Pleural, Peritoneal, and Pericardial Effusions
Fig. 19.13 This cell block of pleural effusion consists of spontaneously
formed clot on the left and induced clot on the right, both prepared from
the same specimen. The latter, composed of a delicate, newly created fibrin
network, contains many more fragments of adenocarcinoma than the
former, which is composed of dense, contracted fibrin. This fluid clotted
spontaneously, but before it did, most of the fragments of adenocarcinoma
had settled to the bottom of the container. Therefore, the spontaneously
formed clot, which formed later, contained only a small number of fragments
of carcinoma, whereas the specimen obtained by centrifugation, from which
the induced clot was prepared, contained numerous fragments (H&E x LP).
Fig. 19.14 Cell block of peritoneal effusion containing a fragment of liver
obtained when the paracentesis needle traversed the liver en route to the
peritoneal cavity (H&E x LP). The inset shows a hepatocyte in a smear of the
fluid (Papanicolaou x HP).
fibrin (Fig. 19.16), skin (Fig. 19.17), squamous epithelial cells
(Fig. 19.18), skeletal muscle (Fig. 19.19), cartilage (Fig. 19.20),
colonies of microorganisms (Fig. 19.21), accessory skin struc-
tures in subcutaneous adipose tissue (Fig. 19.22), fragments of
hyperplastic mesothelium with collagenous stroma (Fig. 19.23),
fibroblastic tissue, vegetable cells, and pulmonary parenchyma.
Many of these entities were either not present or were not recog-
nized in the smear preparations.
Key features of cell blocks
• Spontaneous clot may enmesh virtually all the cells;
• Cell blocks will increase percentage of positive results;
Fig. 19.15 Cell block of pleural effusion containing a fragment of
granulation tissue (fibroblasts, angioblasts, and inflammatory cells) from
the surface of inflamed pleura (H&E x MP).
Fig. 19.16 Cell block of pleural effusion containing cholesterol clefts, a mani-
festation of long-standing effusion, in this case due to rheumatoid pleuritis
(H&E x LP). Reproduced with permission from Naylor B: The pathognomonic
cytologic picture of rheumatoid pleuritis.
• Cell blocks may reveal histologic aspects of neoplasm;
• Cell blocks may reveal entities not visible in smears.
The Serous Cavities
The embryonic coelomic cavity gives rise to the serous cavities:
pleural, peritoneal, and pericardial. The term
refers to the
small amount of serum-like fluid each cavity contains. The term
is also applied to the cavity partly surrounding each testis formed
by the tunica vaginalis testis, an embryonic extension of the peri-
toneal cavity. Because our experience with hydrocele fluid is vir-
tually nonexistent, this type of specimen is not dealt with. For
a comprehensive account of the cytology of hydroceles, readers
should consult the monograph by Spriggs and Boddington.9
The serous cavities are commonly (and imprecisely) referred
Under normal conditions, the cavities are col-
lapsed sacs invaginated by the heart, lungs, and intestines. Each
cavity is completely closed (except the peritoneal cavity at the
points where it receives the fimbriated ends of the fallopian