SUP: October 97 Case of the Month

Pseudomesotheliomatous Pleural Effusion
Sections Clinical History Cytology Electron Microscopy Diagnosis Discussion Reader Feedback	Electron Microscopy Although the specimen was fixed in buffered formalin, there was excellent preservation of cellular details. All the sections showed a monomorphic proliferation of loosely dispersed neoplastic epithelial cells rarely related to each other by interdigitating thin, tortuous, occasionally branching filopodia. Desmosomes or desmosome-like junctions were not seen.
	Figure 3 [Magnify]	Figure 4 [Magnify]

	The periphery of the cell exhibited a prominent layer of thin partly branching microvilli coated by a thin layer of glycocalyx.
	Figure 5 [Magnify]	Figure 5a [Magnify]

	The cell cytoplasm was abundant and contained a well developed golgi apparatus. There were occasional primary and secondary simple lysosomes. Most cells contained occasional, small, osmiophilic, immature lamellar bodies.
	Figure 6 [Magnify]

	Clusters of small electron-lucent mucinous vesicles were also seen. Mitochondria were well preserved. Rare pockets of alpha-glycogen particles were seen in a few cells.
	Figure 7 [Magnify]

	Perinuclear bundles of intermediate (tonofilaments) were not identified. The cell nuclei were round to oval with deep invaginations of the nuclear envelope. The chromatin was evenly distributed. There were segregated macronucleoli with prominent nucleonemata. Mitoses and centrioles were seen.

	Discussion

October 1997 Case-of-the-Month

Pseudomesotheliomatous Pleural Effusion