by Cope needle biopsy. The clinical and diagnostic significance of these cases are discussed.     

Pleural Epithelioid Hemangioendothelioma

Epithelioid hemangioendothelioma (EHE) is a rare tumor of vascular origin. While it can be found in any tissue, it is most often found in lung and liver and usually has an intermediate behavior. EHEs originating from pleural tissue have been less frequently described than those from other sites. Furthermore, to date, all of the cited pleural EHEs were described as highly aggressive. In the present report, we describe a rare case of pleural EHE extending to lung and bone in a 31-year-old woman. The histological diagnosis was confirmed by both conventional examination and immunohistochemistry. Her disease stabilized during the 4th course of adriamycin (45 mg/m², day 1-3), dacarbazine (300 mg/m², day 1-3) and ifosfamide (2,500 mg/m², day 1-3) with mesna, and she survived for 10 months after the diagnosis.     

A Primary Pleural Tumor

Contamination of a biopsy or surgical specimen with spurious tissue is an uncommon but potentially disastrous event. In this regard, the case of a 5-year-old boy referred for treatment of an abdominal tumor is presented. Sections made from paraffin blocks brought by the family showed both neuroblastoma and a spindle cell sarcoma, initially suggesting the possibility of divergent or mixed differentiation. However, the resemblance of the spindle cell component to well-differentiated leiomyosarcoma rather than rhabdomyosarcoma raised the suspicion that a specimen contamination had occurred. Electron microscopy was instrumental in confirming the smooth muscle nature of the sarcomatous component, leading to a fluorescence in situ hybridization study, which established that this component was incompatible with the patient's gender. This case illustrates that even when the light microscopic differential has been compromised by specimen mishandling, electron microscopy can at times provide useful information regarding specimen identity, as well as assist in sorting out the correct diagnosis.     

Pleural function and lymphatics

The pleural space plays an important role in respiratory function as the negative intrapleural pressure regimen ensures lung expansion and in the mean time maintains the tight mechanical coupling between the lung and the chest wall. The efficiency of the lung–chest wall coupling depends upon pleural liquid volume, which in turn reflects the balance between the filtration of fluid into and its egress out of the cavity. While filtration occurs through a single mechanism passively driving fluid from the interstitium of the parietal pleura into the cavity, several mechanisms may co‐operate to remove pleural fluid. Among these, the pleural lymphatic system emerges as the most important one in quantitative terms and the only one able to cope with variable pleural fluid volume and drainage requirements. In this review, we present a detailed account of the actual knowledge on: (a) the complex morphology of the pleural lymphatic system, (b) the mechanism supporting pleural lymph formation and propulsion, (c) the dependence of pleural lymphatic function upon local tissue mechanics and (d) the effect of lymphatic inefficiency in the development of clinically severe pleural and, more in general, respiratory pathologies.