PART TWO
Diagnostic Cytology
Fig. 19.87 Smear of pleural effusion depicting a keratinizing cell of
metastatic squamous cell carcinoma. The nucleus has undergone almost
complete lysis (Papanicolaou x HP). Reproduced with permission from
Smith-Purslow MJ, Kini SR, Naylor B: Cells of squamous cell carcinoma in
pleural, peritoneal and pericardial fluids. Origin and morphology.
Acta Cytol
1989;33:245-253.
Fig. 19.88 Smear of pleural effusion depicting a tadpole type of
squamous cell carcinoma of metastatic bronchogenic squamous cell
carcinoma (Papanicolaou x HP).
nuclear angulation not seen in lymphocytes. Like lymphocytes,
they have very little cytoplasm or may seem to possess none,
appearing to be composed entirely of hyperchromatic nuclei.
Small-cell carcinoma cells may form large cohesive clusters
that have most unusual shapes (Fig. 19.91). Smaller clusters
frequently exhibit a characteristic type of articulation in which
one cell seems to be capping another, with its nucleus acquir-
ing a quarter-moon shape or, in its extreme form, in which a
tiny, compact group of cells acquires an onion-skin appearance
(Fig. 19.92).
Because the cells of small-cell carcinoma in serous effu-
sions are so small, it is easy to overlook them when only a
few are present. Spriggs and Boddington recommended use of
Romanowsky-stained air-dried smears for diagnosing small-cell
carcinoma because in this type of preparation the cells are larger
and more frequently show a small amount of cytoplasm.184
Cells of a small-cell carcinoma do stand out more in the air-
dried preparations; however, once familiarity with these cells in
Papanicolaou-stained preparations is acquired, they should not
Fig. 19.89 Cell block of peritoneal effusion depicting metastatic
squamous cell carcinoma of the uterine cervix (H&E x LP). Reproduced
with permission from Smith-Purslow MJ, Kini SR, Naylor B: Cells of squamous
cell carcinoma in pleural, peritoneal and pericardial fluids. Origin and
morphology.
Acta Cytol
1989;33:245-253.
Fig. 19.90 Smear of pleural effusion depicting cells of small-cell
carcinoma, some isolated, some appearing as amorphous clusters, and
some in tiny chains reminiscent of a silhouette of the vertebral column. The
nuclei are slightly angulated and show more variation in size and shape than
those of lymphocytes. The tight cohesiveness of these cells would never
occur with lymphoid cells (Papanicolaou x MP).
be overlooked. They may be readily identified in cell-block prep-
arations; in these preparations, the cells frequently show more
cytoplasm, and their nuclei may retain their elongated form, as
seen in tissue sections (Fig. 19.93).
A serous effusion containing cells of a small-cell carcinoma
may be mistaken for one containing lymphoma cells and vice
versa. Lymphoma cells do not form cohesive clusters, either small
or large, as do the cells of small-cell carcinoma. Furthermore,
their slightly angulated outline should prevent the cells of small-
cell carcinoma from being misinterpreted as lymphoma. Many
cells of small-cell carcinomas become necrotic, producing faintly
staining cellular particles as the cells undergo lysis, or they may
form dense, shrunken, hyperchromatic, pyknotic nuclei, thereby
simulating lymphocytes. Other small-cell, nonlymphomatous
malignant neoplasms in serous fluids, such as neuroblastoma,
Ewing sarcoma, or Wilms tumor, may resemble bronchogenic
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