Fig. 13.116 Metastatic colon carcinoma showing the characteristic
palisading of columnar tumor cells with elongated nuclei and necrosis. Fine-
needle aspirate (Papanicolaou x MP).
Fig. 13.117 Metastatic adenocarcinoma from colon showing
vacuolated, mucus-containing tumor cells. Sputum (Papanicolaou x OI).
In some adenocarcinomas metastatic from the colon, pat-
terns suggestive of the colonic origin of the neoplasm may be
manifested in cytologic material. The first pattern is that of
tissue fragments of tumor with columnar differentiation and
elongated nuclei forming a palisade-like arrangement. The
nuclei are very hyperchromatic with macronucleoli.
sive tumor necrosis is a frequent and very characteristic finding
(Fig. 13.116).475 The second pattern is that of clusters of malignant
signet ring-type cells with striking peripheral displacement of the
nucleus by a secretory vacuole (Fig. 13.117). Stains for mucin
are positive. Two examples of metastatic malignant melanoma
with and without pigment are shown in Figs 13.118 and 13.119.
Although the intranuclear cytoplasmic invagination in the cell
in Fig. 13.119 is frequently seen in melanoma, it is not diagnos-
tic, and its presence does not rule out other lesions including
benign ones. Other neoplasms metastatic to the lung reported
in sputum, bronchial material, or bronchioloalveolar lavage
have included choriocarcinoma,476 giant cell tumor of bone,477,478
medullary carcinoma of the thyroid,479 urothelial carcinoma,484
melanoma,480,481 mesothelioma,482,483 immunoblastic lymphad-
enopathy,485 adamantinoma of the tibia,486 and epithelioid sar-
coma (mimicking squamous cell carcinoma) of the arm.487
Fig. 13.118 Metastatic malignant melanoma. The cytoplasm is dense
and cyanophilic and without melanin. Bronchial brushing (Papanicolaou x OI).
Fig. 13.119 Cell from metastatic malignant melanoma showing
intranuclear cytoplasmic invaginations. Fine-needle aspirate
(Papanicolaou x OI).
The opportunity to study the cytology of tumors metastatic
to the lungs has been markedly increased by the use of FNA
to sample the pulmonary nodules of metastatic disease. This
aspect of the development of FNA of the lung has been unusu-
ally innovative in that it has resulted in a major modification of
the diagnostic approach to patients with suspected metastatic
tumor. Before the advent of FNA, such patients would have
been subjected to thoracotomy or treated on the basis of radio-
logic and clinical findings. In these patients, the aspirates usu-
ally reveal the answer to the critical questions of malignancy,
differentiation, and organ of origin. In patients with multiple
primary cancers, additional information about which primary
has metastasized may be provided.
In the diagnostic assessment with FNA of a patient with
suspected cancer metastatic to the lung, the case should be
approached in the same manner as evaluation of tissue from
open biopsy. The patient's clinical history must be reviewed for
either documentation or prior suspicion of a preexisting neo-
plasm. All prior histologic and cytologic specimens should be
reviewed and the cellular changes in the FNA compared with the
preexisting diagnostic material. In the absence of known prior
cancer, immunocytochemical techniques may be of some help.